Computer Simulation Model of Dynamic BioPhysicochemical Processes in Soils Technical Bulletin 196 Agricultural Experiment Station The University of Arizona Tucson Computer Simulation Model of Dynamic Bio- Physicochemical Processes in Soils by Gordon R. Dutt Marvin J. Shaffer William J. Moore Department of Soils, Water and Engineering Agricultural Experiment Station University of Arizona, Tucson Technical Bulletin 196 October 1972 - 3M Acknowledgments The authors wish to express appreciation to those who made this Bulletin possible. Outside financial support was provided by the U. S. Department of the Interior, Bureau of Reclamation under contract #14 -06 -D -6464 and #14 -06 -D-7057, and to a small extent the IBP Desert Biome #5566 -11. A special word of thanks is expressed to Mr. John Maletic of the Bureau of Reclamation, whose encouragement and practical knowledge of the subject was invaluable. Also the authors wish to thank Dr. Arthur W. Warrick, of the University of Arizona, for his direct help in developing the Moisture Flow Program, and Dr. Thomas C. Tucker of the same University who helped in discussions involving nitrogen transformations and uptake. Abstract A digital computer model was developed to simulate the effect of certain environmental and managerial factors on soil-water -plant systems. From an initial state and time sequential input variables, the model simulates the nonsteady state chemical, physical, and biological changes occurring in the unsaturated soil matrix and percolating water. Processes considered are (1) infiltration and redistribution of soil water; (2) evapotranspiration; (3 ) nitrogen transformations including hydrolysis of urea -N, immobilization of NH4 + -N, mineralization of organic -N, and immobilization of NO3 --N; (4) changes in the solute concentration of soil water due to ion exchange, solubility of gypsum and lime (CaCO3), and dissociation of certain ion pairs; and (5) nitrogen uptake by crops. The model predicts with time the distribution and concentration of the constituents considered: i.e., Ca", Mg", Na +, NH4 +, SO4 -, HCO3 -, Cl -, CO3 -, NO3 -, CaSO4.2H2O. CaCO3, CO(NH2)2, and organic -N. The programs and subroutines simulating the above mentioned processes were verified by comparing predicted values against experimental results found in the literature or determined by experiments carried out for verification. To demonstrate the usefulness of the model, a hypothetical problem of environmental concern was simulated. Predictions for a period of thirteen years were made to assess the effect of three levels of N fertilization on the N content of water reaching the water table. All other factors were held constant. In the problem considered, only the highest level of fertilization substantially increased the N content of the effluent from the soil. Key Words: Soils, Pollution, Water Quality, Nitrogen, Microbiology, Water Movement, Systems Analysis, Fertility, Computer Model. Table of Contents ABSTRACT 1 INTRODUCTION 3 THE SYSTEM 3 THE MODEL 4 Mosture Flow Program Program MOISTRE Subroutine CONUSE Subroutine THEDATE and Integer Function DAY Verification of Moisture Flow Program 5 Biological -Chemical Program 9 Subroutine XCHANGE Subroutine EQEXCH Subroutine TRNSFM Subroutine FL Subroutine UPTAKE Miscellaneous Subroutines Validation of Biological- Chemical Program APPLICATION TO AN ENVIRONMENTAL PROBLEM Input Assumptions Results and Discussion USER'S MANUAL FOR MODEL 6 7 8 8 11 14 15 23 24 24 24 27 27 27 31 Moisture Flow Program 31 Inputs Outputs Restart Capability. 31 32 32 Interface Program 36 Biological- Chemical Program 37 Card Inputs Tape Inputs Card Outputs Tape Outputs Hints on Program Use APPENDIX A. Program Listings B. Sample Card Inputs C. Sample Printed Outputs REFERENCES CITED 38 46 48 49 50 51 51 87 93 100 Introduction With the current utilization of our water resources, degradation of water supplies has occurred in many areas. Increased public awareness of water quality problems has led to the adoption of legislation designed to stop further deterioration of surface water and has required that the impact on the environment be determined for water projects being planned for the future. In the past, judgment based on experience and measured parameters has been used by competent scientists and engineers to estimate the effects of water projects on ecology. However, too often these judgments have turned out to be in error, and persons are demanding that judgments in the future be made on a more quantitative basis. Among the more complex problems is the prediction of the effects of irrigated agriculture on water quality. Methods are needed to predict: (1) the short and long term salt concentration, including salts of nitrogen, in drainage effluent from agricultural areas, (2) the chemical composition of water moving down into ground water aquifers from irrigation projects, and (3) the impact on water quality in an area under study for irrigation. A promising approach to the above problems is the development of a conceptual digital computer model of the dynamic soil -water system. Such a model could be used for predictions, such as above, and as the basis of a true system analysis model for predicting management practices which minimize pollution under economic constraints. Over the past decade the senior author and colleagues have addressed themselves to the development of such a model (20, 21, 23, 24, 25). Like most research, each step provides the basis for the subsequent work. The foundation of the model to be reported on was the development of computerized numerical solutions, predicting from initial non equilbrium conditions, the equilibrium solute composition for soil -water systems at different moisture contents. These numerical solutions involved more than one chemical reaction (ion exchange of Ca ++ and Mg", and solubility of a salt, CaSO4.2H2O, (21) ), and were based on thermodynamics, ion exchange equations, and Debye-Hückel theory. This early work was verified at moisture contents much higher than those encountered under irrigated agriculture, but was later shown applicable to soil systems in the field moisture range (22) Using the above procedures and a finite difference method, a model was developed to predict the changes in solute composition in an effluent from a saturated soil during one -dimensional flow (24). Since the chemical reactions considered were limited, the above model was not applicable to real field situations but the model did demonstrate that such models were feasible. An additional cation, Na +, and an ion pair, CaSO4 were later added to the model (23, 20) The usefulness of activity coefficients and ion pairs in such calculations has been further substantiated (3, 51), and the prediction of the solubility of gypsum in the absence of soil exchangers also has been further evaluated (55). These early models considered only saturated flow and chemical reactions which were rapid compared to the rate of water movement. Also, CaCO3 was not considered and the analytical data required was too great for most practical applications under arid and semi -arid field conditions. The above inadequacies needed to be alleviated. It was felt that a model of the unsaturated soil zone was desirable and that such a model should, in addition to the above, consider the chemistry of nitrogen and additions of water from rainfall and irrigation, fertilizer, and organic residue. It should also consider evapotransporation and the withdrawal of nitrogen by plants. The following work reports on such a predictive model. . . The System In developing a conceptual model of the dynamic soilwater -plant system, the "system" must be defined. Consider a soil in which plants are growing with an underlying water table (Figure 1) Further, consider a vertical flow line from the soil surface to the underlying water table. The basic spacial unit of the "system" is chosen to be one of these flow lines. The reason for this choice of the "system" is that . most equations and methods that are available to consider moisture content and movement, and chemical changes occurring in the soil are less complex for one -dimensional considerations. It should be pointed out, however, that a 3- dimensional flow net may be approximated by joining 1- dimensional sections together. Page 3 MOISTURE FLOW PROGRAM BIOLOGICAL - CHEMICAL -Q -2TABLE NC -Q-I- WATER _ / PROGRAM NT Q' Q ROOT ZONE HORIZONS NODAL NUMBERS CHEMISTRY SOIL SEGMENTS HORIZONS TEMPERATURE HORIZONS ROOT ZONE HORIZONS Figure 1. Spacial division of soil-plant water system along a flow line. The Model Along a flow line the chemical, biological and physical properties of a soil rarely, if ever, are homogeneous. To approximate these field variations and yet to take advantage of mathematical relationships developed for homogeneous soil systems, the soil segment concept is employed ( Figure 1) ; i.e., a finite number of equal length units of soil along the flow lines are considered to be soil segments. Each soil segment is considered to be homogeneous and the same segment may or may not be considered to be homogeneous with its connecting segments. The authors recognize that the solute composition of the soil solution effects moisture movement, however, in this first approximation model it is assumed that these solute -soil interaction effects on moisture movement are negligible in comparison with uncertainty that physical and biological properties effecting water movement can be measured or known. With the above assumption, it is possible to consider moisture movement as independent of chemical changes in the soil solution, hence the problem can be divided into two parts; first those dealing with moisture movement under a growing crop, Moisture Flow Program (which is independent of the second), and those dealing with changes in chemical composition and distribution, Biological -Chemical Program (which is dependent on the first). To facilitate the lengthy calculations involved, computer programs written in Fortran IV (16) were prepared for both of the above parts. A generalized model diagram is shown in Figure 2. In execution of the model, the initial moisture contents and physical properties of the soil (e.g. unsaturated conductivity and diffusivity relationships) are inputs to the Moisture Flow Program as well as the amount and time of water applications (rain or irrigation) and consumptive use data. From the above input the Moisture Flow Program calculates the moisture content and movement at stipulated time intervals for each soil segment. Output from the Moisture Flow Program serves as input to the Biological -Chemical Program, along with the temperature at various stipulated times and depths and initial chemical parameters for the solutes being considered in each soil segment. Also, the amount and time of application of fertilizer and organic matter residues and the concentrations of solutes in the applied water are inputs to the above program. The Biological-Chemical Program discussed in general later calculates the chemical composition of the soil solution and matrix at stipulated time increments for each of the soil segments, and the chemical composition of the water entering the water table. Page 4 MOISTURE FLOW PROGRAM INPUTS = WATER APPLICATION & CONSUMPTIVE USE MOISTURE FLOW PROGRAM DATA As previously mentioned, the prediction of the behavior of the soil- water -plant system under field conditions may be considered as beginning with a description of the moisture regime existing in the soil as a first approximation, if the effects of ion exchange, solution chemistry, and microbial transformations on moisture movement are regarded as negligible. The Moisture Flow Program is designed to predict the infiltration, redistribution, plant root extraction, and drainage of soil water under a growing crop so that these properties can serve as inputs to models of the chemical and biological reactions in the "system." Attempts to describe the moisture regime in the soil plant -water system may be arbitrarily divided into two types INPUTS = INITIAL WATER CONTENT & PHYSICAL PROPERTIES OF SOIL 1 OUTPUTS = SOIL MOISTURE CONTENT & MOVEMENT WITH TIME INPUTS = FERTILIZER ORGANIC -N APPLICATIONS, TEMPERATURES, CROP TYPES & BIOLOGICAL CHEMICAL PROGRAM INPUTS = INITIAL CHEMICAL AND PHYSICAL PROPERTIES OF SOIL OUTPUTS = WATER, NITROGEN & SALTS ENTERING GROUND WATER Figure 2. Generalized block diagram of the model. For purposes of modeling, the basic spacial unit is further subdivided into discrete sections as illustrated in Figure I. The Moisture Flow Program employs nodes occurring at equally spaced intervals (OX) numbered downward from the soil surface to an unfluctuating water table. The first node is considered to be at the surface. These dimensionless nodes occur in homogeneous groups of varying numbers defining soil "horizons," which do not necessarily correspond to morphological soil horizons. Soil "horizon" in this context merely refers to a zone of soil which is considered to be homogeneous in certain properties used by the Moisture Flow Program. For the Moisture Flow Program, the soil physical properties are assumed homogeneous in all "horizons." The Biological- Chemical Program utilizes a soil segment concept in which each segment is a length of soil, spacially defined as the distance along the flow line between two or more soil nodes having properties which are the average of nodes contained in that soil segment. A soil "horizon" in the Biological -Chemical Program is a group of soil segments initially considered identical with respect to certain properties, and does not necessarily correspond to a morphological soil horizon. Each horizon and segment is assumed to be homogeneous with respect to certain chemical and physical properties. For the Biological -Chemical Program the physical and chemical properties need not be homogeneous between horizons. Horizons may be variable in size (thickness), while segments all have the same size (OX). Two types of horizons are considered in the Biological- Chemical Program. (1) Chemistry horizons (corresponding to regions within the profile which can be assigned separate sets of soil chemical analysis data). (2) Temperature horizons (corresponding to regions within the profile which can be assigned separate sets of temperature data). Chemical and temperature data for the horizon in which the segment falls are assigned to that segment. Segments which occur across horizon boundaries are assigned data for the lower horizon (Figure 1). By convention a unit cross -sectional area of the flow line is always considered when any system "size" references are made or needed. Thus, the flow line is considered to have a width of rem, a breadth of 1 cm, and to extend from the soil surface to the water table. depending on whether or not individual roots are modeled. If the roots are modeled, the approach may be termed "microscopic," and the moisture flow equation is written in cylindrical coordinates and solved between the root surface and some radius, r = rmax, from that surface. Boundary conditions must be specified in terms of head, moisture content, or water flux at the root and r = rmax. Furthermore, the geometric complexity of the problem increases substantially when more than one root is modeled and two or three dimensions are considered. To overcome these difficulties, a single "typical root" is sometimes modeled and its behavior expanded over the entire soil- water-plant root system by multiplying the average root density (32) . The second approach to modeling the soil water under a growing crop ignores moisture flow to individual roots. "Macroscopic" techniques generally involve the solution of a finite difference approximation to the moisture flow equation including sink (or negative source) term, S. The equation is usually solved in one -dimension for each depth and time step utilizing a numerical technique to solve for the pressure head. In particular, the Thomas tridiagonal matrix algorithm described by Richtmyer (52) is a rapid numerical method reported to "accurately" predict the infiltration, redistribution, and drainage of soil moisture in problems which ignore removal of soil water by plant roots (30, 35) . Recently, Molz and Remson (45) have utilized the Douglas Jones predictor- corrector method to solve the moisture flow equation with a sink term included, but have not considered the addition and redistribution of water applied to the soil surface. Boundary conditions in problems utilizing this macroscopic approach can be specified in meaningful terms, with the upper boundary simulating the soil surface and its properties of infiltration and evaporation. The lower boundary of the system can easily be defined to simulate an impermeable barrier or a water table. Defined in this manner, the macroscopic approach to modeling the system is much more amenable to two- or three -dimensional models than is the microscopic technique. A further advantage of macroscopic techniques is that they permit the use of many types of sub -models to evaluate the sink term S, which can vary in complexity depending on the purpose for which the model is needed. In the most simple case, the term can be viewed as a function of only the overall removal rate (volume of water consumed/total soil profile/unit time) and the depth in the soil ( as fraction of extraction occurring at each depth) (26, 46). The sink term model can be expanded to introduce a hypothetical dependence on the moisture content or pressure head (46), or can involve any of several techniques which have been developed to predict the consumptive use of soil water by Page 5 certain crops under field conditions as functions of variables such as mean daily temperature, percent daylight hours, etc., (5, 26). It is the purpose of this part of the report to describe the development of a one -dimensional digital computer program capable of describing the infiltration, redistribution, drainage, and plant root extraction of soil moisture under a growing crop. The Moisture Flow Program is designed to simulate the moisture conditions existing in the field for periods up to several years in length. Program MOISTRE is the central part of the Moisture Flow Program, as shown in Figure 3. Solution to the moisture flow equation, removal of the sink term, S, and calculation of moisture flux all occur within Program MOISTRE. The soil moisture removal rate by the roots of a growing crop and evaporation ( "consumptive use ") simulated by the macroscopic sink term is evaluated in Subroutine CONUSE. The subroutine utilizes the Blaney -Criddle formula of experimental constants together with the average root distribution with depth in the profile. Two additional subroutines, Subroutine THEDATE ( "the date ") and Integer Function DAY, are called from Program MOISTRE to relate the day number of the simulated run to the calendar date. PROGRAM MOISTRE A general form of the moisture flow equation in one dimension can be written ate = (D ax x K) -S, [1] where 8 is the volumetric moisture content, D is the soil moisture diffusivity, K is the unsaturated hydraulic conductivity, S is a sink term representing volume of H2O consumed /unit volume of soil/unit time, t is time, and x is distance measured downward. ( PROGRAM MOISTRE & INPUT DATA COMPUTE MOISTURE CONTENT AND FLUX FOR EACH DEPTH NODE AND TIME STEP (EACH DAY) WRITE ON MAGNETIC TAPE OR PRINT OUTPUT e' At (Bi+1 =Di+1 - Di - + (B, -1 Bi + 9i+i - 8;_1 - 8i /2Ax2 -S, B;_1 2G Kj+ - 2G Ki -1% :i) 1 [2] in which the superscript `i' refers to time, the subscript `j' refers to depth and G is a gravitational term (G = Ox when gravity is to be included ) . Initial conditions supplying the values of 01j, j = 1, Q, where Q is the maximum number of depth nodes and boundary conditions Bit, and 8'Q define a set of Q equations with Q unknowns which can be solved by the Thomas tridiagonal matrix algorithm described by Richtmyer (52) The boundary conditions chosen approximate those existing in the field over a shallow water table. The basal boundary condition approximating the upper limit of an unfluctuating water table is . 8 = constant. [3] This condition permits both upward (negative) and downward (positive) flux at the basal boundary. Three upper boundary conditions are employed at the soil surface to simulate infiltration, evaporation, or zero flux. To determine the appropriate condition, the date and amount of water applications from both irrigation and rainfall are read from data cards. All such applications are assumed to occur on the first time interval of the appropriate day. If water has been added but has not entirely entered the profile, the upper boundary condition is 6 = constant. [4] Stating this boundary condition as a moisture content rather than as a positive pressure head corresponding to the depth of ponded water is not expected to introduce significant error. Warrick, Nielson and Biggar (59), using a finite difference solution in terms of pressure head rather than moisture content found the boundary condition expressed in equation [4] to closely reproduce the infiltration observed under field conditions on a Panoche clay loam near Fresno, California. If both evaporation and plant uptake of soil moisture are to be simulated by the sink term, S, and no water remains at the soil surface to infiltrate, a zero flux upper boundary condition is employed. This restriction can be approximated START MOISTURE FLOW PROGRAM READ CONTROL A finite difference approximation of equation [1] is (EACH HALF -MONTH) as SUBROUTINE COMPUTE CALENDAR DAY NUMBER -D THEDATE ao +K=O,x=O. [5] DATE FROM If no crop is growing in the system to be simulated, the sink term, S, may be set equal to zero and evaporation from the surface predicted to occur at some rate R by the relationship SUBROUTINE CONUSE -D COMPUTE VALUE OF MACROSCOPIC SINK TERM a +K =- R(R >O,x =O). [6] The moisture flux between adjacent nodes is calculated for each time interval, At, according to the relationship STOP MO STURE FLOW PROGRAM FLUX Figure 3. Generalized block diagram of Moisture Flow Program. = [K1 + %= - -1,i Di+ 1 ( 9, +1 + 91 and the flux rate (cm /day) is defined Page 6 1 - 8; - 20x 83 -1 fit, [7] FR = FLUX volume of soil/unit time) simulating transpiration, evaporation or evapotranspiration is proportional only to depth in the soil and an overall extraction rate U (volume of water consumed /entire soil profile /extended time period). This overall rate U is assumed to be constant for semi -monthly periods and may be measured or estimated for various crops under field conditions. This technique is perhaps the most simplified method of approximating the moisture removal rate and is most useful in cases where the total extraction rate, U, is known to a sufficient degree of accuracy for the problem under consideration. The second technique of evaluating the sink term, S, uses the Blaney -Criddle formula (28) to estimate the total extraction rate, U, due to crop consumptive use [8] At For each time interval the largest flux rate occurring between adjacent nodes is used to define the size of the subsequent time interval. In this way computer expenses are minimized by defining the time interval as the length of time required for a certain amount of water to move in the soil. The defining relationship is taken from Hanks and Bowers (35) +1 - 0.035FR' OX [9] where FR' is the largest value of FR occurring in the previous time interval. The size of the time interval is sometimes reduced so that the Program MOISTRE can write output values for the Biological- Chemical Program on magnetic tape at exact 0.1 day intervals, or enable a specified amount of free water to infiltrate from the soil surface. For cases in which the flux rate is slow, i.e., FR < 17.5 cm /day, the time interval is set equal to 0.01 day (14.4 minutes).* Single-valued relationships for soil moisture diffusivity, D, and unsaturated hydraulic conductivity, K, as functions of moisture content, 8, are necessary. For each time interval, values of D(0) are calculated from an estimate of the moisture content that will exist at the end of the next time interval as suggested by Hanks and Bowers (35) and averaged over two depth nodes. The relationship used is U - 6; +1) + 0111 + Y(01 -1- 01 -2) + [10] 2 where Y is a weighting factor defined Y = 0.7 + ( Ati -1 ). [12] where U is the volume of water consumed/entire profile/ time period, K is the consumptive use coefficient for a particular crop for the time period, T is the mean temperature in degrees Fahrenheit, and P is the percent of annual daylight hours occurring in the time period and 2.54 is the conversion from inches to cm. Values of K, T, and P determined under field conditions at various locations for many crops are available for semi -monthly periods (5, 18, 28). Utilizing either of the two techniques described above to obtain a numerical value of the total extraction rate, U, for a given period of time, the value is reduced to a daily basis and distributed throughout the soil profile in proportion to a constant extraction pattern, such as average effective root distribution, by the relationship 6; + =i2 Y(Bi +i - (K) (T) (P) (2.54)/100, S; [11] The conductivity function, K, is also assumed to be constant over the time interval, but is evaluated on the basis of the moisture content that exists at the start of the time interval and averaged over two depth nodes. Printed output from the Moisure Flow Program summarizes the moisture movement and verifies that the daily leachate calculated from summing the flux between the lowest two nodes is equal to the leachate calculated by mass balance considerations. Output from the Moisture Flow Program to be used as input to the Biological -Chemical Program ** is written on magnetic tape at intervals of 0.1 day. This output consists of the moisture content at each node, the flux at the upper and lower boundaries, the net flux between adjacent nodes and the consumptive use at each node for the 0.1 day period. SUBROUTINE CONUSE At the present time, the model utilizes two methods of evaluating the moisture removal rate S. The first of these assumes that the rate of removal (volume of water /unit (KP) (DEL) iN PERIOD) [I[DAYS [13] where Si; is the volume of water consumed/unit volume of soil/unit time for each depth node (j), KP is the fraction of total extraction (effective roots) occurring in the foot of soil in which node J occurs, and DEL is the length AX expressed in feet. The values for KP, the percent of total extraction occurring in each successively deeper foot of soil were obtained from Erie, French, and Harris (28) or may be supplied by the user as input to the program. This approach assumes a constant withdrawal pattern; i.e. constant effective root distribution, and is expected to provide satisfactory estimates for many row crops, perennial crops, perennial native vegetation, and extraction patterns predicting evaporation only. Although both techniques of evaluating S assume this constant extraction pattern, the model could be easily changed to include extraction patterns varying with time if feasible models of root growth were available. At low moisture contents, the value of the moisture removal term, S, may be reduced to prevent the removal of soil moisture below some specified moisture content. This reduction of the sink term at any node simulates the point below which the roots of the growing crop are unable to extract soil moisture. If this point is reached at any node *Limiting the maximum size of the time increment, At...,..., to 0.01 day is expected to adequately compromise the requirements for an accurate but rapid solution. In certain cases; i.e., for course materials or studies in which the response of the model to At /.ßx2 is more closely examined, it may be possible to increase the value of atm9 =;mum. * *A separate interface program must be used to convert from nodes to segments before the Biological- Chemical Program can use this data. Page 7 in the profile, the amount of moisture which is predicted to be extracted but which is "not available" is computed as "deficit moisture." The moisture removal term, S, in the moisture flow equation can have different interpretations depending on the system which is to be simulated. If the system does not include a crop growing in the soil, the moisture removal term can be used in two ways to simulate evaporation from the soil surface: (a) The sink term, S, can be assumed to be zero and evaporation predicted by a flux boundary condition, or (b) The sink term, S, can be assigned a value and withdrawn from the second depth node (OX below the soil surface) while a zero flux boundary condition is maintained at the soil surface. If a growing crop is included in the system to be modeled, the moisture removal telut can be used in two similar ways:* (a) The term S can simulate plant root withdrawal at each depth node below the soil surface and evaporation can be predicted by a flux boundary condition or, (b) The withdrawal term S can simulate the total evapotranspiration withdrawal by the crop and root distribution can be weighted so that evaporation is simulated from the uppermost depth nodes while a zero flux upper boundary condition is maintained. SUBROUTINE THEDATE AND INTEGER FUNCTION DAY Subroutine THEDATE ( "the date ") is called from Program MOISTRE to calculate the calendar date from the day number relative to Jan 1. Called on a daily basis, THEDATE is used to determine when Subroutine CONUSE should be called (first or sixteenth of each month). Integer Function DAY is a subroutine that returns a single integer value corresponding to the Julian date from the calendar date. It performs the converse of Subroutine THEDATE so that water applications can be scheduled on the correct day number of the run. For periods up to one year, the Julian date is the same as the day number. VERIFICATION OF MOISTURE FLOW PROGRAM The Moisture Flow Program was designed to predict the behavior of certain soil moisture properties so that these properties could serve as inputs to models of the biological, chemical, and physical processes occurring in the soilwater -plant system. Experimental verification of each soil moisture property was impossible because of temporal considerations, and partially unnecessary because many of the theoretical or empirical components of the Moisture Flow Program had been verified in the literature. The cumulative infiltration is an important and easily verified property predicted by the model. Single-valued relationships for unsaturated hydraulic conductivity, K, and soil moisture diffusivity, D, as functions of moisture content, 0, were obtained from data of Warrick et al, (59) on Panoche clay loam collected from the Fresno area of California. An additional relationship was defined empirically to extend these properties over the range from O = 0.07 to 8 = 0.15. The relationships presently being utilized are K(cm/day) - 4.7 x 10-5x D(cm2/day) = 2.7 x 104 for 0.38 > O > 0.36, D(cm2/day) for 0.36 = x exp(35.80), [14] exp(-0.90) [15] 6.3 x 10-1 x exp(25.30) > O >15, D(cm2/day) = 6.2 x 10-4 x [exp(35.80 0.236/0]/02 for 0.15 > 8 > 0.07. [ 16] [ 17] Comparisons with field observations of cumulative infiltration made by Warrick et al, (59) on Panoche clay loam at the University of California Westside Field Station are shown in Figure 4. Figure 5 shows calculated changes in the moisture profile occurring when moisture is added to a profile which is dry at the surface yet saturated at the base due to the presence of an unfluctuating water table at day 166.0. At the first time interval of day 166, 12.8 cm of water was added simulating a scheduled irrigation. At 1.66.1 days the moisture front had reached a depth of approximately 25 cm, and at 166.2 days a depth of 45 cm. By 166.3 days all of the moisture had infiltrated and the soil surface began to dry out due to plant consumptive use withdrawal. As the soil continued to dry, the moisture profile continued to redistribute until at 166.4 days only a diffuse wetting front was present. To insure that the Moisture Flow Program was selfconsistent with respect to conservation of mass, a check was constructed to compare the leachate predicted by summing all flux between the bottom two depth nodes with that predicted from Leachate = (Moisture added) (Plant consumptive use) (Change in storage). This comparison showed the Moisture Flow Program to be self-consistent within 0.17% of the total moisture added. - - BIOLOGICAL- CHEMICAL PROGRAM The chemistry of soil -water systems is extremely complex and involves principles drawn from many disciplines of science. Any reasonable chemistry model should incorporate and relate the important chemical reactions and principles associated with the system as defined. The Biological- Chemical Program combines independently derived relationships for many important biological and chemical processes occurring in soil -water systems. Although not all important processes (e.g. those associated with sulfur and phosphates) are included in this model, it does include many processes of interest in soil-water chemistry and related disciplines. Research (39) has shown that reactions (transformations) involving nitrogenous species (e.g. organic -N, NH +4 -N, urea -N, NO -3-N, etc.) are significant in soil water systems. In the areas of pollution control, soil fertility, and plant nutrition, nitrogen transformations are of great interest. Various mathematical models describing these reactions have been developed using reaction kinetics (43, '`The sink term, S, is not removed from the uppermost depth node in order that the desired flux condition may be maintained at this boundary. This requirement results in a displacement of the effective root distribution but no error in total withdrawal if the depth of the profile is at least OX cm greater than the depth of the roots. Page 8 The kinetic approach was applied here because reaction times involved in microbial nitrogen transformations are on the order of days or weeks. That is, the reaction rates and states of the system along the reaction pathway are of interest to the observer. This model incorporates rate equations for transformations such as hydrolysis of urea, mineralization- immobilization of organic -N and NH +4 -N, nitrification of NH +4 -N and immobilization of NO-3 -N. In addition to nitrogen transformations, researchers (23) have found that reactions involving ion exchange, solution -precipitation of slightly soluble salts, and formation of undissociated ion pairs are important in soils. Since the reaction times involved in these processes are on the order of seconds or minutes (34), equilibria principles have been used in the derivation of descriptive mathematical relationships (21). Here the reaction times are so rapid that the observer is interested only in the initial and final states ( e.g. equilibrium) of the system at a point in space and not in the states along the reaction pathway. This model uses equations for the processes mentioned above based on principles of steady state equilibria. Movement of soluble species (e.g. Ca", Na +, Cl -, etc.) by water flow has been studied by various researchers (25, 50, 57), and has been shown to be closely interrelated with chemical processes in the system (24) . However, the assumption may be made that water flow and content are independent of chemical processes, but chemical processes are dependent on water flow and content (24) The mixing cell concept (42) may be employed together with moisture flow data to simulate solute dispersion and movement in the system. Dispersion is defined here as a physical or mechanical (not a chemical) mixing process encompassing two 44, 53). . 40 Panoche - Loam X-measured at U.C. Westaide Field Stotion predicted by Moisture Flow Program 30 20 10 00 0.2 O.1 0.3 0.6 0.9 1.0 specific processes. The first is mixing caused by molecular diffusion. This process is important in soil -water systems only when water flow rates approach the rates of diffusion, e.g. when little or no water movement occurs (4). Under most circumstances, the assumption may be made that the diffusion process produces negligible effects on the soilwater system. The second process includes mixing due to tortuosity and /or turbulence associated with the pore spaces. This important process is simulated by the use of 0 .20 .24 .28 .32 .36 10 .04 .08 CONTENT .12 .16 .20 IO 166.0-> 0.7 time. 0 .04 A8 20 00 Figure 4. Predicted and observed cumulative infiltration with MOISTURE .16 0.5 TIME ( day ) MOISTURE CONTENT (cm3/cm3) .12 0.4 166.1 20 30 30 40 40 50 50 60 60 70 70 80 80 90. 90 100. 100 110 110 120. 120 130. 130 140, 140 150 150 Figure 5. Moisture profile changes as 12.8 cm of water is applied at day 166.0. Page 9 . ( cm3 /cm3) 4 . 8 .32 .36 mixing cells and moisture flow data at each increment in time and space. The assumption is made that complete mixing occurs at each increment. Since flow rates vary while space and time increments generally are kept constant, the program produces less mixing at faster flow rates. This phenomenon has been observed experimentally (24). Research (38) has indicated that nitrogenous chemical forms taken up by plants are primarily NO-3 and NH +4. In most cases nitrate is the predominate of the two forms. Also, research (28) has shown that nitrogen uptake tends to be proportional to root distribution. Some evidence exists (28) which suggests nitrogen uptake may be related to water uptake. The program provides the user with two methods for simulating plant nitrogen uptake. With the first, total plant -N uptake and root distribution are used to estimate plant -N uptake from each soil segment /Otime. The user selects the fraction of nitrogen uptake which is nitrate, the remainder being ammonium. The second method involves the use of plant -water uptake data (e.g. supplied from the Moisture Flow Program). The assumption is made that uptake of nitrate and ammonium is proportional to water uptake. The proportionality constant must be supplied by the user. A generalized block diagram of the Biological-Chemical Program appears in Figure 6. The program consists of three major control routines (MAIN, EXECUTE, and COMBINE), four computational subroutines (TRNSFM, XCHANGE, FL, and UPTAKE), and several miscellaneous subroutines. The program predicts, with time, the concentrations (or masses) of chemical species in an unsaturated soil -water system (along the flow line previously discussed) . In addition, the model predicts concentrations (or masses) of chemical species leaving the system (i.e. leached or removed by plants). Program execution takes place in the order indicated in Figure 6. Program MAIN reads in control and input data, and stores it in forms convenient for program execution. In addition, MAIN may be instructed to print a record of these inputs. Subroutines EXECUTE and COMBINE control the execution of the computational subroutines for each time and depth increment, respectively. Subroutine EXECUTE makes any fertilizer and /or organic matter applications to the soil on a daily basis. In addition, soil temperatures are updated weekly. EXECUTE reads moisture flow data from Program MOISTRE* or uses data read from cards, and calls Subroutine COMBINE for each time step within a day. COMBINE, in turn, calls the computational subroutines for each soil segment, sums the predicted changes in mass returned by these subroutines, and updates the mass values in storage for each segment. Also, COMBINE prints or writes the various output data as requested. The mass changes returned to subroutine COMBINE are computed with respect to the various processes being modeled (i.e. nitrogen transformations (TRNSFM), - ion exchange and solution -precipitation reactions (XCHANGE), plant uptake of N (UPTAKE), and water movement of soluble species (FL) ). All changes for a time step and any one soil segment are based on the same set of data. This means that each process is independent over a time step with respect to availability of component masses. The assumption is made that the rate of change for each *Following conversion of data from Tape 5 (START BIOLOGICAL CHEMICAL PROGRAM - PROGRAM MAIN READ CONTROL AND INPUT DATA STORE INITIAL SOIL -CHEM DATA PRINT CONTROL AND INPUT DATA (OPTIONAL) SUBROUTINE EXECUTE MAKE ANY FERTILIZER AND /OR ORGANIC MATTER APPLICATIONS INITIALIZE OR UPDATE SOIL TEMPERATURES (WEEKLY) (EACH DAY) READ MOISTURE FLOW DATA FROM MAGNETIC TAPE EACH TIME STEP WITHIN A DAY) SUBROUTINE COMBINE FOR EACH SEGMENT: CALL EXCHANGE SUBROUTINE CALL NITROGEN SUBROUTINE CALL SOLUTE REDISTRIBUTION SUBROUTINE CALL PLANT -N UPTAKE SUBROUTINE SUM CHEMISTRY CHANGES AND UPDATE VALUES IN STORAGE PRINT OR WRITE SPECIFIED VALUES STOP BIOLOGICAL -) CHEMICAL PROGRAM Figure 6. Generalized block diagram of Biological- Chemical Program. component mass is constant over a time step. In the present version of the model, ten time steps (increments) per day are used in making the above assumption except that the program will increase the number of steps to a user supplied value for that 0.1 interval if a nitrogen deficiency is detected in some soil segment. If the assumption is valid, the mass changes become numerically integrated over time yielding predicted masses (or concentrations) in each soil segment for each time step. SUBROUTINE XCHANGE The equilibrium subroutine (XCHANGE) considers chemical reactions in base saturated soils which are known to effect the solute composition of percolating waters. These include ion exchange and the solubilization or precipitation of slightly soluble salts. To calculate the changes in solute composition due to these processes as moisture moves from segment to segment along the flow line (Figure 1), it has been assumed in the model that the reaction rates of ion exchange, solubilization or precipitation of slightly soluble salts and dissociation of soluble ion pairs are much greater than the rates of water format (Moisture Flow Program output) to Tape 1 format (Biological-Chemical Program input). Page 10 movement and nitrogen transformations. It is further assumed that the water entering a segment will equilibrate with any remaining solution, the slightly soluble salts, and exchangeable ions on the exchange complex. This subroutine is designed to predict the equilibrium solution which would result within the segments under the assumptions stated in the previous paragraph. A simplified block diagram of the subroutine is shown in Figure 7. It will be noted that Subroutine EQEXCH is called on the initial pass for each of the soil segments considered. As will be seen later, Subroutine EQEXCH calculates the initial concentrations of exchangeable ions present in each segment. In essence, as indicated in Figure 7, a method of successive approximation is utilized to solve the various equations in Subroutine XCHANGE. The solution is reached when all the equilibrium constants of the various reactions are satisfied. In keeping with the Gibbs phase rule, for every new constituent added to the system, a mathematical relation relating the constituent to other constituents in the system must be added to the model. Also, there must be one more mathematical relationship than components in the system. The constituents of Subroutine XCHANGE and their mathematical relationships are discussed below. if added, or when the solubility product (see below) is exceeded. An equation relating gypsum to other constituents in the soil is CaSO4 x 2H2O = Ca++ + 50=4 + 2H2O [18] This reaction has been considered in an earlier model (21) The equation for calculating equilibrium concentrations for equation [18] in soil -water systems from initial concentrations or approximations of the constituent concentrations . is X2+BX+C=O where X [19] = change in concentration of Ca ++ and S0 =4 to reach equilibrium, B = C'ca + C504. Here C' is the initial or approximation of the ion concentration indicated by the subscripts, and C = C'Ca C's04 - Kv/y22 where Ks0 is the solubility product (2.4 x 10 -5), and 72 is the divalent activity coefficient (discussed below). Solubility and Precipitation of Gypsum: A slightly soluble salt often present or added to soils CaSO4.2H20. It is considered in the model, is gypsum, Undissociated Ca and Mg Sulfate: The chemistry of undissociated CaSO4 and MgSO4 in solution is similar, thus they will be discussed together. The chemical reactions taking place in water are ENTER al CALL EQEXCH CaSO4 :17. Ca++ + SO-4 [20] MgSO4 2-7. Mg++ + 50-4. [21] (FIRST TIME) / CALCULATE CaCO3 SOLUBILITY CONSTANT AT These reactions have been considered in previous models (20, 55 ) and the stoichiometric relationships and derivation of an equation to calculate the equilibrium concentrations can be found in the above papers. The equation used in the subroutine under discussion is SPECIFIED MOISTURE CONTENT CONSIDER SOLUBILITY REACTION CaSO4 + Ca ++ SO4 + x 2H2O= 2H2O i CONSIDER UNDISSOCIATED ION PAIR REACTION =Ca" CaSO4 + AX2 + BX + C SO4 -0 [22] y 1 CONSIDER THE 2Na+ + where X EXCHANGE REACTION Ca-Rs Ca" + 2Na -R i CONSIDER EXCHANGE REACTION Mg" + Ca -R xCa ++ and Ca ++ or Mg' concentrations to reach equilibrium, = the change in S0 =4 A = 722 B = Mg -R + i CONSIDER EXCHANGE REACTION NH4 + Na -R xNa+ + C- t ION PAIR - (KD + y22 Caca or Mg + y22 CSO4) Here KD is the appropriate dissociation constant, and NH4 -R CONSIDER UNDISSOCIATED MgSO4 x Mg" + SOq (the divalent activity coefficient), and REACTION 722 CCa or Mg C504 - KD C'CaSO4 or DIgSO4 When the system contains gypsum, the undissociated t CaSO4 becomes a constant CONSIDER THE SOLUBILITY REACTION + H2CO3 =Ca" + 2HCO3 CaCO3 CCas04 RETURN TO COMBINE IF EQUILIBRIUM CONSTANTS SATISFIED - KsI [23] KD Ca -Mg Exchange: Figure 7. Generalized block diagram of Subroutine XCHANGE. Page An equation which has been used earlier [21] for describing Ca -Mg exchange is incorporated in the model. 11 The equation, the appropriate stoichiometric relationships, and derivation are presented in the above paper. The equation is Ay2 +By concentration of Mg ++ and Ca ++ to reach equilibrium, and Here ß = #(1 - Knig.-ca) = liter of water /g soil, K g-ca constant, and B = ß(N'Mg + KM1g -Ca N'Ca) = Ca -Mg exchange + C'ca - KMg Ca Dissociation of CaCO) in Water: C'Mg =0 [25] change in concentration required to reach equilibrium from initial or approximated conditions, = aCa aCO3, H2CO3 - 4K2cu D = N'Na Y% (4 C'Ca + N'Na /3) + N'Na ß) Na /3 where = aCa a2HCO3 It may be shown that = K N'ca 2K2Ca-Na N'Ca C'Na (2ß N'c.a + C'Na), and E= N 2 Na C' ca C Ca y1/.a - K Ca Na C2 Na C i2 K5"Ki The exchange reactions involving sodium and ammonium are similar to Ca -Mg exchange. The equations are the same except the exchange constant Kea-mg is different, and Na+ and NI-1+4 replace Ca and Mg' the equations. Activity Coefficients: Debye- Hückel Theory has been utilized in the model to calculate activity coefficients. Discussions of the theory can be found in textbooks (34) The equation used to calculate single ion activities is . = -.509 z2 µ'A 1 [31] K2 K' K Cn2co3 Y21 Y2 Y21 Y2 - Cca C2HCO3 [32] where y1 and y2 are the activity coefficients for monovalent and divalent ions respectively (discussed earlier) and C is the equilibrium concentration of species indicated by the subscript. The stoichiometric relations Oa Ca -Mg and Na-NH,, Exchange: log y; [30] aE32co3 B Na, (ßNi ca+2CNa)-KCaNaC 2C Na) + [29] where K1 and K2 are the first and second acid dissociation constants for H2CO3. Provided an equilibrium system is under a constant pressure of CO2 and activity of an uncharged species is taken as unity, equation [30] becomes . Here y% is a ratio of activity coefficients. (C'Ca [28] + CaCO3 %Ca" + 2HCO-3, A = 4Yvz [27] where a is activity of the ion designated by the subscript. The C0 =3 concentration is a function of the CO2 partial pressure. HCO -3 is usually the predominant form in which CO2 occurs in soil -water systems. Thus, it is more convenient to consider the following reaction K = the + CO -3, and the thermodynamic solubility product, Ks ", is Ks, The Gapon [31] equation was used to describe Na -Ca exchange. The derivation is similar to that in the literature [23], but the stoichiometric relations are substituted into the Gapon equation. The equation for calculating equilibrium conditions is = -4 K2ca-Na ß2, and B = 4ß (Y3, + 2K2ca-Na N'ca ß + K2ca-Na C'Na ) Ca" CaCO3 Ca -Na Exchange: C =1 Here n is the total number of ion species present in a soil solution. Since all ions considered are monovalent or divalent, the model considers only these two activity coefficients. C= Cot N'n1g - Kca aig C'Jlg N'Cca where X C, z2;. 1 The dissociation of CaCO3 in water is usually shown as where N' is an approximation of initial concentration of the exchangeable ion indicated by the subscript and AX4 + BX3 + CX2 + DX + E in question and i 11 J =V2 [24] = change in where y A +C =O where z designates the valence of the ion Ceti CHCO3 =C'ca+Z [33] = C'nco3 + 2Z [34] where C'ca and C'HCO3 are the concentrations before equilibria existed or approximations of the concentrations of Ca +2 and HCO -3 respectively, and Z is the change in moles to reach equilibria, may be substituted into Equation [32] to yield the equation [26] + µ% Page 12 AZ3 + BZ2 + CZ + D = 4.0 B = 4.0(C'r1c03 + C'ca), A = 0.0 [35] C = C'2H003 + D = 4.0 C'ca C'2Hco3 C'ca Results and Discussion: CHCO3 - K'/y21 'Y2 Equations [33], [34], and [35] are used to calculate the equilibrium concentrations of Ca +2 and HCO -3 when they are included in the subroutine. Calculating Changes in CaCO3 Solubility with Changing Moisture Content in Soils: In the development of models for predicting the behavior of calcareous soil -water systems, it became necessary to develop equations which described the reactions of CaCO3 in the soil -water systems at various moisture levels. These reactions have received the attention of investigators at the USDA Salinity Laboratory (11), who have considered the soil as a closed system in which the CO2 partial pressure is constant. Also, Dyer (27) found that under conditions where the partial pressure of CO2 was known, the reaction of CaCO3 could be described in soil-water systems. The above investigators either oversimplified (for some applications) or required information beyond present data capabilities. With this in mind the following research was conducted. As previously mentioned, if a constituent is to be added to a system, an expression describing its interaction with the system must be known if the system is to be described at equilibrium. A convenient reaction to consider which fits the above criteria is shown in equation [29]. If it is assumed that at a given moisture content the H2CO3 concentration is constant at equilibrium (this is equivalent to assuming a constant CO2 partial pressure at a constant moisture content) and the usual convention that the activity of a crystalline solid is unity, equation [30] becomes K' = aca.. a2Hco3 [36] The values of K', equation [36], were calculated for each of the soils at each moisture content using the procedure indicated above. It was found that a plot of log M, where M is the percent moisture, against log K' yielded a nearly linear relationship (Figure 8) Simple linear regression analysis was used to determine the equation of the best fit line and the correlation coefficient, r, and standard deviation, s, were calculated for each soil. The values for slopes of the lines, the intercepts, r and s are given in Table 1 for each soil. . TABLE Soil 1 2 3 4 5 6 Values of the Slope, Intercept, Correlation Coefficient (r) and Standard Deviation (s) for the Least Squares Line for each Soil. 1. Slope -1.886 -1.627 -1.636 -1.707 -1.645 -1.590 Intercept r -4.249 -4.588 -4.419 -4.430 -4.454 -4.606 s 0.999 0.992 0.999 0.998 0.999 0.997 0.001 0.106 0.028 0.044 0.020 0.056 o It has been pointed out in the literature (47 ) that the solubility product of CaCO3 in the soil is different from pure calcite, and also the H2CO3 content would be expected to vary with different soils and moisture contents. The concentration, C, of Ca ++ and HCO -3 can be determined from the soil extract, assuming that the activity coefficient, y, can be calculated by equation [26] then equation [36] can be used with the concentration from the soil analysis to determine K'. If the value of K' is determined at several moisture contents it would then seem possible to determine the functional relationship between K' and moisture content. a 6 -fsOU s011 s a 4 4-SOIL Log Experimental Procedures: SOIL -4-SOIL so Ii I M Figure 8. Plot of log K1 vs. log moisture percent. Calcareous soil samples were collected from the A horizons of six different soil series in Southern Arizona. Sub samples of each of the above were equilibrated overnight in closed containers at the saturation percentage, 100 percent moisture and 500 percent moisture and an extract of each was obtained by suction. The extracts were analyzed for Ca", Mg", Nat, SO -,}, Cl -, HCO-3, and C0 -3 by the Soil and Water Testing Laboratory of the University of Arizona. The equation of the line including all six soils at all three moisture levels is Log K' = -1.68' Log M -4.46. [37] The correlation coefficient for equation [37] was 0.988 and the standard deviation was 0.131. It appears from the Page 13 data presented here that equation [37] is a useful equation for predicting the solubility of lime. It is used in the subroutine under discussion here to predict when CaCO3 will appear and behave in a soil system when CaCO3 was not originally present. The points for each of the three moisture levels for each soil have been connected by lines in Figure 8. It would appear by observation that a better representation than equation [37] for any one soil would be parallel lines with the same slope as the regression equation. In practice the equation of the line for each soil would have to be based on a value of K' at a known moisture content. Thus, based on the value of K', percent moisture and slope, ( -1.68 for each soil at the saturation percentage), theoretical values of K' for the 100% and 500% moisture were calculated. The values, theoretical and actual, of Log K' at all three moisture levels and for all of the six soils were treated as paired data. It was found that the correlation coefficient for the predicted values and the point of reference at the saturation percentage when paired with the experimentally determined values was 0.991. The standard deviation for the above was 0.111. The correlation coefficients and standard deviations for the soils at all three moisture contents are given in Table 2. TABLE 2. Paired Comparison of Measured and Pre dicted Values of Log K' for each of the Soils* Soil 1 2 3 4 5 6 r s 0.999 0.993 0.999 0.998 0.999 0.997 0.002 0.109 0.029 0.044 0.020 0.059 water systems; these are undissociated CaSO4 (20) and MgSO4 (56). Thus, the total sulfate in solution would be C304T = C504 + CCaSO4 + Similarly, the total Ca, CCaT, and Mg, CMgSOç. CMgT [38] would be CCnT = Co, + CCaSO4, [39] CMg'l' = CDíg + CMgs04. [40] The thermodynamic equilibrium constant, K, for equilibrium between the undissociated species in solution and the appropriate ions would be KCaS()4 = KMgso4 = ac, aso4 [41] aras04 aMg asO4 [42] aMgso4 Combining equations [39] and [41] it is found that CCaSO4 = Yso4 Yda CCaT C504 KcaSO4 + [43] yCa Ys04 C504 and similarly combining equations [40] and [42] that Yso4 Yníg CMgT C504 CMgsO4 = K1SgSO4 + [44] yMg YS04 CS04 Combining equations [38] [43] and assuming the divalent activity coefficients (y) are equal it is found that AX3+BX2+CX+D=0 *K' calculated from saturation extract data. = C504, A = Y22 = ( Yca y504) _ ( YMg Yso4 ) B = Y2 [(Kcaso4 + Knígso4) + y2 [45] where: X It should be pointed out that the moisture contents of the above investigation are higher than one encounters in the field. It is assumed in the subroutine that the same relationships hold in the field moisture range. (Cníg'r C SUBROUTINE EQEXCH This subroutine calculates exchangeable ion concentration from initial soil analysis. In an earlier model by Dutt and colleagues (25) describing soil -water systems, an approximation method was used to calculate the exchangeable Na +, Ca", and Mg". Although this method gives values which are adequate for many applications, it did not take into account the interactions of sulfate with cations. Thus in some cases where sulfate was involved, changes in ion composition of the soil solution would be predicted when in fact none could occur. Since the concentrations of these exchangeable cations are necessary to predict changes in soil solute composition and reliable analytical methods are not available to determine all of their values in calcareous soils, an improved method for their calculation was necessary. + = Kcaso4 KMgso4 + 72 [CMgT Kcaso4 (KCaSO4 D CCaT = + , - Cso4T) J + CraT Kaígs04 KMgs04) J -Cso4T Kaígso4 KrasO4. CSO4T , Utilizing the activity coefficient for divalent ions and equations [38], [39], [40], (43), [44] and [45] the concentrations of Ca ++ and Mg ++ can be calculated. A generalized block diagram of the subroutine for performing these calculations is shown in Figure 9. An equation that has long been used to describe Ca -Mg exchange (20) is ara K í NCa amg NMg [46] where N denotes the concentration of the exchangeable ions indicated by the subscript. For Na-Ca exchange the Gapon equation which has been exhaustively tested is Theory: Sulfate occurs in basic solutions in more than one form. In addition to the sulfate ion, there are two forms which have been shown to be of importance in base saturated soil- Page 14 aNa YaCa _K 2 Nva Nca [47] 3 The above data were also treated as paired data. Table gives the slope, correlation coefficients, and standard deviations. ENTER TABLE 3. Correlation Coefficients (r), Slopes, and Standard Deviations (s) for the Regression Lines, Through Calculated and Measured Val ues of Exchangeable Ca", Na +, and Mg". ) CALCULATE IONIC CONCENTRATIONS OF Ca + +, Exchangeable Ion Ca" Mg ++ AND SO4; AND CONCENTRATIONS OF UNDISSOCIATED CaSO4 AND MgSO4 IN SOIL EXTRACT CALCULATE EXCHANGEABLE Ca + +, Mg + +, Mg++ Na+ RETURN TO EXCHANGE and Mg', = NNa + Nmg + Nca. Na+ [48] Combining equations [46], [47] and [48] it is found that Nca = NT acá K2 K1 anlg aNa aca + 1). [49] Knowing the activity coefficients, the ionic concentrations for an equilibrium soil extract for Ca', Mg', Na +, and the total exchangeable bases, the exchangeable Ca ++ can be calculated using equation 49. The exchangeable Na+ can then be calculated from equation [47], and finally the exchangeable Mg from equation [48]. For practical calculations, the exchange capacity is taken to be equal to NT. Ammonium is known to be exchanged with other ions in soil water systems. An equation that has been used to describe ammonium exchange is CNH4 CNa =K NNH4 o 0.999 0.999 0.996 1.02 0.953 1.20 0.126 0.082 0.068 SUBROUTINE TRNSFM Figure 9. Generalized block diagram of Subroutine EQEXCH. NT s The correlation between the observed values and calculated values indicates the procedure for calculating the exchangeable ions is of use here. CSUBBOUTINE Ca', Slope Na +, AND NH4 The total exchangeable, (NT), would be r Nitrogen transformations have been the subject of numerous publications. Researchers (2, 7, 10, 17) have investigated various reaction pathways and mechanisms involved. The literature contains many data sets relating to these transformations. A few attempts (40, 43, 44) have been made to construct mathematical models describing some of the reactions. As previously indicated, these models have involved a kinetic approach due to the relatively long reaction times involved. A similar approach involving kinetics was used to develop the nitrogen transformation subroutine (TRNSFM) . First, concepts of system analysis were used to define and limit the system and establish pertinent variables and reaction pathways. Next, rate equations based on these basic variables were developed using computer oriented statistical analyses together with other information. Subroutine TRNSFM interconnects the transformation pathways derived from the systems analysis and [50] NNa 30 25 a. The value of K. was found to be from 0.17 to 0.3 for four California soils (41). Since this is a relatively narrow range, the average of 0.22 is used in the model. The model also assumes the concentration of NI-1+4 is negligible compared to NT. Thus equation [50] is used directly to calculate exchangeable NH +4. Verification of Subroutine EQEXCH: The data of Paul, Tanji, and Anderson (49 ) were used to test the subroutine. Their data include chemical analysis of extracts and exchangeable ions for five California soil series (Arbuckle, Hanford, Oakley, Yolo, and Sacramento). A plot of the measured values for exchangeable Ca', Mg", and Na+ against calculated values (using the procedure indicated here) is shown in Figure 10. Page 15 5 10 15 MEASURED EXCNANGE PERCENT meq. g. 20 /100 Figure 10. Calculated vs. measured exchange percent for Ca ++ Mg ++ Nat 25 quantified by the rate equations. The subroutine models urea hydrolysis, mineralization -immobilization of NH +4 -N and organic -N, nitrification of NI+4 -N and immobilization of NO -3 -N as a function of component concentrations, temperature, C:N ratio, and soil moisture content. The subroutine solves for net changes in mass for urea -N, NH4 -N, organic -N, and NO3 -N over a time step for each soil segment. The independently derived rate equations are solved simultaneously by a numerical integration procedure which partitions a time step into successively smaller steps until nearly identical results are obtained for the mass changes over the original time step. These predicted mass changes are then returned to subroutine COMBINE. Systems Analysis: After a thorough review of the literature, the system was restricted in scope by establishing certain limitations and assumptions selected on the following basis. The minor and /or extremely complex parameters were excluded but enough important ones were included to allow field applications of the completed subroutine. Next, the restricted system was subdivided into various biochemical and chemical pathways within the soil pertaining to nitrogen. Based on these routes, pertinent inputs and outputs were designated for the system. Finally, pertinent variables were established which applied to the transformation pathways. Limitations and Assumptions: The following limitations apply to the soil -water system considered by this subroutine. 1. The system is restricted to alkaline soils. Many other soil reactions concerning nitrogen take place primarily under acid conditions. This limitation serves to simplify the chemistry but still includes most soils of arid regions. 2. Within the subroutine, only nitrogen transformations are predicted. The leaching of nitrogen chemical forms is left to Subroutine FL. Uptake of nitrogen by crops is excluded from the subroutine ( see Subroutine UPTAKE) . 3. The soil moisture content is limited to a range bounded approximately by field capacity and permanent wilting point. The following basic assumptions were made to further simplify the system. 1. Gaseous losses of nitrogen are negligible. This assumption is valid when aerobic conditions exist in the soil, and urea and ammonia fertilizers are not applied on or near the land surface (14, 15, 29, 33). The assumption would not hold in cases such as bog soils where restricted aeration exists, or in cases where ammonia is easily lost as a gas. 2. The soil pH remains in the range 7.0 to 8.5. The effect of hydrogen ion activity on soil nitrogen transformations is approximately constant in this interval (1, 17) 3. Symbiotic and non- symbiotic N fixation and fixation of NH +4 -N in clay crystal lattices are small in magnitude by comparison with other nitrogen transformations considered in this subroutine. 4. NO -2 -N does not accumulate in the soil beyond trace amounts. 5. Fertilizers and other N additions are applied uniformly and thoroughly mixed with the soil. 6. The microbial populations of different soils are approximately equivalent in their responses to pertinent parameters associated with N transformations. 7. The chemical composition of the soil (other than nitrogen species) has little effect on N transformations. Biochemical and Chemical Pathways: Biochemical and chemical pathways within the soil are combined to include . ORGANIC -N MINERALIZATIONIMMOBILIZATION NITRATE -N IMMOBILIZATION AMMONIA -N NITRATE -N NITRIFICATION UREA HYDROLYSIS UREA-N t Figure 11. Biochemical and chemical pathways of Subroutine TRANSFM. those nitrogen transformations which are performed biochemically by microorganisms or chemically in non -biological reactions, Figure 11. These pathways are in keeping with the previously mentioned limitations and assumptions. They include hydrolysis of urea, nitrification of NH +4 -N, mineralization -immobilization of NH +4 -N and organic -N, and immobilization of NO -3 -N. They represent the major biochemical and chemical nitrogen transformations thought to occur in the restricted soil system. Other pathways are assumed to be insignificant by comparison. Hydrolysis of urea was included because urea is a common N fertilizer added to soils, and hydrolysis is the major reaction occurring with respect to urea in most soil systems. Immobilization of NH +4 -N is important since microbes use NH +4, a common nitrogen type in soils, to form cell material when organic residues with C:N ratios greater than about 23 are added to soils (6, 12) . Mineralization of organic residues is significant at carbon -nitrogen ratios less than about 23 and had to be included as a transformation pathway. Nitrification of NH +4 -N is the primary means by which NH +4 -N is transformed to NO_2 -N and NO -3 -N in soils. It is included as an extremely important pathway. However, microbes may consume significant amounts of nitrate when high nitrate and low ammonium concentrations occur over extended periods of time. Inputs and Outputs: The basic inputs and outputs of the subroutine are illustrated in Figure 12. The central box represents the subroutine, and contains the biochemical and chemical pathways previously mentioned. The surrounding boxes represent inputs or outputs as designated by the directions of the arrows. Nitrogen amendments include urea -N, NH +4 -N, NO -3 -N and organic -N (as organic matter). These nitrogen forms commonly are added to soils either by man or animals, or in precipitation. Also, they are forms which can be handled by the established internal pathways. Together with temperature, moisture content, and initial soil conditions with respect to C and N, they form the basis for inputs to the subroutine. Page 16 bilization pathway were selected in a similar manner. The temperature, moisture content, concentration of NO -3 -N and amount of organic -N were selected as possibilities. Broadbent (7) has shown these variables to be significant in association with NO -3 -N immobilization. NITROGEN AMMENDMENTS Data Collection: Keeping in mind the limitations, assumptions, and basic variables associated with the system, a search of the literature was undertaken to locate useful data. Data of primary interest were those which could be used to develop rate equations for urea hydrolysis, immobilization, mineralization and nitrification. In addition, data were WATER SUBROUTINE -4---TRNSFM INITIAL SOIL CONDITIONS -4 -- EMPERATUREH" NITROGEN CHANGES IN SOIL SEGMENT Figure 12. Inputs and outputs of Subroutine TRANSFM. Subroutine outputs are limited to changes in concentrations (or masses) of urea -N, NI-1+4-N, NO -3 -N and organic -N in a specified segment of the soil/At. Other parameters such as texture, pH, size or species of the microbial population, bulk density, and soil aeration could be included in a future extension of the model. However, they are assumed to be relatively minor factors in the system as defined. Selection of Basic Variables: Based on the literature review and systems analysis a set of basic or working variables was selected for each transformation pathway. These were parameters which could be important in the system as defined. The variables or variable combinations used in the final equations depended on the extent and type of data in the literature as well as their statistical significance. The temperature and the amount of urea -N were selected as working variables for the urea hydrolysis pathway. Researchers (4, 48) have found that soil moisture content, pH, and areation have little effect on the hydrolysis rate. Depth of application would be important only if surface or near surface applications are being considered. Other parameters are probably important but have not been thoroughly investigated. The mineralization and immobilization pathways were studied together as a unit because they are rather closely related. The basic variables selected were the concentrations of organic -N and. NH +4 -N, the temperature, the moisture content, and the C:N ratio of the organic residue. These parameters have been found to be important in various studies (7, 9, 12, 17) and are applicable to the system. Researchers (10, 37) have found that the temperature, the amount of NI-1+4-N, the amount of NO -3 -N, the moisture content, and the texture are among the important parameters associated with the nitrification pathway. They were chosen as likely nitrification variables for the restricted soil system. Other possible variables such as pH and soil areation probably are not significant in this system. The quality of the variable selections was tested before determining the final form of Subroutine TRNSFM. Variables tried in connection with the nitrate -N immo- needed to check the results of model routines and the final model. These also were obtained from the literature. Enough useful data were collected to allow the development of the initial equations. The data for the equations developed in this study were obtained from the literature as follows: Urea hydrolysis (8, 48) Mineralization- Immobilization (7) Nitrification data (10, 36) C: N ratio data (1, 6 ) The data used in this study to verify the output of the computer model were obtained from the literature as follows: Urea-N data (8, 48) Organic-N data (7 ) NH +4 data (7, 8, 10, 36) NO -3 -N data (7, 8, 10, 36). As noted later, some derivation data was included in the verification data set. Development of Equations: As previously mentioned most nitrogen transformations in soils take place too slowly to be approximated by equilibrium relationships. Therefore, a kinetic approach was selected to model the pathways. Each pathway was quantified by a preliminary rate equation developed using computerized multiple regression analyses of the data from the literature. The final basic equations appearing in the computer model were determined by modifying some of the preliminary constants to more closely approximate the data. The basic variables used in each regression analysis were those established from the literature review and the systems analysis. First, transformations such as logarithms, multiples, divisions, square roots, exponentials, and various combinations of these were performed on data for the basic variables. The transformed and basic data were then correlated with the rates to help determine which variable combinations gave the best linear relationships. The independent variables so chosen for each transformation pathway were included in a series of least squares multiple regression analyses. This provided equations for the planes of best fit through the data points. Usually many combinations of respective independent variables were tried before the best equation for a pathway could be found. Variables which contributed little to the goodness of fit were deleted from the final equation. The basic equation form was as follows: Y = C + b1X1 + b2X2 + b3X3 ... bX [51] where Y is the transformation rate (dependent variable). X is a basic transformed parameter (independent Page 11 variable) . b is a regression coefficient. C is a constant (Y intercept). Statistical parameters such as the F ratio, R2 value, and standard error of estimate of the dependent variable were used to help determine which combination of independent variables gave the best fit for each rate equation (19, 54). It was not necessary for the independent variables to be independent with respect to each other. Here, the basic idea was to find a model not to determine the interdependence of the independent variables. The regression equations were valid even though some of the independent variables were related. Urea Hydrolysis Rate Equation: The basic variables considered in the development of the urea equation were the temperature ( °C) and the urea -N concentration (ug/g soil) . The independent variables in the final equation were logro temperature ( °C) and loglo urea -N concentration. Other potential parameters were excluded for their low r values and /or lack of contribution to the fit. The rate units for this and all other rate equations used in the model were expressed in ug/g soil /day unless otherwise noted. The constant, coefficients, and statistical parameters for the urea equation appear in Table 4. The simple correlation coefficients (r) for each independent variable correlated with the rates provided some idea of which variables would contribute most to the fit of the regression plane. The respective r values were as follows; r(Var. 1)* = 0.622, r(Var. 2) = 0.678. The critical r value for 60 degrees of freedom is 0.250 at the 95 percent level of significance. However, a high correlation with the rate did not yield the expected contribution to the fit if the variable was highly correlated with one or more other independent variables. The F ratio of 624 caused rejection of the hypothesis that all the regression coefficients equaled zero. The critical F ratio for 59 degrees of freedom is 3.14 at the 95 percent level. * The R2 value of .723 indicated that 72.3 percent of the variance of the rate was accounted for by the regression. The s** for the rate showed that 68 percent of the points fell within -49.0 ug /g soil /day of the regression plane. This equation represented the best fit obtainable in a reasonable length of time using data from the literature (8, 48). Mineralization- Immobilization Rate Equation: A single equation was derived for the net rate of NI+4 -N immobilization or the net rate of organic -N mineralization depending on the sign. A negative rate indicates a loss of organic residue (mineralization) . A positive rate shows a gain of microbial cell material (immobilization). A similar sign convention is used throughout the model; a positive sign indicates a gain and a negative sign a loss with respect to that particular constituent. The basic parameters used in conjunction with development of the mineralization -immobilization equation are the temperature ( °C),the organic -N concentration (ug /g soil), the N11+4-N concentration (ug /g soil), and the C:N ratio of the organic residue. The final equation contains the temperature, the organic -N concentration and the loglo NH +4 -N concentration. The C:N ratio was excluded from this equation because a complete set of data was available for only one C:N ratio, 80. However, this important parameter was kept in the model by multiplying the output of the mineralization immobilization equation by the output of a linear equation involving the C:N ratio. For example, the multiplication factor equals unity at a C:N ratio of 80 and zero at a ratio of 23. The assumption is made that net immobilization occurs above 23 and net mineralization occurs below 23. The net rate at 23 is assumed to equal zero. The relationships for developing the equation were taken from the literature (l, 6). The final equation form is as follows: M = -2.51 + 1.85 x logro C:N ratio [52] where M is the multiplication factor. Since the C:N ratios of organic residues change as decomposition progresses, a method was developed to predict the C:N ratios with time. The literature showed that microorganisms release about 30 C atoms from organic residues for every N atom consumed (1, 12). The N may come from the organic residue or from NH +4 in the soil water or on the exchange complex. The C either is released as CO2 gas or used to produce microbial cell material. The N may be transformed to NH +4 or used in the production of cell material. The initial amount of C in the organic residue is estimated by multiplying the amount of residue by 0.4 (1, 12) . Likewise, the initial amount of N in the residue is approximated by multiplying the amount of residue by 0.4/C:N ratio (12) . If the ratio is greater than 23, the amount of residue carbon remaining after some time interval is approximated by subtracting 30 times the predicted amount of organic -N immobilized from the amount of residual C present at the start of the interval (1, 6, 12) . The amount of residue N is assumed to remain constant. That is, it is assumed that the microorganisms consume only the NH +4 mineral form of N in this C:N ratio range. The new C:N ratio is computed by dividing the amount of residue C by the amount of residue N. At C:N ratios less than or equal to 23, the residual amounts of C are computed in the same manner except that the amount of N mineralized is used as the computation base. The new amount of residue N is determined by subtracting the amount of N mineralized during the time interval. In this case the assumption is made that the microorganisms derive N only from the organic residues in this C:N ratio range. Again the ratio is recomputed by dividing the amount of residue C by the amount of residue N. When the amount of organic residue becomes equal to zero, the ratio is set equal to the average C:N ratio for the soil (e.g. in the range 5 -15). This allows for mineralization of dead microbial cells with time. A listing of the constant, coefficients, and statistical measure for the mineralization -immobilization equation is presented in Table 4. Independent variables other than those included in the final preliminary equation were rejected because their r values were too low or because they contributed very little to the regression sum of squares. In this case the critical R value is 0.40 for 43 degrees of freedom. The F ratio of 38.9 was well above the critical value of 2.83. The R2 value of 0.740 was quite good. A value above 0.5 was desirable but not essential in this study as Note: All remaining critical values refer to the 95% level. * *Standard error of estimate. * r(Var. 1) = r value for variable 1 in Table 4 (Urea Hydrolysis Equation). Page 18 TABLE 4. Variables, Constants, and Statistical Tests for the Urea Hydrolysis and Mineralization -Immobilization Rate Equations. UREA HYDROLYSIS EQUATION C + b1 logro (Temp) + b2 logro (Urea-N) Urea Hydrolysis Rate (ppm /day) = 4.13 102 b1=-1.56102 F ratio C -1.53 b2 R2 102 s = 6.24 = 7.23 = 4.90. 101 10 -1 10' MINERALIZATION-IMMOBILIZATION EQUATION Mineralization -Immobilization Rate (ppm /day) = C + b1 Temp. + b2 (Organic-N) = b1 = b2 = C b3 = will be seen later. The s for the rate indicates that 95 percent of the points fell within ±.490 ppm /day of the equation plane. The respective r values were as follows: r(Var. 1)* 2) = -0.769, r(Var. 3) = 0.706. Nitrification Rate Equation: The nitrification equation represents the net transformation of NH +4 -N to N0 -3 -N. This means that some NO -3 -N to NH +4 -N conversion is allowed in the model. However, the net result always is assumed to be the appearance of NO -3 -N. The basic variables used to develop the equation were the temperature (°C), the concentration of NH +4 -N (ug/g soil), the concentration of NO -3 -N (ug /g soil), and the soil moisture tension (bars). The independent variables included in the final preliminary equation are the temperature times the NH +4 -N concentration, the log10 NI+4 -N concentration and the log10 NO -3 -N concentration. Other basic variables and variable transformations were excluded because of their low r values or because they did not contribute significantly to the fit of the data points. Inclusion of the moisture variable in some form was attempted at some length, but the contribu- = -0.585, r(Var. tions to the R values were very small. The constant, coefficients and statistical parameters for the nitrification equation are presented in Table 5. The critical R value 160 degrees of freedom is 0.226. The F ratio of 29.1 is above the critical value of 2.67. The R2 of 0.384 is lower than was desirable for this equation. Also the s of 3.84 is high. The respective r values were as follows: * r(Var. 1) = 0.544, r(Var. 2) = -0.361, r(Var. 3) = 0.497. The fit was rather poor in that a good equation was needed for the transformation of N11+4 -N to NO -3 -N. The basic difficulty may have been a lack of good quality derivation data in the literature (10, 36) . However, this problem was offset when all the rate equations were combined as a unit (see page 62). NO- 3-N Immobilization Rate Equation: The NO- 3 -N immobilization equation quantifies the conversion of NO -3 -N to 8.92 2.16 2.70 3.92 + b3 log10 10-1 F ratio 10'3 R2 10 -2 s = = = (NH +4-N) 3.89 7.40 2.45 10' 10 -1 10 -1 10 -1 microbial cell material. As in the case of NH +4-N immobilization, the process is assumed to take place only at C:N ratios greater than 23. The equation does not allow direct NO -3 -N formation from organic -N, since this transformation pathway is highly unlikely. The constant, coefficients, and statistical parameters for the equation appear in Table 5. The basic variables used to develop the final equation were the temperature ( °C) /the organic -N concentration2 (ug /g soil), e (temperature ), and the (temperature x (organic -N concentration NO -3 -N concentration) ) /organic -N concentration. The respective values were as follows: r(Var. 1) = 0.418, r(Var. 2) -0.282, r(Var. 3) = 0.324. The F ratio of 9.96 is above the critical level of 2.83 for 43 degrees of freedom. The critical level for the r values is 0.401. The r, R2 and s values for the rate were within tolerable limits. - _ Method of Solving the Rate Equations: The basic rate equations were each derived independently and had to be solved as unit or system before any predicted output could be obtained. The method selected is particularly well suited to a high speed digital computer. The basic time interval is passed from Subroutine COMBINE. This means that the outputs from the rate equations initially are placed in terms of ug /g soil /At. A first approximation of the concentration of each nitrogen species at the end of a time interval is obtained in the following manner. 1. Each rate equation is solved independently based on the pertinent concentrations at the start of a basic time interval (e.g. 0.1 day) . 2. Appropriate additions to or subtractions from the initial concentrations are made based on the magnitudes and directions of the rates. Successive approximations for the concentrations are made by dividing the time interval passed from COMBINE (e.g. 0.1 day) into series of smaller and smaller time inter- *Here reference is being made to variables listed in Table 5. Page 19 TABLE 5. Variables, Constants, and Statistical Tests for the Nitrification and Nitrate -N Immobilization Rate Equations. NITRIFICATION EQUATION = Nitrification Rate (ppm /day) C + b1 Temp. (NI-1+4 = 4.64 = 1.62 b2 = 2.38 b3 = -2.51 - N) + b2 log10 (NH - N) + b3 log1° NO -3 - N) +4 C 10° F ratio bl 10-3 R2 10-1 s = 2.91 = 3.84 = 3.67 10' 10-1 10° 10° NITRATE -N IMMOBILIZATION EQUATION NO -3 -N Immobilization Rate (ppm /day) = C + bi Temp./(organic-N)2 + b2 exp (Temp.) + b3 (Temp. (organic-N) - (NO-3 - N) )/ (organic-N) = 0.00 bl = 1.52 b2 = 3.23 b3 = -4.90 F ratio C ( INPUT OP- AMMONIA -N SECTION UREA -N SECTION s 10-1 10-1 10-3 Construction and Operation: A generalized block diagram of Subroutine TRNSFM appears in Figure 13 (a complete Fortran listing is given in the Appendix) . The subroutine consists of six primary sections. Each contains several loops or routines related to the primary function of that section. The urea -N, organic -N - C:N ratio, NH +4 -N, and NO -3 -N sections are independent of each other so far as sequence is concerned. That is, the order in which they are arranged in the subroutine makes no difference in program operation. The sequence chosen is based on the order in which the sections were first studied. Of course the input and convergence-output sections have to appear at the beginning and end of the subroutine, respectively. The input section is concerned with establishing basic constants, and control and input data. Unit conversions are done to convert amounts in ug /segment to ug /g soil and moisture tensions in cm of H2O to bars. The urea -N section includes routines for the initial time interval length and the initial concentration of urea -N. Also, the urea hydrolysis rate equation, an expression to compute the amount of urea -N present at the start of the next time interval, special logarithmic rate functions at limiting tem- ORGANIC -N C:N RATIO SECTION COMPUTE NITROGEN CHANGES CRETURN TO COMBINE R2 10-15 10° val lengths until the results of one series agree with the previous series within CONVERG 1 * ug /g soil. That is, the system converges. The output from one time increment becomes the input for the next. Usually, division of an interval into 2 to 64 intervals is sufficient to attain the desired convergence depending on the magnitude of change during the interval. The method amounts to a simultaneous integration of all the rate equations to generate predicted nitrogen concentrations. The changes in concentration returned to subroutine COMBINE are computed by subtracting initial from final concentrations for the time interval required. ENTER SECTION 10° = 9.96 = 4.21 = 4.11 J Figure 13. Generalized block diagram of Subroutine TRANS * Page 20 See User's Manual peratures and urea -N concentrations, and other control loops are included in this subroutine section. The computer passes completely through this section before proceeding to the next. The organic-N - C:N ratio section is the most involved part of the program in that it contains the largest number of expressions and loops. The initial parts are concerned with the concentrations of organic -N, NH +4 -N, and NO"3-N present at the start of a time interval. These data are necessary for the first set of calculations pertaining to an interval. After this, the data for the remaining smaller time increments are generated entirely by the subroutine. After establishing the initial C:N ratio and setting some of the constants according to the C:N ratio range, the program enters the mineralization -immobilization rate equation. The resulting rate is modified according to the C:N ratio and the limiting temperatures, moistures, and concentrations. Also, certain other control loops are employed at this point. Next is the NO -3 -N immobilization rate equation. It is used at this point so that its results can be used along with the output from the mineralization -immobilization equation to calculate the C:N ratio at the start of the next time interval. Loops concerned with the limiting temperatures, moistures, and concentrations follow the equation. The usual control loops are included at this stage. The C:N ratio is recalculated in the routine which follows. Separate loops are used for the C:N ratio ranges greater than 23 and less than or equal to 23. The basic method of recalculation has already been described. The last part of the organic -N - C:N ratio section is concerned with storing the amounts of residue carbon and nitrogen present at the end of a call and computing the amount of organic -N present at the start of the next time increment. The NI+4 -N section of the program contains the nitrification rate equation along with the appropriate limiting rate functions and control loops. Again, the last part is concerned with the computation of the amount of NH +4 -N present at t + 1, where t is time. The NO -3 -N section is rather short since the appropriate rates have already been calculated. The routine cornputes the amount of NO -3 -N present at t + 1 based on the initial amount of NO -3 -N and the output from the nitrification and NO -3 -N immobilization equations. If the end of a time step passed from COMBINE has not been reached, control is shifted back to the urea -N section for the next time increment. Otherwise control is passed to the next section. The final section of the subroutine consists of the convergence and output routines. The convergence routine compares the output from one series of time increments with the output from the previous one. If the two differ by not more than CONVERG1 ug /g soil, control is passed to the output area. Otherwise, the number of time intervals is doubled, the concentrations of the nitrogen species stored, and control passed to the urea-N routine for another series of approximations. The output area computes delta values for changes (ug /At) in urea -N, NH +4 -N, organic-N, and NO -3 -N. These changes are then returned to Subroutine COMBINE. Coefficient Adjustments: After the subroutine was constructed, its predicted output was compared with observed data. The predicted curves had the proper shape, but some were displaced to some extent from the observed situation. This could have been caused by the effects of linearizing a non -linear system during the regression analysis or by bias introduced into the derivation data by experimental errors. However, it indicated that the choice of variables or terms was approximately correct, but that some coefficients were slightly in error. These discrepancies were corrected by changing certain coefficients to more closely fit the observed curves in general. That is, no attempt was made to fit each individual soil or run with a separate set of coefficients. The changes made applied to the entire set of data. A summary of the coefficient adjustments appears in Table 6. Also at this stage the limiting rate functions or expressions were added to the program to account for changes near limiting values of temperature, moisture and concentration. These were developed by curve fitting with respect to the observed data. They were necessary because the regular rate equations tended to "break down" near these boundaries. A low temperature correction for each rate was found to be necessary below about 10 °C. Here the original rates were multiplied by the output from a logarithmic function based on the temperature. The rates became equal to zero at about 4 °C. No upper limits or corrections were necessary for high temperatures because the equations appeared valid at most maximum soil temperatures occurring below the surface. The moisture correction for tensions below about 10 bars was handled in a manner similar to the temperature correction. However, the rates were still above zero at 15 bars, the lowest moisture content allowed in the subroutine. The equations were valid at the upper moisture limit of field capacity. The corrections applied only to the mineralization immobilization, nitrification, and NO -3 -N immobilization equations. There was no evidence to suggest a moisture correction for the urea hydrolysis equation in the range considered in the study. The low concentration levels were handled in a slightly different manner. If a rate equation predicted that a greater amount of nitrogen would be transformed than was present at that time (based on rate units of ug/g soil /At), the rate was set equal to the amount remaining. Then the division was made by the number of time increments /basic time interval. This procedure generated a "tailing off" effect near low concentration levels. The procedure seemed to work well because the curves kept their observed shapes near TABLE 6. Summary of Adjustments Made in Regression Coefficients. Equation Urea Hydrolysis Mineralization Immobili zation Nitrification Nitrate -N Immobilization *NC Page 21 C:N Ratio 1 b2 NC* NC b3 < 23 NC NC 1.60.10° > 23 NC NC 7.83.10-1 < < < 23 23 23 > 23 = No Change NC NC 4.50.10° 8.00.10-4 2.38.10-4 -2.10.10° NC NC NC NC NC NC concentration boundaries and eventually went to zero due to rounding errors. Generally, the effect was generated at levels below about 5 ug /g soil. The urea hydrolysis equation was a slight exception to the above procedure. Here the rate was set equal to the amount remaining at rates less than 5 ug /g soil /day. This was necessary because of the very rapid hydrolysis rate with respect to one day. The regular equations have good results at concentrations near the maximums expected with normal field applications of nitrogen fertilizers. 4001 120- - 100 - 80- OBSERVED PREDICTED 6040- Verification: 20- Typical observed* and predicted curves for urea -N, organic -N, NH +4 -N, and NO -N concentrations versus time are presented in Figures 14, 15, 16 and 17, respectively. These and similar plots were used to verify Subroutine TRNSFM for several alkaline soils incubated under a range of conditions allowed in the model. Sets of observed and sets of predicted values for each nitrogen species studied were compared by using a least squares linear regression analysis to obtain the sample correlation coefficient (r), the linear regression coefficient (b), the Y-intercept (Yo), and the s * *. Here the observed and predicted concentrations served as the independent and dependent variables respectively. A perfect fit for the predicted values would yield an r value of 1.0, a b value of 1.0, a Yo of 0.0, and an s of 0.0. o 10 20 TIME 30 40 50 (DAYS) Figure 14. Observed and predicted urea -N with time. 140- -- 120- OBSERVED PREDICTED 100-, 80- Urea Nitrogen. A total of 31 pairs of observed and predicted data points yielded the following regression equation 60- Y 40- I IO I I 20 TIME 30 (DAYS) 40 50 140 - 100 80 OBSERVED PREDICTED 60 40 20 0 10 20 30 + 0.925X, [53] The numbers 17.1 and 0.925 refer to the Y-intercept and the regression coefficient respectively. The r value equaled 0.992 while the s was equal to 17.1. All units were expressed in ug urea -N /g soil. The maximum urea -N concentration in this set of verification data was 400 ppm. This concentration was close to the upper limit for urea -N allowed in the subroutine. The values for Yo and b indicated the overall predicted urea -N output was slightly higher than the overall observed concentrations for the examples used to derive the previous equation. One possible explanation for this difference would be an incomplete recovery of urea -N in the laboratory. The computer model more closely approximated the observed values for NI+4 -N and NO -3 -N in the same samples. The r value showed that 98.4 percent of the Y variance was accounted for by the regression of Y on X. The s of 17.1 meant that 95 percent of the predicted values fell within ±34.2 ppm of the regression line. Figure 15. Observed and predicted organic-N with time. 120 17.1 where X was an observed urea -N concentration, Y was a urea -N concentration yielded by this equation (not by the subroutine) . 20o = 40 Organic Nitrogen: The following equation was obtained using 56 pairs of observed and predicted data points: 50 TIME (DAYS) Y Figure 16. Observed and predicted NH4 -N with time. *Approximately 50% of this data was new data not used in the rate equation derivations. **Standard error of estimate for the predicted values. = 11.0 + 0.768X [54] Here the observed and predicted values were expressed in terms of ug organic -N /gm soil. The equation represented a line which was located above the theoretical line (Yo 0.0, b = 1.0) for organic -N concentrations below about 55 ppm, the point where the lines crossed. The organic -N data from the literature which were used for purposes of verification fell in a range from about 15 to 60 ppm. The Page 22 The r value of 0.972 indicated that 94.5 percent of the variance in the predicted NO -3 -N concentrations was accounted for by the regressions. The s of 7.90 showed that 95 percent of the predicted NO -3 -N concentrations compared in this analyses fell within ± 15.8 ppm of the regression line. 140 120 - OBSERVED PREDICTED 10080 - SUBROUTINE FL 60- The mixing cell has numerous references in the literature (42) as a means for simulating dispersion of soluble chemical species. Subroutine FL uses mixing cells for each soil 4020- o i i I i IO 20 30 40 TIME ( DAYS 50 ) Figure 17. Observed and predicted NO3 -N with time. clustering of points within this range could partially account for the b value of 0.768 as well as the r value of 0.774. A wider range of organic -N values probably would improve both the b and r values. The s of 6.55 showed that 95 percent of the predicted points fell within ± 13.1 ppm of the regression line. Ammonium Nitrogen: A total of 83 pairs of observed and predicted data points was used to derive the following regression equation Y = 11.7 + 1.05X [55] The simple correlation coefficient (r) was 0.969, and the s was 9.47. The concentrations were expressed in ug NH +4 -N/g soil. Here the regression line was slightly above and parallel to a theoretical line with a slope of 1.0 and a Y-intercept of 0.0. A possible explanation could be incomplete recovery of NI+4 -N in the chemical analyses, since the model appeared to more closely predict the concentrations of those nitrogen species for which the more reliable analytical methods were available. The r value indicated that 93.8 percent of the variance in the predicted values was accounted for by the regression. The s showed that 95 percent of the predicted concentrations fell within -!-18.9 ppm of the regression line. For this case of NH +4 -N, the maximum concentration considered in this set of verification data was 150 ppm while the minimum was 0.0 ppm. Nitrate Nitrogen: The following regression equation was derived using 86 pairs of observed and predicted data points: Y = 5.98 + 0.884X [56] The r value was 0.972, and the s for the predicted concentration was 7.90. The units were in terms of ug NO- 3 -N /gm soil. The regression line crossed the Y -axis at 5.98 and had a slope of 0.884. This meant that the regression line fell slightly above the theoretical line at concentrations below about 50 ppm and slightly below the line above this concentration. The maximum NO -3 -N concentration in this set of verification data was about 150 ppm, and the minimum about 2 ppm. segment. Moisture flow data is used to compute mass inputs, outputs, and storage changes for each cell. Since the water table is assumed to have a fixed location, the assumption is made that solute concentrations in the ground water immediately adjacent to the last (lowermost) segment (mixing cell) are the same as those in the last segment at the end of the previous time step. This assumption is necessary because upward as well as downward movement of water is being modeled. Surface inputs to the system are simulated as follows. First the assumption is made that surface fertilizer additions mix completely with water applied to the soil. Then the amount of water infiltrating together with its solute concentrations is treated as an input to the first segment. In no case may the volume of water entering a segment over a time step exceed the segment pore volume or exceed the volume of water contained in a segment from which flow is taking place. If this situation occurs, the time steps must be reduced or the segment increased. Otherwise mass balance may not be maintained with respect to the system. Another basic assumption made in Subroutine FL is that only soluble chemical species are capable of being moved with the water. Here the various soluble species are all treated as having the same mobility. However, the concentrations of the soluble species in a segment will change from one time step to another as a function of the various chemical and physical processes involved. Theory of Subroutine FL: The Moisture Flow Program* provides Subroutine FL with the volume of water contained in each soil segment at the end of each time step. In addition, it supplies values for the volumes of water entering and leaving each segment during each time step. A positive sign indicates downward flow while a negative sign designates flow upward. FL estimates the mass of each soluble species moving into and from each segment over a time step in the following manner. The assumption is made that each soluble species moves freely with the water contained in the segment of interest. Since upward flow is included, some segments may receive component masses from two adjacent segments over a time step. The mass contributions from adjacent segments for a time step are computed by multiplying solute concentrations (assumed constant for any one segment) by the appropriate flow volumes. Mass losses from a particular segment are computed in a similar manner using concentrations and flow volumes from the segment. Since soluble component mass inputs and outputs are known for each segment, the net changes in mass can be computed from *Following data conversion of the interfacing program (INTFACE). Page 23 mass balance considerations. With the assumption of complete mixing, new concentrations may be computed for consideration over the next consecutive time interval by dividing soluble component masses by the volumes contained in the respective segments. The same set of solute concentrations is used for any one time step. SUBROUTINE UPTAKE NO -3 and NH +4 are primary forms of nitrogen taken up by plants (38, 39 ) Nitrogen uptake has been shown to be directly proportional to root density, (i.e. root mass per unit volume of soil) The subroutine uses data for total plant uptake of nitrogen, root distribution with depth, and uptake distribution between NO -3 -N and NH +4 -N to compute NO -3 -N and NH +4 -N uptake for each soil segment and each time interval. The assumption is made that the plant root distribution is independent of time. Data for total plant uptake of nitrogen with time either may be read into the program or computed by Subroutine UPTAKE. The latter method is based on the assumption that N uptake is proportional to consumptive use. In this case, the user must supply the proportionality constant. Consumptive use data is supplied by the Moisture Flow Program. Values for NO -3 -N and NH +4 -N uptake from each segment are computed by one of the two following methods. (1) Total N uptake is multiplied by the fraction of roots in the segment and the fraction of uptake as NO -3 -N or NH +4-N, respectively if plant uptake data is read in, or (2) consumptive use for each segment is multiplied by the respective NH +4 -N or NO -3 -N concentrations and combined proportionality constants if the consumptive use method is selected. . . MISCELLANEOUS SUBROUTINES Subroutine PRNT: This subroutine prints control and /or input data. Print options are provided to allow printing control by the user. Subroutine MCHECK: This subroutine computes the nitrogen mass balance status (i.e. inputs -outputs vs. delta storage) of the system. The subroutine may be called at various intervals during program execution. Any discrepancies in mass balance indicate that time intervals which are too large are being used or that moisture flow exceeds pore volume or current pore content. A detailed mass balance report is printed after each call. Subroutine TEMP: TEMP reads weekly soil temperature data for the temperature horizons and assigns these data to the proper soil segments. Subroutine CHK: This subroutine examines mass changes due to nitrogen transformations, and ion exchange and solution chemistry to determine if Subroutines TRNSFM and XCHANGE, respectively should be called for the particular soil segment and time interval. The criteria for making these decisions are read into the program as constants. Subroutine OUTPUT: This subroutine writes on Tape 2 predicted values of the delta and cumulative amounts leached for the components listed below. The user supplies the write interval in days. Delta amounts correspond to the write interval. 1. Volume of water* 2. NO -3 -N 6. Na+ 7. Mg" 3. NH +4-N 4. Urea -N 5. Ca" 8. HCO-3 9. Cl10. CO-3 *Units in cc All remaining units in µg. Subroutine UNITSI: This subroutine converts units from meq /1 to ug /soil segment and from ug/soil segment to meq/1. Organic matter units are converted from ug /gm soil to ug /soil segment and vice versa. Subroutine THEDATE.: This subroutine and Subroutine DAY compute the date from the day number of the run. The date is expressed as an integer number (e.g. March 21 would be expressed as a 21) . Subroutine IDA Y: This subroutine together with Subroutine DAY computes the day number of the run from the calendar date, the reference month, and the reference day. VALIDATION OF THE BIOLOGICAL-CHEMICAL PROGRAM In anticipation of the development of the model presented here, a field lysimeter study was established at Fresno, California. Details of the experimental procedures have been discussed elsewhere (58). Two sets of lysimeters were chosen to verify the program discussed in this section. They were lysimeters 2 and 3 which contained a Panoche clay loam soil, and lysimeters 5 and 6 which contained Panoche fine sandy loam. The first set was fertilized with NH4SO4 and the second set with KNO3. Soil moisture contents in the lysimeters varied from those which were predicted to occur under field conditions, and techniques of estimating crop consumptive use were found to be inadequate to predict plant root withdrawal of soil moisture in these lysimeters. To predict moisture contents and moisture fluxes in the lysimeters so that these properties could serve as inputs to verify the Biological Chemical Program, a simplified moisture predicting program was developed. This program, which has been discussed elsewhere (26), was capable of satisfactorily matching soil moisture tensions throughout the growing season. The mechanisms used to match these experimentally measured tensions included adjusting effective root distribution, adjusting Blaney-Criddle crop consumptive use constants, and adjusting the tension of an imaginary node above the soil surface to approximate evaporation. Predicted and observed soil moisture tensions for lysimeter 2 are shown at two depths in Figure 18 under a growing barley crop. Observed and predicted values for uptake of nitrogen by the barley and milo appear in Table 7. The predicted values for barley are slightly high, while those for milo are low. The uptake constant of 4 for barley (see Subroutine UPTAKE) yields reasonable estimates of plant uptake of N. However, the much higher uptake constant of 40 for milo still gives a significant underestimate. The low amounts of NO -3 present in the soil water system could account for this discrepancy. Probably, the milo is also using NH% as a source of N. It would appear from the data presented here that Subroutine UPTAKE yields at best, crude approximations by application of consumptive use and uptake constants. Since the nitrogen removal by plants is the most important mechanism of nitrogen removal from irrigated soils, further work should be initiated to develop a better subroutine. Until this is done, it is recommended that data on nitrogen uptake Page 24 TABLE 7. Nitrogen Uptake (g) by Barley and Milo. Soil Type Panoche CL Panoche FSL Panoche CL Fertilizer Crops Lys Straw Grain Roots (NH4)2SO4 Barley 2 .35 .34 .43 .38 .28 .38 .94 1.00 1.14 1.12 .77 .67 .53 .53 .65 .57 .42 .57 3 KNO: (NH4)2SO4 Barley 5 Milo 6 2 3 by plants be read into Subroutine UPTAKE as inputs. Substantial uptake data are available in the literature (28, 38). Near the end of 1969, lysimeter 3 was dismantled and soil samples from several depths analyzed for organic -N. The results of this analysis together with predicted values from the model appear in Tables 8. According to the model an increase in organic -N occurred near the surface. The TABLE 8. Predicted and observed final organic -N distribution in lysimeter 3 after one year. Depth (cm) 0- 15 15- 30 30- 45 45- 60 60- 75 75 -105 105 -120 120-135 135 -150 150 -165 165 -180 Observed Organic -N (ppm) Predicted Organic -N (ppm) 358.0 310.0 288.0 353.0 281.0 176.0 178.0 127.0 134.6 124.0 148.0 332.5 334.3 330.4 328.7 324.0 144.5 144.3 144.2 144.6 147.4 147.6 Total Observed Total Predicted 1.82 1.87 2.20 2.20 2.24 2.24 .86 .86 2.22 2.07 1.47 1.62 same phenomenon was observed in lysimeter 3. Data pairing of predicted and observed organic-N concentrations with depth yielded a correlation coefficient of 0.954. The slope of the regression line was 0.986, while the Standard Error of Estimate was 27.6 ppm. The predicted and observed total nitrogen concentrations in the leachates, as a function of time, were similar for each of the various lysimeters. For brevity only the results for one of the lysimeters will be given here. A plot of the predicted and observed total nitrogen in the leachate with time is shown in Figure 19 for lysimeter number 2. The scatter exhibited by the observed data points may be due to sampling errors or errors in the chemical analysis. Note that the predicted curves pass through the observed scatter of points. The conclusion may be made that the predictions are within the experimental error of the measured values. No attempt was made to verify the salt content predicted by the model. However other work (24, 25) has shown that the approach used here should yield reasonable results. It should be pointed out that there are astronomical possible combinations of factors which could change the nitrate content, and the results verified, only represent a small finite number. Thus one can only conclude that to date the program seems to do an adequate job for the purpose intended. This does not mean that future verification will not show inadequacies in the Biological-Chemical Program that are not recognized at this writing. Page 25 180 180- 160 160- 140 140- 120 20- 100-I 100 -- >- a a 80- 80 DEPTH 60 - = DEPTH 37cm. 60- Observed - Predicted 40 40- 20 20- = 73 cm. Observed Predicted i t 0 0 f 1 +50 0 -200 -400 -600 1 -800 +50 0 TENSION (CM OF WATER) 1 1 Figure 18. Observed and predicted soil moisture tension for lysimeter 2 at 37 and 73 cm. depth. Page 26 1 -200 -400 -600 TENSION (CM OF WATER) 604428e.., I2 .. a 0 ' 1 20 10 40 30 ' I 50 i 60 70 80 90 100 110 60- á 44z 28. 1 J . 0 120 130 140 150 160 170 240 250 260 270 280 290 180 190 , 260 210 220 230 60442812- 0 300 310 320 330 340 DAYS Figure 19. Observed and predicted NO3 -N concentration in efftuent from lysimeter 2. Application To An Environmental Problem Currently there is concern on the effect of irrigated agriculture on the quality of percolating water (39, 58, 60) Questions such as how N fertilizers affect the N content of effluent leaving agriculture are being asked. It is clear that many soil and climatic factors and management practices would affect the above. Since the model presented here was designed to account for the various factors and practices, and since it is possible in the model to single out and change one or more conditions while holding others constant, one may assess, for example, the effect of different fertilizer practices. To demonstrate the usefulness of theoretical calculations, it was decided to consider the case where three different levels of nitrogen fertilizers were used under identical climate and soil factors, and under the same management practices. . INPUT ASSUMPTIONS The soil parameters and climatic data listed above were field data collected by the U.S. Bureau of Reclamation. It was assumed that the soil in an area of interest is a Panoche loam and that its properties were those given in Tables 9 and 10. Further, it is assumed that the mois- ture application data and other management practices are repeated annually, Table 11 thru 14. The plant uptake and consumptive use data was also collected by the Bureau of Reclamation and was considered to be representative of the area. The 108 lb N acre ( "Normal ") fertilizer application (Table 12) and other management practices were felt to be typical of those currently in use in the San Joaquin Valley of California. The imposed moisture and nitrogen removal pattern by the crop are assumed to be those given in Tables 15 and 16. The temperature at several depths is given in Table 17. RESULTS AND DISCUSSION As mentioned in the previous section, all of the above mentioned annual data were assumed to repeat annually for the calculations when used with the Biological-Chemical Program. It should be pointed out that this assumption was not required to perform calculations, but was used to reduce computer time. The calculations were made over varying increments of time to allow examination of the generated values. The total time required by a Control Data 6400 computer including restart time was 32/3 hours. Page 27 TABLE 9. Initial Soil Analysis. Chemistry Horizon No. Exch. Cap. Gypsum (meq/ 100 gm soil) Depth (cm) 0- 30 30- 61 61- 92 92 -122 122 -152 1 2 3 4 5 27.4 29.5 30.0 31.2 88.8 32.5 34.8 35.3 35.4 39.0 C:N Bulk Density Org. Mat. (ug /gm soil) Ratio of O.M. CAL (lime) 1.3 1.3 1.3 1.3 1.3 2135 1585 1278 1175 1132 5.0 5.0 5.0 5.0 5.0 1.0 1.0 1.0 1.0 1.0 TABLE 10. Initial Soil Analysis of 1:1 Soil Extract. (meq/l) Chemistry Horizon No. Depth (cm) 0- 30 31- 61 61- 92 I 2 3 92-122 122-152 4 5 *NH +4 NO-3 Urea Ca ++ Na+ Mg++ HCO-3 0.029 0.015 0.011 0.012 0.013 0.60 0.00 0.00 0.00 0.00 0.00 11.9 10.0 12.5 18.3 31.7 53.4 76.5 84.8 103.7 2.2 2.3 1.5 2.0 2.2 3.8 1.8 1.7 5.5 1.1 1.06 1.52 1.58 4.16 24.2 Cl CO -3 SO =4 0.1 0.1 37.1 6.3 10.2 18.3 52.6 71.1 75.0 89.4 0.0 0.0 0.0 30.2 42.9 *Estimated from total NH +4 TABLE 12. Fertilizer Applications. TABLE 11. Moisture Application Data. Application No. 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 Date Month Day (cm) (in) 01 01 01 06 02 02 02 03 03 03 04 05 06 07 07 08 09 06 0.61 0.30 0.91 0.91 3.35 0.61 0.61 7.62 0.30 4.88 8.84 12.80 7.92 7.92 11.58 6.1 5.18 0.30 0.61 0.91 0.61 0.61 84.09 0.24 0.12 0.36 0.36 10 19 11 11 20 21 22 12 12 12 Day No. Amount 15 21 15 21 06 15 21 15 15 15 01 15 10 15 15 06 21 01 06 21 Total Amount applied (lbs N /acre) Type Half Type* R I R R 1.32 I 0.24 0.24 3.00 0.12 R R 1.92 3.48 5.0 3.12 3.12 4.56 2.64 2.04 0.12 0.24 0.36 0.24 0.24 33.12 I 74 UREA 105 135 166 196 NH4 NH4 NH4 NH4 NH4 NH4 222 258 6.79 2.14 8.24 5.95 8.24 4.13 4.90 40.4 I Double Normal 13.6 27.2 8.56 33.0 23.8 33.0 4.28 16.5 11.9 16.5 16.5 19.6 8.26 9.80 80.8 162.0 R I I TABLE 13. Organic -N Applications. I I I I Day No. C:N Ratio I R R 227 30 Amount Applied (lbs N /acre) Half Normal Double 26.7 26.7 26.7 I R R TABLE 14. irrigation Water Analysis (ppm). *R denotes rainfall or precipitation as the water source, while I denotes irrigation. NH+4 NO-3 Ca++ Page 28 0.05 Na+ Mg++ HCO-3 0.10 19.4 37.4 10.5 79.9 Cl- CO-3 SO-4 48.6 0.60 36.5 TABLE 15. Evapotranspiration Data. Period No. 1 2 Month Dates 01 01 16 -31 02 02 03 03 04 04 05 05 06 06 07 07 08 08 09 09 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 10 10 20 21 11 11 22 23 24 12 12 1 1 Evapotranspiration (cm) (in) 0.20 0.20 0.28 0.28 0.81 0.81 -15 -14 15 -28 1 -15 16 -31 1 -15 1.78 1.78 16 -30 -15 16 -31 1 -15 16 -30 1 -15 16 -31 1 -15 16 -31 1 -15 16 -30 1 -15 16 -31 1 -15 16 -30 1 -15 16 -31 4.06 4.09 5.89 6.17 1 Total* TABLE 17. Weekly Temperature Data. 8.89 9.40 6.86 5.08 2.79 2.54 0.02 0.02 0.08 0.08 0.10 0.10 62.31 Temperature Horizon Depths (cm) 0 -20 0.08 0.08 0.11 0.11 0.32 0.32 0.70 0.70 Week No. 1 2 3 4 5 6 7 1.60 1.61 8 2.32 2.43 3.50 3.70 2.70 2.00 9 10 11 12 13 14 15 1.10 1.00 0.01 16 0.0I 17 18 19 0.03 0.03 0.04 0.04 24.54 *Total amount of the inclusive dates shown under period column. TABLE 16. Plant Uptake of Nitrogen. Month Jan. Feb. March April May June July August Sept. Oct. Nov. Dec. Uptake (lbs N /acre) 0.30 0.30 0.45 0.45 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 1.30 1.30 35 36 37 38 39 2,80 2.80 6.40 6.40 9,20 9.60 14.0 14.6 10.0 8.6 4.3 4.0 0.10 0.00 0.10 0.10 0.20 0.10 40 41 42 43 44 45 46 47 48 49 50 51 52 53 Page 29 20 -46 46 -152 Temperatures ( °C) 8.9 8.9 8.9 8.9 10.0 10.0 10.0 10.0 12.2 12.2 12.2 12.2 12.2 15.6 15.6 15.6 15.6 18.9 18.9 18.9 18.9 10.0 10.0 10.0 10.0 11.1 11.1 11.1 11.1 12.8 12.8 12.8 12.8 12.8 16.1 16.1 16.1 16.1 18.9 18.9 18.9 18.9 22.2 22.2 22.2 22.2 22.2 24.4 24.4 24.4 24.4 23.3 23.3 23.3 23.3 23.3 21.1 21.1 21.1 21.1 20.6 20.6 20.6 20.6 20.6 22.8 22.8 22.8 22.8 22.2 22.2 22.2 22.2 22.2 21.1 21.1 21.1 16.7 16.7 16.7 16.7 12.2 12.2 12.2 12.2 12.2 10.0 10.0 10.0 10.0 10.0 21.1 17.8 17.8 17.8 17.8 14.4 14.4 14.4 14.4 14.4 11.7 11.7 11.7 11.7 11.7 16.7 16.7 16.7 16.7 15.6 15.6 15.6 15.6 16.7 16.7 16.7 16.7 16.7 17.8 17.8 17.8 17.8 18.9 18.9 18.9 18.9 20.1 20.1 20.1 20.1 20.1 21.7 21.7 21.7 21.7 22.2 22.2 22.2 22.2 22.2 21.1 21.1 21.1 21.1 20.1 20.1 20.1 20.1 18.9 18.9 18.9 18.9 18.9 17.8 17.8 17.8 17.8 17.8 2.75 Water Movement: Theoretical values as calculated by Program MOISTRE for moisture flow to and from the water table over a one year period are shown in Figure 20. In addition the theoretical moisture content at each node and the moisture movement between nodes were calculated and stored on tape for use with the BiologicalChemical Program. The above data were too voluminous to present here. Nitrogen in effluent: The predicted nitrogen concentrations in water moving into the water table for the three levels of fertilization are shown in Figure 21. The initial and final organic matter contents through the profiles are given in Table 18. It will be noted that during the first year, the fertilizer application level had little effect on the effluent. This is 2.50 - 2.252.00- - 1.75 1.501.25 - 1.00- 0.750.50 - 0.250.00 -0.250.50 JAN 1 3 4 5 6 7 8 9 10 427 427 317 317 256 256 235 235 226 226 99.7 16.4 15.6 278 42.1 41.8 14.1 12.1 168 196 11.0 12.3 13.3 22.3 103 201 193 213 214 207 175 264 227 226 205 206 197 196 4 I MAY I JUN 152 121 ( JUL 182 I AUG ISEPT OCT NOV I DEC 213 244 274 305 335 365 ( HALF i I 3 APR NORMAL DOUBLE i i -f I 2 I 91 undoubtedly due to the fact that the added fertilizers were negligible in comparison to the soluble N species present in the soil. At the 189 lb N /acre /year fertilizer rate it will be noted that a stimulation of N release occurred and reached a maximum during the 5th year. It is apparent that the high rate of fertilizer application increased nitrate in the effluent over the other two application rates. This higher nitrate movement would be in line with some observations. It should be stressed though, that luxury consumption by the crop was not taken into account. Thus one would expect - I MAR Figure 20. Predicted daily leachate with time. Positive leachate indicates drainage, negative leachate indicates upward flux across lower boundary. 55.9 52.3 -. I 60 TIME (MONTHS AND DAYS) Half Fertilizer Normal Fertilizer Double Fertilizer Soil Application Application Application Segment Initial (67 lb N /acre) (108 lb N /acre) (189 lb N /acre) 2 FEB I 32 TABLE 18. Organic -N Distribution in Profile (ppm, after 13 years). 5 - I 6 7 1 1 1 8 9 IO 1 II 1 12 YEAR Figure 21. Predicted effect on NO,-N concentration in effluent by increasing fertilizer rates. Page 30 1 13 a somewhat lower value in an actual situation. The 108 lb /acre and 67 lb /acre rates were of considerable interest. As can be seen in Table 19 the 67 lb /acre rate was not sufficient to provide the N necessary for crop production and would represent a nitrogen deficient case. Nevertheless, it will be noted that the curves cross each other at several points. This indicates that a fertilizer application timed so as to provide adequate, but not excessive N does not contribute to N pollution. It should also be noted that during the later years at the two higher levels of fertility a cyclic but different pattern exists. At the highest fertilizer rate a maximum occurs at the first of the year, and a minimum in mid -season, whereas, at the 108 lb N /acre a maximum occurs in mid-summer. It will be noted at the low rate that starting with year 12 several maximums and minimums occur. Each maximum follows a fertilizer application. It appears that the higher rate, 108 lb N /acre, is in some way buffered. Although one cannot directly compare the results calculated here with analysis of drain effluents, such comparisons are of interest. In the areas where the 'soil samples were taken that were used for the calculations, a study of drain effluents has been conducted (13) . It was found that the N in drains was cyclic, as predicted, and that the concentrations were within the range calculated here. Thus it is felt that the work reported here is in agreement with field observations. User's Manual For Model MOISTURE FLOW PROGRAM INTRODUCTION: The purpose of this manual is to provide the user with detailed operating instructions for the Moisture Flow Program. Program input, program output, interfacing with the Biological -Chemical Program, and re -start capabilities of the program are discussed in this user's manual. The theory of Program MOISTRE and its subroutines was discussed - TABLE 19. Plant-N Uptake (for half fertilizer application 67 lb N /acre). Year 1095 1095 1095 1095 1095 1095 1095 1095 1095 1095 1095 1095 1095 1 2 3 4 5 6 7 8 9 10 11 12 13 : 906 935 850 861 849 856 763 783 721 - K(6) - 4.67 x 10 -5 e35.80 the appropriate Fortran IV statement function could be written CONDUCT(Z) PROGRAM INPUT: Input to the Moisture Flow Program is of two types (A) Input to the source deck of Program MOISTRE, and (B) data card input to the Moisture Flow Program. 1095 1095 1095 1039 INPUT TO PROGRAM MOISTRE SOURCE DECK It is not convenient for the equations relating hydraulic conductivity (K) to moisture content, and soil moisture diffusivity (D) to moisture content to be supplied from data cards because the forms of these equations may vary from one soil to another. Further, the form of the diffusivity moisture content relationship may change within a given soil for the range of moisture contents considered. Equations expressing soil moisture diffusivity and unsaturated hydraulic conductivity as functions of soil moisture content are inserted as "statement functions" (16) at the beginnning of Program MOISTRE. For example, if the unsaturated hydraulic conductivity (K ) is related to the moisture constant (B) according to the expression previously. PROGRAM LANGUAGE AND COMPUTER TIME The source program is written in Fortran IV for Control Data Corporation 6000 series machines (16). Compilation has been accomplished on the C.D.C. 6400 digital computer at the University of Arizona using both the RUN and FTN compiler options. Although the amount of machine storage required and time needed to compile and execute is highly dependent on the computer system, on the C.D.C. 6400 the Moisture Flow Program will compile in a field length of 60,0008 words (including compiler program) under FTN in about 9 seconds. Compiler output is loaded in approximately 55,0008 words and is executed much more efficiently when compiled under FTN than under RUN. A 30 node problem requires approximately three seconds of computer time to simulate each day under FTN, although this time will vary as the number of time intervals per day changes. Actual (all units Ug /cm2 /yr) Imposed = 4.67* 10.** (-5.) *EXP(35.8*Z) where Z corresponds to the moisture content. If multiple relationships are needed to describe these properties over the desired moisture range, multiple statement functions must be used. The diffusivity and conductivity relationships are referenced at three points in Program MOISTRE. Each of these points is indicated by comment cards in the source deck. If multiple relationships are used, the appropriate diffusivity or conductivity statement function must be referenced at each of the three points. DATA CARD INPUT TO MOISTURE FLOW PROGRAM Data card input to the Moisture Flow Program consists of the 7 card groups shown in Figure 22. All seven card groups must be present in a given run, however, the number of data cards composing some card groups can vary as indicated in Table 20. A description of the variables and input format for the cards in data card groups 1 -7 is shown in Tables 21 -27. In the following description if the indicated data-name is Page 31 /Group #7 Group #6 Tabulated Consumptive Use Values Root Distributions Group #5 /// Printed output contains not only the daily moisture properties and net fluxes, but also a listing of initial conditions, run parameters, and other input and controlling data. Tables 28 and 29 contain descriptions of the variables in each type of printed output. Detailed output from Program MOISTRE is written on a magnetic tape called TAPE 5 in the program. As presently compiled the program writes the value of the variables described in Table 30 on TAPE 5 at 0.1 day intervals, although with simple program modifications this interval could be changed. Blaney -Criddle Soil Group #2 Group Consumptive Use Data Initial Moisture Contents Group #4 Group #3 #1 Identification Water Application Control Data Parameters RESTART CAPABILITY The Moisture Flow Program was developed so that it may be executed in successive stages. Utilizing this capacity, the program can be executed for any period of time from LL to MM with the following restrictions in LL ( the starting day number) and MM (the final day number of the run): (a) 1 < LL < 365, (b) LL < MM < 365, (c) LL = first or 16th day of any month. Figure 22. Data card groups needed in Program MOISTRE. "real" (16), the decimal point may be punched on the data card anywhere within the field. If the data -name is "integer," no decimal point is permissable and the numeric value must be right justified within the field. Data -names which are alpha- numeric may contain either alphabetic or numeric characters. PROGRAM OUTPUT: Output from Program MOISTRE is of two types: (A) printed output, and (B) output written on magnetic tape (TAPE 5). An additional magnetic tape (TAPE 4) is used internally in the program and to restart Program MOISTRE at days other than day one. A description of the variables written on TAPE 4 is contained in the Re -Start Capabilities portion of this Users Manual. Re -start capability is provided by writing the values of the necessary re-start variables on magnetic tape (TAPE 4) on a daily basis. Therefore, if it is desired to re -start the Moisture Flow Program on day number LL and continue it through day number MM the following procedure should be used: a) Using appropriate control cards for the computer system skip forward through logical record LL 1 on the tape assigned as TAPE 4. b) Execute Moisture Flow Program for days LL to MM. The Moisture Flow Program will BACKSPACE to read the values of the necessary re -start variables from day LL 1 to be used as input for day LL. It should be noted that the values of the variables not designated as restart variables (See Table 31) will be reassigned from data cards or statement function (for diffusivity and conductivity relationships). The only input variables that will be over -ridden - - TABLE 20. Data card groups of the Moisture Flow Program. Group Program Served No. of Cards 1 Program MOISTRE 1 2 APPSA 5 Program MOISTRE Program MOISTRE Program MOISTRE Subroutine CONUSE 6 Subroutine CONUSE 3 7 Subroutine CONUSE 24 3 4 tö> General Description 1B 60>Q> lc 24 Print options, constants, boundary and initial condition options. Date and amount of water applications. Soil identification and horizon depths. Initial soil moisture content at each node (J). Input data for Blaney -Criddle method of computing crop consumptive use tabulated on a semi -monthly basis beginning Jan. 1. Fraction of roots occurring in each of top 6 feet of soil, one card for crop 1, crop 2, and crop 3. Semi- monthly consumptive use moisture removal amounts. AAPPS = the number of individual water applications. B See Table 23 for explanation of 0. cThe number of depth nodes (Q) is determined by the distance between the depth nodes (DELX) and the depth to the bottom of the deepest soil horizon, HOR(0), by the relationship Q = HOR(0)/DELX -{- 1 where Q is truncated because its data type is integer. Page 32 TABLE 21. Description of variables on data card comprising Data Card Group Columns Data Name Description Data Type Special Value 1- 5 6 -10 AA 11 -15 CC 16 -20 21 -25 LL MM 26 -30 BBC Integer Integer Integer BB Integer Integer Real Performance 1 1 1 1 < LL < 365 < MM < 365 LL 1 2 (any other) 31 -35 TBC Real 1 2 (any other) 36 -40 41 -45 YEAR CROP Integer Integer > 1 1 2 3 Integer Integer >0 TM TD Real Real Real Real TD < TM < TS TD < TM < TS TD < TM < TS SM Real TD 46 -50 51 -55 M 56 -60 DELX 61 -65 TS 66 -70 71 -75 76 -80 APPS 1. >0 < SM < TS Print parameters and constants. Print moisture contents daily. Utilize initial moisture contents from Group 4 data cards for internal soil nodes only. Starting day number (Jan. 1 = day 1). Last day number of run. Bottom boundary condition retained at TM. Bottom boundary condition retained at TS. Bottom boundary condition retained at this values. Top boundary condition initialized at TM. Top boundary condition initialized at TS. Top boundary condition initialized at this values. Year number. Utilize Blaney-Criddle formula to compute consumptive use for CROP = 1. Utilize Blaney- Criddle formula to compute consumptive use for CROP = 2. Use consumptive use constants on Data Card Group 7. Minimum number of time intervals per dayA. Number of water applications, (Number of Data Card Group 2 cards) . Distance between depth nodes (cm). Maximum moisture contents. Arbitrary moisture contents. Minimum moisture contents equal to the cut-off below which no further consumptive use can be withdrawn by the sink term. Arbitrary initial moisture contents for internal nodes if option CC is not used. ABased on present experience, M should not be less than 100. BAIL moisture contents are expressed as decimals. TABLE 22. Description of variables on data cards of Data Card Group 2. Columns Data Name Data Type Description 21 -22 MON(L) DATE(L) AMT(L) ADENT (L ( ) Integer Integer Real Month of water application. Day of month of water application. Amount of water application (cm). jI = irrigation Source of application: R rainfall 24 -25 31 -40 80 Alpha-numeric P - TABLE 23. Description of variables on data cards of Data Card Group 3. Data Name Data Type Description 1- 2 0 3 -10 IDENT Integer Alpha-numeric Real Number of soil horizonsA, (Number of Data Card Group 3 cards). Soil horizon identificationA. Depth from surface to lower boundary of horizon (cm) A. Columns 11 -20 HOR(N) Soil "horizons" referred to in this context do not correspond to morphological soil horizons. Program MOISTRE models moisture movement in uniform soils only, so soil "horizons" as referred to here have no function except to correspond to the "chemistry horizons" in the BiologicalA Chemical Program for convenience. Page 33 TABLE 24. Description of variable on data cards of Data Card Group 4. Columns Data Name Data Type Description 46 -51 TO(J) Real Initial soil moisture content of each depth node (J), including boundary nodes if option CC is used (Table 21). TABLE 25. Description of variables on each of the 24 data cards of Data Card Group 5. Columns 1 -10 11-20 21 -30 31 -40 Data Name Data Type Description MEANT1(I)A Real Pl (I)8 KA1(I)c KB1(I) D Real Mean air temperature in °F for each semi -monthly period. Percent of annual daylight hours occurring in each semi-monthly period. Real Blaney- Criddle semi-monthly crop consumptive use coefficient for crop Real Blaney -Criddle semi-monthly crop consumptive use coefficient for crop = 2. A For second semi -monthly For second semi -monthly c For second semi -monthly D For second semi -monthly E period period period period = 1. in each month this variable is named MEANT2 (I). in each month this variable is named P2(I). in each month this variable is named KA2(I). in each month this variable is named KB2(I). TABLE 26. Description of variables on each of the three data cards of Data Card Group 6. Data Name Data Type Description -10 KP(1)A Real Decimal fraction of roots located in top foot of soil profile. 11 -20 KP(2)A Real Decimal fraction of roots located in 2nd foot of soil profile. 21 -30 KP(3)A Real Decimal fraction of roots located in 3rd foot of soil profile. 31 -40 KP(4)A Real Decimal fraction of roots located in 4th foot of soil profile. 41 -50 KP(5)A Real 51 -60 KP(6)A Real Decimal fraction of roots located in 5th foot of soil profile. Decimal fraction of roots located in 6th foot of soil profile. Columns 1 AData name is KP(I) for crop = 1, KPI(I) for crop = 2, and KP3(I) for crop - 3. TABLE 27. Description of variables on data cards in Data Card Group 7. Columns Data Name Data Type Description 21-30 U Real Semi -monthly consumptive use moisture removal constants (inches /1/2 month)A. A I st - 15th is first half of each month, 16 - end of month is second half. Page 34 TABLE 28. Description of variables printed as initial conditions, run parameters, and constants if print option AA Data Name = 1. Description AA BB CC LL MM BBC TBC YEAR CROP See description of variables in Data Card Group 1 (Table 21) M APPS DELX TS TM TD SM = L = TME (L) L MON(L) DATE (L) - 1, APPS APPS APPS 1, APPS 1, APPS 1, AMT(L) ADENT (L) L L L IDENT N=1,0 = = Day number of water application. 1, See description of variables in Data Card Group 2 (Table 22). 23). HOR(N) N-1,0 See description of variables in Data Card Group 3 (Table TH(J) MEANTI(I J Initial soil moisture content of each depth node (J). KB1(I)D = I, Q 1=1,12 I=1,12 = 1, 12 1=1,12 UH(I) I KP(1)E 1= A PI (I)B KA1(I)c See description of variables in Data Card Group 5 (Table 25) . 1 = 1, Semi -monthly consumptive use moisture removal constants (cm /1/2 month) to be used if CROP = 3. 24 See description of variables in Data Card Group 6 (Table 1, 6 AFor B For c For DFor second semi -monthly period in each month, the variable is named second semi-monthly period in each month, the variable is named second semi -monthly period in each month, the variable is named second semi- monthly period in each month, the variable is named EData-name is KP(I) for CROP = 1, KP1(I) for CROP = 2, KP3(I) MEANT2(I). by restarting are the initial soil moisture contents and initial values for the upper and lower boundary conditions. The complete data deck must be used. If it is desired to execute the Moisture Flow Program beyond 365 days, the following procedure is recommended: (a) Generate through 365 days for previous year. Lions are over-ridden by the P2(I). KA2(I). KB2(I). for CROP rent year. . through MM = 365. It should be emphasized that the mass balance computations are based on initial conditions at the start of the original simulation, even though the values of these condi- 3. "re -start variables." 1f the original inputs are not changed, the mass balance check will be valid following re- starts even at times greater than one year. PROGRAM INTFACE (b) Change data cards for inputs appropriate for cur(c) Skip back on re -start tape (TAPE 4) correct number of logical records (365) (d) Generate current year by running from LL = 1 26). Program INTFACE is an interfacing program to convert the output from the Moisture Flow Program (TAPE 5) to the appropriate form for input to the Biological -Chemical Program (TAPE 1). Because of differences the length of ¿X in the two programs, it is not feasible to generalize the program, so the user must write an interfacing program similar to Program INTFACE as listed as an example in Appendix A. Page 35 TABLE 29. Description of variables printed daily. Data Name Description II Day number. Decimal fraction of day II completed. Number of month corresponding to IÌ. Day of month corresponding to II. Cumulative leachate at end of day II (cm). Mass balance check on CL (cm). Cumulative infiltration at end of day II (cm). Cumulative consumptive use (evapotranspiration) removed at end of day II (cm). Soil moisture storage difference at end of day II relative to initial moisture content of profile (cm). Number of time intervals required in day II. Soil moisture content at end of day IIA. Day number of water applicationB. Amount of water (cm) to infiltrate at start of day = TME(L)B. XT MONTH IDTE CL CHECK ETS ET DIF I TN(J) TME(L) = 1,Q L = 1, APPS J HED only if BB = 1 (Table 21). Printed only at start of day = TME(L). A Printed B TABLE 30. Description of variables written on magnetic tape (TAPE 5) at the end of each output periodA. Data Name Description CI Day Number. Decimal fraction of day II completed. Number (subscript) of depth node. Moisture content of each depth node (J) (cm3 /cm3). Amount of deficit soil moisture (cm) for the output periodA. Net soil moisture flux between depth nodes (J) and (J + 1) for the output period (cm) A, where positive values indicate net downward fluxes. Cumulative infiltration (cm), from (downward surface flux). CL HED ETS Cumulative leachate (cm). Amount of water remaining to infiltrate (cm). Cumulative infiltration (cm), from (all surface flux). II XT J TN(J) Z(J) SF (J) U(J) = 1,Q J=1,Q J=1,Q J J=1,Q Semi -monthly consumptive use moisture rate for each depth node (J) (cm /day)B. AOutput period is presently 0.1 day, which corresponds to the input requirements of the Biological-Chemical Program. B 1st - 15th is first half of each month, 16 - end of month is the second half. Description of the variables written on TAPE 5 and TAPE 1 are continued in the Users Manual for the Moisture Flow Program and Biological-Chemical Program, respectively. The following discussion points out some of the principles essential to this TAPE 5 - TAPE 1 conversion in the order the variables are written on TAPE 1. (a) II, M, M are non-essential dummy variables reserved for future use. (b) SEGVOL(J) is volume of water in each soil segment of Biological-Chemical Program. It is cornputed from a weighted average of the moisture content of all nodes (from Moisture Flow Program) in that segment. Page 36 (c) MOISIN(J) is volume of moisture moving across the upper boundary of each soil segment (in Biological- Chemical Program). It is computed by averaging the values for soil moisture flux (from Moisture Flow Program) at the two nodes nearest to the segment boundary. (d) MOISOUT(J). Analogous to (c) except MOISOUT(J-1) = MOISIN(J). (e) TEN(J). Average soil moisture tension (cm of H2O) of each soil segment. Correct numerical values should be computed from the moisture content tension relationship only at times when the TABLE 31. Description of variables designated as re -start variables. These variables are re- initialized from TAPE 4 when the Moisture Flow Program is re- started. Data Name Description TN(J) FN(J) Soil moisture content of each depth node (J). Soil moisture flux between depth nodes (J) and (J CI + 1) which occurred during the previous time interval where positive values indicate net downward fluxes. Cumulative leachate (cm). Mass balance check (cm) on cumulative leachate. Largest flux rate [FN(J) /DELI] during last time interval of previous run. Subscript determining next moisture application. Quantity of water (cm) remaining at soil surface to infiltrate. Soil moisture contents at each depth node (J) that are anticipated to exist at the end of the first time interval of the restart run. Cumulative infiltration (cm), from (downward surface flux). ETS Cumulative flux at the soil surface (cm), from ET Cumulative consumptive use (evapotranspiration) of soil moisture (cm). CL CHECK IR L HED ANT (J) tension is greater than 10 bars. Otherwise any value in the range of 0 < TEN(J) < 10,300 cm. yields identical results. (f) U(J) as written in Tape 5 is volume of water consumed /unit volume of soil /day. It must be converted to volume of water consumed /soil segment/ time interval for the Biological -Chemical Program. This conversion is necessary only if the variable CROP (in Biological -Chemical Program) is equal to 1. BIOLOGICAL-CHEMICAL PROGRAM INTRODUCTION: The purpose of this manual is to provide the user with detailed operating instructions for the Biological-Chemical Program. The manual is written with the assumption that the user has read the sections of this report pertaining to the program's concepts and theoretical basis. References are made to earlier passages and diagrams to clarify certain technical points. The manual includes general and specific discussions of the types of data (e.g. soil data, moisture flow data, etc.) needed to run the program as well as the types of output data which may be obtained. Use or generation of all input and output media such as printed output, data card, and magnetic tapes and discs, is discussed in detail. The input and output for a sample run are included in the Appendix to illustrate use of the program. (all surface flux). PROGRAM LANGUAGE AND COMPILATION: The source program is written in FORTRAN IV computer language for Control Data Corporation 6000 series machines (16) . Compilation has been successfully accomplished using the RUN and FTN fortran compiler versions for the C.D.C. 6400 located at the University of Arizona, Tucson, Arizona, and the FTN fortran compiler version for the C.D.C. 3800 located at N.O.A.A., Boulder, Colorado. The amount of machine space and time needed to compile and execute the program is highly machine dependent. However, the program was compiled on the C.D.C. 6400 under FTN fortran using a field length of approximately 70 K octal words (60 binary bits each). The compiler output was loaded and executed with a field length of approximately 66 K octal words. Compilation time was about 40 seconds. PROGRAM INPUTS: Input media to the Biological- Chemical program consist of data cards and /or magnetic tape. Basic control data, soils data, fertilizer and organic matter application data, and any plant uptake data are read in from cards. Moisture flow data including irrigation and rain inputs, flow between soil segments, soil moisture content and consumptive use data are read from magnetic tape. An option also allows this data to be read from cards. The following section (Section No. 1) gives a detailed discussion of the punch card inputs. Magnetic tape inputs are discussed beginning on page 46. Page 37 Section No. 1 Group X16 Plant Uptake of Nitrogen 15 Root Distribution Grou P Or.anic A.plications Grou. #14 Fertilizer Application Group #13 CARD INPUTS Irrigation Water Application Dates Organic Application Dates Group #11 Fertilizer Application Dates Group #10 Group #12 The card input consists of 16 basic card groups of one or more cards each (Figure 23) . All groups except numbers 7, 8, 9, 15, and 16 must be present whenever a run is made. Inclusion of Group 7 cards allows the program to be run with a set of constant flow data for each time step. For example, a run can be made involving constant soil moisture content and /or moisture movement with respect to each soil segment (see page 5 for details concerning segments and horizons) When this group is present, TAPE 1 (input from the Moisture Flow Program) is not read. Group 7 must be absent if TAPE 1 is being read. Card Group 8 must be present whenever a restart data deck or restart data written on TAPE 3 are not available. When Group 8 is present, the program must be started from the initial starting time. Group 9 must be absent if Group 8 is present. Card Group 9 allows the program to be restarted using the card deck generated in a previous run. Inclusion of Group 9 dictates that Group 8 can be omitted. Groups 15 and 16 must be included if plant root distributions and plant uptake of nitrogen data are to be read from cards. A detailed description of each card group follows Figure 23. Group Restart Data #4 Group Group Group Initial #8 7 #6 Soil Analysis Flow Data Irrigation ater Analysis I Tempera ure Jata #5 Group Component Horizon Depths 4 Group Temperature Horizon Depths #3 Group Control Cards #2 Group Group . #1 Title Card Optional Figure 23. Card groups needed in Biological-Chemical Program data deck. Page 38 CARD GROUP NO. Title Card 1 of 1 Columns 1 Data Name on Printed Output -80 1 Card Data Type Description ALPHA Any title desired on printed output. CARD GROUP NO. 2 Control Cards Card 1 of Columns 1- 5 6 -10 3 Data Name on Printed Output Data Type Description SOIL SEGMENT SIZE REAL Soil segment size (cm). See page 41 for details. TIME INTERVAL REAL Time interval size (days) corresponding to intervals for moisture flow on Tape 1. REAL Ratio of water to soil in the soil extract (gm water /gm soil). 1 REAL Convergence criterion for nitrogen transformation subroutine. See page 41 for details. Suggested values are in the range 0.1 - 10.0 ppm nitrogen. CONVERG 2 REAL See page 41 Convergence criterion for ion exchange subroutine. "2 -5 1 X 10 for details. Suggested values are in the range 1 x 10 SIZE 11 -15 1.6 -20 21 -25 XTRACT CONVERG - moles /liter. REAL Shut -off criterion for nitrogen transformation subroutine. See page 41 for details. Suggested values are in the range 0.1 - 2.0 ug /soil segment/time step. CHECK REAL Shut -off criterion for ion exchange subroutine. See page 41 for details. Suggested values are in the range 1.0 - 5.0 ug /soil segment /time step. 36-40 REDUCE REAL Number of time intervals to be used within each TIME INTERVAL SIZE mentioned above should any nitrogen mass deficits occur. See page 41 for details. Suggested values are in the range 5 -10. 41 -45 UPTAKE(NO3) REAL Fraction of total plant uptake of nitrogen as NO3 -N. A suggested value is 0.95. As NO; -N mass --* 0.0 plant uptake of NO-3-N -* 0.0 regardless of plant uptake imposed 26 -30 CHECK 31 -35 1 on system. 46 -50 UPTAKE(NH4) REAL Fraction of total plant uptake of nitrogen as NH4 -N. A suggested value is 0.05. Fraction as NO3 -N plus fraction as NH4 -N must equal unity. The same relationship for NO3 -N holds for NH4 -N uptake with respect to the zero mass boundary condition. 51 -55 None REAL Plant -N uptake constant for use with consumptive use values (if used) . Page 39 Card 2 of 3 Columns Data Name on Printed Output Data Type Description Starting day of run relative to time reference date. (e.g. if reference date is January 15 and starting day for run is January 21, the relative starting day would be day 7). Termination day of run relative to time reference date. Number of soil chemistry horizons (must be in range 1 to 9 inclusive) . If 1, consumptive use used to determine N- uptake by plants. If 2, reserved for future use. If 3, read plant N- uptake data from cards (see card groups 15 and 16) . Number of temperature horizons (must be in range 1 to 4 inclusive) Number of weekly temperature data cards (see group 5) Print interval (days) for predicted soil chemistry data. Time interval within a day on which the IPRINT and IMASS print options are to be activated. Write interval (days) for output to TAPE 2 (see SECTION 3) . If 0, program is to be run from initial input deck. If 1, program is to be restricted from tape of restart deck. If 0, no restart data deck will be punched. If 1, a restart data deck will be punched. (A restart tape (No. 3) is always written) If 0, program is to be restarted from TAPE 3, or started from initial data. If 1, program is to be restarted from cards (See Group 9) If 0, moisture flow data is read from TAPE 1. If 1, moisture flow data is read from cards (See Group 7) . Reference date in reference month (e.g. March 21 would be STARTING DAY = 21) See below. Reference month. Month to which all starts of the program are referenced (e.g. if reference month is March, STARTING MONTH = 3) Year for this run (e.g. if this is the third year being run, YEAR = 3) 1- 5 RELATIVE STARTING DAY INTEGER 6 -10 INTEGER 11 -15 RELATIVE TERMIN DAY NO. OF CHEMISTRY 16 -20 HRZNS CROP INTEGER INTEGER NO OF TEMP HRZNS NT 21 -25 26 -30 INTEGER . INTEGER . 36 -40 IPRINT JPRINT INTEGER INTEGER 41 -45 INK INTEGER 46 -50 IRERUN INTEGER 51 -55 IPUNCH INTEGER 31 -35 . INTEGER IREADP 56 -60 . 61 -65 ITEST INTEGER 66 -70 STARTING DAY INTEGER 71 -75 STARTING MONTH INTEGER . YEAR 76 -80 INTEGER . Card 3 of Columns Data Name on Printed Output Data Type Description 1- 5 ISTOP INTEGER 6 -10 IMASS Year when run terminates (e.g. if run is to terminate after 3 years and starts with year 3, ISTOP = 5) . Print interval (days) for summary of nitrogen balance for system. If 1, basic control card data are printed. If 0, printing of above is suppressed. If 1, input data are printed. If 0, printing of above is suppressed. 3 11 -15 IPRINT I INTEGER INTEGER 16 -20 IPRINT J INTEGER Page 40 ADDITIONAL DETAILS FOR CARD GROUP 2 SOIL SEGMENT SIZE. Soil segment size (or DELX, see Figure 1) must be in the range [depth (cm) to water table/ (25 1)] < SOIL SEGMENT SIZE < the size (cm) of the largest chemistry or temperature horizon. Here the 25 refers to array size currently used in the program. CONVERGE 1. This constant determines the accuracy of the nitrogen changes computed in Subroutine TRNSFM. A smaller value will increase accuracy and program execu- - tion time. CONVERGE 2. This constant determines the accuracy of mass changes in the system computed in subroutine XCHANGE. A smaller value will increase accuracy and program execution time. CHECK 1. This constant is used in subroutine CHK to determine if Subroutine TRNSFM should be called for that time step or by- passed and the previously computed nitrogen changes used. If the rates of change for nitrogen are less than CHECK 1, TRNSFM is by-passed. However, TRNSFM is called at least once each day to avoid possible "drift" in the calculations. CHECK 2. This constant is used in Subroutine CHK to determine if Subroutine XCHANGE should be called for that time step or by- passed, in which case previously computed changes due to ion exchange, etc. are set equal to zero. XCHANGE is called at least once each day. REDUCE. This constant allows the program to use smaller time increments than those specified by TIME INTERVAL SIZE for cases where the system becomes deficient in nitrogen mass. A larger value of REDUCE tends to minimize mass balance errors which occur as the system becomes mass deficient. CARD GROUP NO. 3 Temperature Horizon Depths Card 1 of Columns 1 Data Name on Printed Output Data Type Description 1- 5 TEMPERATURE HRZN DEPTHS REAL Depth (cm) from surface to bottom of 1st temperature horizon. 6 -10* Same as above REAL Depth (cm) from surface to bottom of 2nd temperature horizon (if it exists) . *The program allows the inclusion of up to 4 temperature horizons. If included, the depths, for numbers 11 -15 and 16 -20, respectively. 3 and 4 would be punched in columns CARD GROUP NO. 4 Chemistry Horizon Depths Card 1 of Columns 1 Data Name on Printed Output Data Type Description 1- 5 CHEMISTRY HORIZON DEPTHS REAL Depth (cm) from surface to bottom of first chemistry horizon. 6 -10* Same as above REAL Depth (cm) from surface to bottom of second chemistry horizon.** *The program allows inclusion of up to 9 chemistry horizons. If included, the depths for numbers 3, 4, 5, 6, 7, 8, and columns 11 -15, 16 -20, 21 -25, 26 -30, 31 -35, 36-40, 41 -45, respectively. * *If only one chemistry horizon is desired, only one need be included. Page 41 9 would be punched in CARD GROUP NO. 5 Temperature Data Card 1 of NT* Columns Data Name on Printed Output 1- 2 3 -10 10-20** Description Data Type TEMPERATURE (DEG C) REAL Same as above REAL Card identification (not read by program). Weekly temperature ( °C) for upper most (first) temperature horizon. Weekly temperature ( °C) for second temperature horizon.*** *NT is the number of temperature data cards. Each card contains weekly data for all temperature horizons. * *The program allows inclusion of up to 4 temperature horizons. If included, temperature data for horizons columns 21 -30 and 31 -40, respectively. * * *If only one temperature horizon is desired, only one need be included. 3 and 4 would be punched in Note: The first temperature data card should correspond to the week beginning with the reference date (see SECTION No. 5 for exceptions). CARD GROUP NO. 6 Irrigation Water Analysis Card 1 of Columns 1 1- 5 6 -10 11-15 16 -20 21 -25 26 -30 31 -35 36-40 41 -45 Data Name on Printed Output Data Type Description REAL REAL REAL REAL REAL REAL REAL REAL REAL NI-1+4 (all units in meq /L of the species shown). IRRIGATION WATER ANALYSIS Same as above Same as above Same as above Same as above Same as above Same as above Same as above Same as above NO 3 Ca" Na+ Mg ++ HCO -3 CíCO -3 S0 -4 Note: All irrigation water is assumed to have same analysis. CARD GROUP NO. 7 Moisture Flow Data Card 1 of NS* Columns Data Name on Printed Output Data Type Description -10 I1 -20 SEGVOL None REAL REAL 21 -30 None REAL 31 -40 None REAL 41 -50 None REAL Volume of water in segment (cc). Water movement across upper boundary of segment (cc /time step ) * *. Water movement across lower boundary of segment (cc /time step) * *. Average moisture tension (cm) over time step. (tensions shown as negative) . Plant water uptake (cm /time step /soil segment). 1 *NS is the number of moisture flow data cards. There must be a card for each segment including No. see page 125. * *Positive sign for downward flow, negative for upward flow. Page 42 1. For details in computing NS, CARD GROUP NO. 8 Initial Soil Analysis Card 1 of NC* Columns Data Name on Printed Output Data Type Description (Units in meq /L of species shown unless otherwise noted) NH +4 (soluble form) NO-3 UREA 1- 5 INITIAL SOIL ANALYSIS REAL 6-10 Same as above Same as above Same as above REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL 11 -15 16 -20 21 -25 Same as above 26-30 31 -35 36-40 41-45 46 -50 51 -55 56 -60 61 -65 Same Same Same Same Same None None None 66 -70 71 -75 None None REAL REAL 76 -80 None REAL as above as above as above as above as above Ca" Na+ Mg ++ HCOCICO -3 S0 =4 Exchange Capacity (meq /100 gm soil). Gypsum (meq /100 gm) soil. If 0.0, no lime is present in soil. If 1.0, lime is present in soil. Bulk Density (gm /cc of soil). Soil organic matter (ug /gm soil). This refers to entire mass of organic matter not to the organic nitrogen. The assumption is made in the program that the organic matter is 40% carbon on a dry weight basis. Carbon-Nitrogen ratio of organic matter (e.g. 40:1 would be punched as a 40.0) . *NC is the number of chemistry horizons. CARD GROUP NO. 9 Restart Data This data group is punched by the program during a previous run. See page 125 for details. The punch /read format is ( 415/,( 6E13. 5/6E13.5/6E13.5/6E13.5/E13.5)). CARD GROUP NO. 10 Fertilizer Application Dates Card 1 of 1** Columns 1- 5 Data Name on Printed Output FERTILIZER APPLICATION DATES 6 -10 Same as above 11 -15* Same as above Data Type Description INTEGER INTEGER INTEGER Number of fertilizer applications. First application day relative to reference starting date. Second application day relative to reference starting date. *The program allows inclusion of up to 25 fertilizer application dates. The same format, I5, is used for any additional dates desired. * *A second card may be used if needed (i.e. if the number of applications exceeds 15, in which case the I5 format still applies. Page 43 CARD GROUP NO. 11 Organic Matter Application Dates Card 1 of 1 Columns Data Name on Printed Output 1- 5 6 -10 11 -15* ORGANIC MATTER APPLICATION DATES Same as above Data Type Description INTEGER INTEGER Number of organic matter applications. First organic matter application day relative to reference date. INTEGER Second organic matter application day relative to reference date. *The program allows inclusion of up to 5 organic matter application dates. If included, application dates for applications 3, 4, and punched in columns 16 -20, 21 -25, and 26 -30, respectively. 5 would be CARD GROUP NO. 12 Irrigation Water Application Dates Card 1 of 1 ** Columns Data Name on Printed Output Data Type Description 1- 5 None INTEGER Number of irrigations. 6 -10 IRRIGATION WATER APPLICATION DATES INTEGER First irrigation day relative to reference date. INTEGER Second irrigation day relative to reference date. 11 -15* Same as above *The program allows inclusion of up to 25 irrigation dates. If included, applications 3 -25 would follow the same 15 format. * *A second data card may be needed if more than 15 irrigation dates are used. CARD GROUP NO. 13 Fertilizer Applications Card 1 of NF* Columns Data Name on Printed Output REAL 1- 5 6 -10 Data Type FERTILIZER APPLICATIONS 11 -15 Same as above REAL REAL 16 -20 Same as above Same as above Same as above Same as above REAL REAL REAL REAL 21 -25 26 -30 31 -35 Description All units in lbs /acre of species shown unless otherwise labeled. Depth (cm) of a uniform fertilizer application. If 0.0, a surface application is indicated. NI-I+4 Urea (NH2-C-NH2) NO3 a Ca" SO -4 CO 3 *NF is the number of fertilizer applications. The maximum number allowed in the program is 25. Page 44 CARD GROUP NO. 14 Organic Matter Applications Card 1 of NO* Columns Data Name on Printed Output 1- 5 6 -10 Data Type Description REAL Depth (cm) of uniform organic matter application. (Surface applications are not allowed.) Carbon:Nitrogen ratio of organic matter (e.g. 40:1 would be punched as a 40.0) Organic matter added (lbs /acre) as oven dry weight. C:N RATIO REAL ORGANIC MATTER APPLICATIONS REAL . 11-15 *NO is the number of organic matter applications. The maximum number allowed in the program is 5. CARD GROUP NO. 15 Plant Root Distribution Card 1 of Columns I Data Name on Printed Output Data Type Description PLANT ROOT DISTRIBUTION REAL Fraction (decimal) of plant roots from 0 -1 ft. depth. 11 -20 Same as above 21 -30 Same as above 31 -40 Same as above 41 -50 Same as above 51 -60 Same as above REAL REAL REAL REAL REAL Fraction from 1' - 2'. Fraction from 2' - 3'. Fraction from 3' - 4'. Fraction from 4' - 5'. Fraction > 5'. 1 -10 Note: Plant root distribution is independent of time. If roots do not extend to 5', use zero fractions for roots below their deepest extension. CARD GROUP NO. 16 Plant Uptake of Nitrogen Card 1 of NP* Columns -10 11 -20 Data Name on Printed Output Data Type Description Space for card identification. 1 * PLANT UPTAKE OF NITROGEN Plant uptake of nitrogen (lbs -N /acre/semi- monthly). REAL *NP is the number of semi -monthly ** plant uptake data cards. The program requires that 24 cards be present, even if not all of them are used. *Semi- monthly means the period from the 1st day thru the 15th day or from the 16th day thru the last day of the month. The 1st data card begins with the semi -monthly period containing the reference starting date (See page 113) Remaining data cards contain data for consecutive semi -monthly periods taken chronologically from the 1st. . Page 45 Section No. 2 TAPE INPUTS Tape input to the Biological -Chemical program consists of two optional tapes written in binary. TAPE i contains moisture flow data written by program 1NTFACE. An alternate procedure is to input moisture data on cards. In this case a single set of constant moisture data is read. TAPE 3 may be read to restart the program after a previous run. This tape is always written at the conclusion of a run. Unless a magnetic tape is equipped to tape unit 3, the binary data is written on a disc or drum. Disc or drum data may be lost at the conclusion of a run. The alternative to a restart from TAPE 3 is a restart from data cards. Page 46 Logical Record l of NR Field No. TAPE NO. Data Name on Printed Output Data Type Description Reserved for future use. Reserved for future use. Reserved for future use. Current volume of water (cc) in Jth* soil segment. Moisture flow (cc /time step) into the Jth soil segment. Moisture flow (cc /time step) from the Jth soil segment. Average current moisture tension (cm H2O) for Jth segment (sign ±). Consumptive use (cc /time step) for the Jth segment. 4 CMH2O 5 6 7 None None None INTEGER INTEGER INTEGER REAL REAL REAL REAL 8 None REAL 1 2 3 1 - *This sequence of 8 fields is repeated Q ** times per logical record. * *Q is the total No. of segments. Its value may be computed using the algorithm outlined on page NR is the number time steps for which data is written on TAPE 1. Logical Record 1 of 1 Field No. TAPE NO. 3 Data Name on Printed Output Data Type Description 16 17 None None None None None None None None None None None None None None None None None INTEGER INTEGER INTEGER INTEGER REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL 18 19 None None 20 None 21 None None None None None None None None None REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL Restart counter for plant uptake data. Restart counter for fertilizer application data. Restart counter for organic matter applications data. Restart counter for temperature data. Ug of NH4 -N contained in Jth** segment. Ug of NOS-N contained in Jth segment. Ug of Urea -N contained in Jth segment. Ug of Ca ++ contained in Jth segment. Ug of Na+ contained in Jth segment. Ug of Mg ++ contained in Jth segment. Ug of HCO-3 contained in Jth segment. Ug of Cl- contained in Jth segment. Ug of C0 =3 contained in Jth segment. Ug of S0 =4 contained in Jth segment. Exchange capacity of Jth segment. Gypsum concentration in Jth segment (moles /L). If 1.0, lime is present in Jth segment. If 0.0, lime is not present in Jth segment. Soil bulk density of Jth segment. Ug of organic matter just applied to Jth segment. C:N ratio of organic matter in Jth segment. Ug of organic -N in Jth segment. Residue nitrogen in Jth segment (Ug /g). Residue carbon in Jth segment (Ug /g). Exchangeable Ca ++ in Jth segment (moles /g). Exchangeable Mg ++ in Jth segment (moles /g). Exchangeable Na' in Jth segment (moles /g). Undissociated CaSO4 in Jth segment (moles /L). Undissociated MgSO4 in Jth segment (moles /L). Exchangeable NH +4 in Jth segment (moles /g). 1 2 3 4 5* 6 7 8 9 10 11 12 13 14 15 22 23 24 25 26 27 28 29 *Fields No. 5 -29 inclusive are repeated Q times in each logical record. Q is the number of segments and may be determined using the algorithm on this page. **The segments begin with J = 1 and end with J = Q. The algorithm for computing Q may be written as follows. Q = DEPTH to W.T. /DELX + 1.1, where any fraction is dropped in determining the final value for Q. Page 47 Section No. 3 CARD OUTPUTS Card output from the program consists of data needed to restart a run after a previous execution. This card deck is generated only if the proper control card request has been made (see Card Group No. 2) . No card deck is punched if a program run terminates abnormally (e.g. a fatal error occurs) . A discussion of the punch format is presented in Section No. 1, under Card Group No. 9. See TAPE 3, page 123 for variable descriptions. Page 48 Section No. 4 TAPE OUTPUTS Tape output from the Biological-Chemical program con- sists of one BCD (TAPE 2) and one binary (TAPE 3) file. TAPE 2 is formated in such a manner that the file can be copied to the print file with single spacing. TAPE 3 contains restart data which may be read into the program to restart a previously terminated run. TAPE NO.2 Logical Record 1 of NR Data Name on Printed Output Data Type None None None None None None None None None None None None REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL None None None None None None None None None None REAL REAL REAL REAL REAL REAL REAL REAL REAL REAL 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 Description Space (blank) . Water leached since start of run (cc). Water leached since previous record was written (cc /cm2). NO3 -N leached since start of run (ug /cm2). NO3 -N leached since previous record was written (ug /cm2). NH4 -N leached since start of run (ug /cm2). NH4 -N leached since previous record was written (ug /cm2). Urea-N leached since start of run (ug /cm2). Urea-N leached since previous record was written (ug /cm2). Ca ++ leached since start of run (ug /cm2). Ca ++ leached since previous record was written (ug/cm2). Na+ leached since start of run (ug /cm2). Na+ leached since previous record was written (ug/cm2). Space (blank). Mg ++ leached since start of run (ug /cm2). Mg ++ leached since previous record was written (ug /cm2). HCO -3 leached since start of run (ug /cm2). HCO -3 leached since previous record was written (ug /cm2). Cl- leached since start of run (ug /cm2). Cl- Ieached since previous record was written (ug /cm2). CO -3 leached since start of run (ug /cm2). CO -3 leached since previous record was written (ug /cm2). SO -4 leached since start of run (ug /cm2). SO -4 leached since previous record was written (ug /cm2). NR is the number of records written on TAPE 2. The write interval (i.e. time between write operations is specified by the user (see Card Group No. 2). Note: The format used in writing each logical record is (IX, 12E10.3). The data on TAPE 2 may serve as input to routines which consider saturated flow and saturated chemistry. Page 49 Section No. 1. 2. 3. 4. 5. 6. 5 HINTS ON PROGRAM USE Be sure core is set to zero before program is loaded. The program does not initially rewind TAPE 1 and TAPE 2. The user is responsible for the initial positions of these tapes. An end -of -file is written on TAPE 2 at the conclusion of a run. This means that output from several runs may be stored as separate files on the same or individual tapes. A run which exits due to a time limit or other error will not produce a restart deck or tape. The number of temperature cards may be reduced when making a restart run by altering the value of the number contained in Field No. 4 of the restart deck or tape. The number placed there by the program is the number of cards or records to skip in order to locate the correct temperature data card. If no plant uptake of N is required, set CROP equal to 1 and leave columns 51 -55 of the first control card blank. In this case, CARD GROUP 16 may be omitted from the deck. Page 50 APPENDIX A PROGRAM LISTINGS Page 51 LISTINGS FOR MOISTURE FLOW PROGRAM MOISTR£ MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE CONDUCTIVITY ANO DIFFUSIVITY FUNCTIONS. MOISTRE NOTE- -CARDS IN THIS SECTION MUST BE CHANGED FOR DIFFERENT SOILS. MOISTRE *EXP(35.8 * * 10. * *( -5.) Z) CONDUCT(Z) =4.6T MOISTRE / (Z *Z) * EXP(35.8*Z - 0.236/Z) OIFUSEI(Z) =6.15 * 10. * *( -4.) MOISTRE *EXP(25.3 * Z) DIFUSE2(Z) =6.33 * 10. * *( -1.) *EXP( -0.9 MOISTRE * Z) OIFUSE3(Z) =2.72 10. * *( +4.) * MOISTRE READ PRINT OPTIONS, RUN PARAMETERS, WATER APPLICATIONS, PROFILE DA MOISTRE READ 100 ,AA,BB,CC,LL,MM,80C,TBC,YEAR, CROP,M,APPS,DELX,TS,TM,TD,SM MOISTRE MOISTRE READ 106,(MON(L), DATE (L),AMT(L),ADENT(L),L= 1,APPS) MOISTRE READ 101,(O,IDENT,HOR(N),N =1,0) MOISTRE MOISTRE COMPUTATION OF TIME OF WATER APPLICATIONS. MOISTRE DO 600 L =1,APPS MOISTRE AMT(L)= AMT(L)*'2.54 MOISTRE START =0 MOISTRE DO 29 L= 1,APPS MOISTRE THE (L)= DAY(DATE(L),START,MON(L)) MOISTRE MOISTRE ESTABLISH MOISTURE DISTRIBUTION AND INITIALIZE CERTAIN VARIABLES. MOISTRE DELTM =1. /M MOISTRE KSATD= CONOUCT(TS) MOISTRE DELT = DELTM MOISTRE Q= HOR(0) /DELX +1.1 MOISTRE L =1 MOISTRE G =DELX MOISTRE IF(90C.EQ.1)88C =TM MOISTRE IF(BBC.EQ.2)3BC =TS MOISTRE IF(TBC.EQ.1)TBC =TM MOISTRE IF(TBC.EQ.2)TBC =TS MOISTRE IR =1000. MOISTRE HED =CL= CHECK= ETS= ET= CI =FN(1) =DIF= CONST= SF(1) =0.0 MOISTRE X=10. * *( -10.) MOISTRE TN(1) =TBC MOISTRE INITIALIZE THETA AS CONSTANT WITH DEPTH. MOISTRE 00 43 J =2,Q MOISTRE SF(J) =0.0 MOISTRE TN(J) =SM MOISTRE IF(J.EQ.Q)GO TO 43 MOISTRE TN(J +1) =SM MOISTRE CONTINUE MOISTRE TN(Q) =BBC MOISTRE IF DESIRED, REINITIALIZE THETA WITH VALUES FROM DATA CARDS. MOISTRE DO 15 J =1,Q MOISTRE READ 104,TO(J) MOISTRE IF(CC.EQ.1)TN(J) =TO(J) MOISTRE TH(J) =TN(J) MOISTRE CONTINUE MOISTRE DO 20 J =1,Q MOISTRE Z(J)_0.0 MOISTRE IF(J.EQ.Q)GO TO 20 MOISTRE ANT(J)= (TN(J)+TN(J +1))/2. PROGRAM MOISTRE(INPUT,OUTPUT,TAPE4,TAPE5) DIMENSION HOR(9),Z(60),MON(30), DATE (30),AMT(30),TME(30),SF(60), 2T0(60),TN(60),FN(60), ANT( 60), K( 60) ,D(60),S(60),E(60),F(60),U(60), 3UH(24),KP3(6),TH(60),AOENT(30) DIMENSION MEANT1( 12), MEANT2( 12), KA1 (12),KA2(12),K81(12),KB2(12), 1P3(12),P4(12),KP(6),KP1(6) COMMON /XYZ /IDTE,MONTH,UH, KP3, KP, KPi ,MEANT1,MEANT2,P3,P4,KA1,KA2,K8 11,K82 INTEGER O,P1,P2,Q,APPS,DATE,YEAR, DAY,CROP,TME,AA,BB,CC,ADENT, 1START REAL K, IR,KSATD,KP,KP1, KP3 ,MEANTI,MEANT2,KA1,KA2,KB1,KB2 C C C C 600 29 C C 43 C 15 Page 52 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 MOISTRE MOISTRE MOISTRE 16 MOISTRE MOISTRE MOISTRE LOOP. LENGTH WITHIN TOTAL RUN DAYS C MOISTRE 00 32 II =LL,MM MOISTRE I =0 MOISTRE XT= 10.* *( 10.) MOISTRE CALL THEOATE(START,II) MOISTRE OR SIXTEENTH FIRST ON BE RESTARTED PROGRAM THIS ONLY CAN NOTE THAT C MOISTRE IF (IDTE.EQ.1.OR.IDTE.E(1.16)11,12 MOISTRE DO 3 J =1,Q 11 MOISTRE THAN 0 GREATER NODE FOR J /DAY EACH CM IS IN (U(J)) USE C----- CONSUMPTIVE MOISTRE IF(II.EQ.LL.AND.J.EQ.1)CALL CONUSE(CROP,DELX,J,U(J)) MOISTRE CALL CONUSEI(CROP,DELX,J,U(J)) MOISTRE 3 CONTINUE MOISTRE IF(II.EQ.LL)GO TO 10 MOISTRE MOISTRE READ RE -START VARIABLES FOR START OF EACH DAY, EXCEPT DAY ONE OF C MOISTRE THE FIRST YEAR. C MOISTRE 12 IF(II.EQ.167.AND.YEAR.EQ.67)GO TO 1 MOISTRE IF(II.EQ.1.ANO.YEAR.E0.1)GO TO 1 C 12 MOISTRE 8ACKSPACE4 MOISTRE =1,Q) ,L,HED,ANT(J),CI,ETS,ET,J IR CHECK, READ(4)(TN(J),FN(J),CL, MOISTRE MOISTRE DAY. OF EACH INITIALIZE HEU AT START C MOISTRE IF(II.EQ.TME(L))30,34 1 MOISTRE 30 IF(HED.GT.0.0)HED =HED +AMT(L) MOISTRE AMT(L) IF(HED.LE.0.0)HED= MOISTRE L =L +1 MOISTRE IR =100. MOISTRE IR =1000. MOISTRE PRINT 102,II,HEO MOISTRE MOISTRE TIME INTERVALS WITHIN EACH DAY LOOP. C MOISTRE 34 DO 21 J =1,Q MOISTRE TO(J) =TN(J) 21 MOISTRE C COMPUTE SIZE OF TIME INTERVAL, DELI. MOISTRE I =I +1 MOISTRE OELTO =DELT MOISTRE IF(X.GE.0.i)X= 10. * *( -10.) MOISTRE DELT= AMIN1(DELX *0.035 /IR,DELTM) MOISTRE IF(DELT.LT.0.00001)OELT =0.00001 MOISTRE IF( HEO. GT .0.0.AND.KSATO *DELT.GT.HED)OELT =HED /KSATD MOISTRE IR= 10. * *( -10.) MOISTRE IF(X +DELT.LE.0.1)G0 TO 4 MOISTRE DELT =0.1 MOISTRE X =X +DELT 4 MOISTRE XT =XT +DELT +10. * *( 10.) MOISTRE Y= 0.70 *DELT /DELTO MOISTRE MOISTRE C EXAMINE UPPER BOUNDARY CONDITIONS. MOISTRE IF(HED.GT.0.0)GO TO 17 MOISTRE ARE FUNCTIONS REFERENCED. PLACES STATEMENT THREE OF C - - - -- NOTE --FIRST MOISTRE K(1) =CONOUCT((TO(1) +TO(2))/2.) MOISTRE =0.0 IF( (TO(1) +TO(2) /2.).LE.TD)K(1) MOISTRE IF(ANT(1).LE.TO)D(1) =0.0 MOISTRE IF(ANT(1).GT. TO .AND. ANT( 1).LT.0.15)O(1) =DIFUSE1(ANT(1)) MOISTRE =DIFUSE2(ANT(1)) ANT( 1).LT.0.36)O(1) AND. IF(ANT(1).GE.0.15. MOISTRE IF(ANT(1).GE.0.36. AND. ANT( 1).LT.0.40)O(1) =DIFUSE3(ANT(1)) MOISTRE E(1) =1.0 MOISTRE IF(D(1).LE.0.0)54,55 MOISTRE F(1) =0.0 54 MOISTRE GO TO 18 MOISTRE F(1) =- K(1) *OELX /D(1) 55 20 CONTINUE DO 16 J =1,Q CONST= CONST +TN(J) CONST=CONST-0.5*(TN(1)+TN(Q)) X Page 53 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 GO TO 18 17 C TN(1)=TS NOTE--SECOND OF THREE PLACES STATEMENT FUNCTIONS ARE REFERENCED. K(1)=CONDUCT((TO(1)+TO(2))/2.) 0(1)=OIFUSE3(ANT(1)) c(1)=0.0 F(1)=TS COMPUTE C 18 35 C C C E ANO F FOR EACH NODE(J) FROM SURFACE TO DRAIN. N=1 P1=2 P2=HOR(N)/DELX+1 DO 5 J=P1,P2 COMPUTE SINK TERM FROM VALUE RETURNED FROM SUBROUTINE CONUSE. S(J)=U(J)*OELT/DELX IF(J.EQ.Q)GO TO 5 NOTE--THIRD OF THREE PLACES STATEMENT FUNCTIONS ARE REFERENCED. K(J)=CONOUCT((TO(J)+TO(J+1))/2.) IF((TO(J)+TO(J+1))/2.0.LE.TO)K(J)=0.0 IF(ANT(J).LE.T0)D(J)=0.0 IF(ANT(J).GT. TD .AND.ANT(J).LT.0.15)O(J)=DIFUSE1(ANT(J)) IF(ANT(J).GE.0.15.AND.ANT(J).LT.0.36)D(J)=DIFUSE2(ANT(J)) IF(ANT(J).GE.0.36.AND.ANT(J).LT.0.40)0(J)=DIFUSE3(ANT(J)) A=(OELT*0(J))/(2.*OELX**2) C=(OELT*D(J-1))/(2.*DELX**2) 8=1.+A+C W=A*TD(J+1)+(1.-A-C)*TO(J)+C*TO(J-1)+(K(J-1)-K(J)l*2.*G* 1DELT/(2.*DELX**2) EXTRACTION OF SINK TERM. IF(TO(J)-S(J).GT.TD)G0 TO 75 S(J)=T0(J)-TD W=W-S(J) Z(J)=Z(J)+(U(J)*OELT-S(J)*DELX) GO TO 76 75 76 5 W=W-S(J) ET=ET+S(J)*DELX E(J)=A/(B-C*E(J-1)) F(J)=(W+C*F(J-1))/(B-C*E(J-1)) CONTINUE IF(N.GE.0)GO TO 8 N=N+1 P1=P2+1 P2=HOR(N)/DELX+1 GO TO 35 C 8 48 COMPUTE THETA AND FLUX FOR EACH NODE(J) FROM DRAIN TO SURFACE. J=Q TN(Q)=BBC J=Q-1 TN(J)=E(J)*TN(J+i)+F(J) ANT(J)=(Y*(TN(J+1)-TO(J+1))+Y*(TN(J)-TO(J))+TN(J+1)+TN(J))/2. IF(ANT(J).GT.TS)ANT(J)=TS IF(ANT(J).LT.TD)ANT(J)=TD FN(J)=(K(J)-(D(J)*(TN(J+1)+TO(J+1)-TN(J)-TO(J))/(2.*DELX)))*DELT FR=FN(J)/DELT FR=ABS(FR) IR=AMAX1(IR,FR) SF(J)=SF(J)+FN(J) J=J-1 IF(J.GT.0)GO TO 48 CL=CL+FN(Q-1) ETS=ETS+FN(1) IF(FN(1).1E.0.0)GO TO 23 CI=CI+FN(1) HEO=HED-FN(1) IF(HEO.LE.0.0)HED=0.0 Page 54 MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTR£ MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE MOISTRE 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 23 C 6 C 2 C 19 C C 52 32 99 C 10 9 24 MOISTRE MOISTRE MOISTRE WRITE ON TAPE 5 OR PRINT THETA AND FLUX AT 0.1 DAY INTERVALS. IF(X.LT.0.1)G0 TO 2 MOISTRE WRITE( 5)( II, XT, J, TN( J), Z( J), SF(J),CI,CL,HED,ETS,U(J),J =1,Q) MOISTRE DO 6 J =1,Q MOISTRE Z(J) =0.0 MOISTRE SF(J) =0.0 MOISTRE MOISTRE CHECK TO SEE IF DAY II IS COMPLETED. MOISTRE IF(XT.LT.1.0)GO TO 34 MOISTRE MOISTRE COMPUTE -CHECK- AS MASS BALANCE CHECK ON LEACHATE. MOISTRE CONSTI=0.0 MOISTRE D0 19 J =1,Q MOISTRE MOISTRE CONST1=CONST1+TN(J) CONST1=CONSTI-0.5*(TN(1)+TN(Q)) MOISTRE DIF =( CONSTI- CONST) *DELX MOISTRE MOISTRE CHECK =ETSDIF -ET MOISTRE WRITE FINAL VALUES FOR LAST (I) IN DAY (II) AS INPUTS FOR DAY (II+ MOISTRE WRITE(4)(TN(J),FN(J),CL, CHECK, IR ,L,HED,ANT(J),CI,ETS,ET,J =1,Q) MOISTRE MOISTRE PRINT ONE OF TWO OPTIONS FOR DAILY OUTPUT. MOISTRE IF(BB.EQ.1)GO TO 52 MOISTRE PRINT 124 MOISTRE PRINT 103 MOISTRE PRINT 121,II,XT, MONTH ,IOTE,CL,CHECK,ETS,ET,DIF,I MOISTRE GO TO 32 MOISTRE PRINT 124 MOISTRE PRINT 103 MOISTRE PRINT 121,II,XT, MONTH ,IDTE,CL,CHECK,ETS,ET,OIF,I MOISTRE PRINT 105,(TN(J),J =1,0) MOISTRE MOISTRE CONTINUE MOISTRE STOP MOISTRE MOISTRE PRINT RUN PARAMETERS AND INITIAL CONDITIONS. MOISTRE IF(AA.EQ.1) 9,12 MOISTRE PRINT 109 MOISTRE PRINT 110 MOISTRE PRINT 122 MOISTRE PRINT 107 MOISTRE PRINT 111 ,AA,BB,CC,LL,MM,RBC,TBC,YEAR, CROP,M,APPS,DELX,TS,TM,TD, MOISTRE 1SM MOISTRE PRINT 119 MOISTRE PRINT 120,(TME(L),MON(L), DATE (L),At1T(L),ADENT(L),L =1,APPS) MOISTRE L =1 MOISTRE PRINT 113 MOISTR£ PRINT 114,(IDENT,HOR(N),N =1,O) MOISTRE PRINT 112 MOISTRE PRINT 105,(TH(J),J =1,0) MOISTRE PRINT 108 MOISTRE PRINT 115 MOISTRE PRINT 116 MOISTRE PRINT 117 MOISTRE IJKL =0 $ DO 24 IJK =1,12 IJKL =IJKL +1 MOISTRE PRINT 118,IJKL,MEANTI( IJK), P3( IJK),KA1(IJK),K81(IJK),UH(IJKL) MOISTRE IJKL =IJKL +1 MOISTRE PRINT 118,IJKL,MEANT2( IJK), P4( IJK),KA2(IJK),K82(IJK),UH(IJKL) MOISTR£ ICROP=1 $ PRINT 123,ICROP,( KP(IJK),IJK =1,6) MOISTRE ICROP=2 $ PRINT 123,ICROP,(KP1(IJK),IJK =1,6) MOISTRE ICROP =3 $ PRINT 123,ICROP,(KP3(IJK),IJK =1,6) MOISTRE PRINT 108 MOISTRE GO TO 12 MOISTRE MOISTRE CONTINUE Page 55 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 M OIST RE MOISTRE MOISTRE 100 MOISTRE 101 MOISTRE AMOUNT = *F7.2, DAY NUMBER *,I4, *. 102 MOISTRE 1* CM. MOISTRE CL IDTE XT MONTH 7X,* II 103 FORMAT( MOISTRE I*) OIF ET ETS CHECK 1 MOISTRE FORMAT(45X,F6.5) 104 MOISTRE FORMAT(10X,10F12.6) 105 MOISTRE FORMAT (20X,I2,1X,I2,5X,F10.0,39X,A1) 106 M AP MOIST RE MM BBC TBC YEAR CROP CC LL AA BB FORMAT( ,6X,* 107 MOISTRE TM TO SM *) TS 1PS DELX MOISTRE FORMAT(iHi) 108 FORMAT(1H1,3X, *PARAMETERS, CONSTANTS, AND INITIAL CONDITIONS USED MOISTRE 109 MOISTRE 1IN THIS REPORT. *) MOISTRE RELATIONS CONDUCTIVITY AND DIFFUSIVITY NOTE FORMAT( /,4X,* 110 MOISTRE !HIPS MUST BE INSERTED INTO SOURCE DECK.*, /) MOISTRE FORMAT(6X,5I5,2F5.2,4I5,5F5.2) 111 MOISTRE AT DEPT EACH THETA CONDITIONS. MOISTURE SOIL FORMAT( /,7X, *INITIAL 112 M O IST RE 1H NODE, READ ACROSS THEN DOWN. *) MOISTRE FORMAT( /,7X, *SOIL IDENTIFICATION AND HORIZON DEPTHS.*) 113 MOISTRE *,F5.1) DEPTH *. = *,AB, *IDENTIFICATION FORMAT(9X, 114 MOISTRE 115 FORMAT( /,7X, *CONSUMPTIVE USE DATA. *) MOISTRE BLANEY GRIDDLE DATA TO GET U FORMAT(9X, *SEMI MONTH 116 MOISTRE 1U IF CROP =3 ONLY. *) (CM/15 D MOISTRE KCROP PCT HV KCROP FORMAT(20X, *AVG TEMP 117 MOISTRE LAYS) *) MOISTRE FORMAT( 13X, I2, 7X, F4. 1, 6X ,F4.2,6X,F4.2,7X,F4.2,12X,F5.2) 118 MOISTRE FORMAT( /,7X, *WATER APPLICATION DAYS, DATES, AND AMOUNTS. *) 119 MOISTRE = *,F6.2,* *AMOUNT *,I2,7X, *,I2,*/ *DATE *,I4,7X, FORMAT(9X, *DAY NUMBER 120 MOISTRE SOURCE _ *,A1) 1 CM. MOISTRE 121 FORMAT (7X,I10,F10.3,2I10,5F10.4,I10) MOISTRE *) CONDITIONS. PARAMETERS, AND BOUNDARY FORMAT( /,7X, *RUN 122 MOISTRE FORMAT( /,9X, *PERCENT OF ROOTS IN EACH OF TOP 6 FEET. CROP = *,I1, 123 MOISTRE 16F9.3) F MOISTRE NODE IF AT EACH DEPTH THETA INCLUDING *DAILY /,2X, OUTPUT, FORMAT( 124 MOISTRE 1RINT OPTION B8 = 1. *) MOISTRE ENO CONUSE SUBROUTINE CONUSE(CROP,OELX,J,U) CONUSE THIS SUBROUTINE RETURNS CONSUMPTIVE USE (U) IN CM /DAY FOR EACH J C COMMON /XYZ /IOTE,MONTH,UH,KP3,KP, KPI ,MEANT1,MEANT2,P3,P4,KA1,KA2,KB CONUSE CONUSE 11,K82 CONUSE DIMENSION MEANT1( 12), MEANT2( 12), KA1 (12),KA2(12),K81(12),K82(12), CONUSE ),KP2(6,3),KP3(6),U1(24),UH(24) 6 1P3(12),P4(12),KP(6), KPI( CONUSE REAL MEANT1, MEANT2 ,KA1,KA2,KB1,KB2,KP,KP1,KP2,KP3 CONUSE INTEGER CROP CONUSE DATA(ICHECK=0) CONUSE CONUSE READ BLANEY GRIDDLE CONSUMPTIVE USE DATA C CONUSE DO 8 1 =1,12 CONUSE READ 102 ,MEANTI(I),P3(I),KA1(I),KB1(I) CONUSE READ 102 ,MEANT2(I),P4(I),KA2(I),K82(I) 8 CONUSE ROOT DISTRIBUTIONS TO GO WITH BLANEY GRIDDLE C CONUSE READ 100,( KP(I),I =1,6) CONUSE READ 100,(KP1(I),I =1,6) CONUSE CARDS FROM VALUES GO WITH CONUSE TO DISTRIBUTION C ROOT READ CONUSE READ 100,(KP3(I),I =1,6) CONUSE RETURN CONUSE CONUSE ENTRY CONUSEI CONUSE C COMPUTE DEPTH CONUSE 0 = DELX *(J 1.) C ONUSE CCONVERT DELX (CM) TO DELX (FT) CONUSE /30.5 DEL= DELX CONUSE C FORMAT STATEMENTS. FORMAT(5I5,2F5.0,4I5,5F5.0) FORMAT(I2,1A8,IF10.0) FORMAT( /,2X, *WATER APPLIEO. ) 1 READ Page 56 2 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 296 297 298 299 300 301 302 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 C C C 9 15 19 C 20 11 12 C C 1 2 C 3 C 4 C 5 C 6 C 7 C 100 101 102 READ U OFF DATA CARDS IF CROP =3 IF(CROP.NE.3)GO TO 11 IF SECOND SOIL DEPTH NODE, COMPUTE SUBSCRIPT FOR U1(ICOUNT) IF(J.NE.2)G0 TO 9 ICOUNT= MONTH *2 -0.5 CONVERT INCHES TO CM AND STORE CONUSE VALUES FOR PRINTING (UH) IF(IDTE.GE.16)ICOUNT= MONTH *2 +0.5 IF(ICHECK.E0.1)GO TO 20 ICHECK =1 DO 15 I =1,6 KP2(I,3) = KP3(I) DO 19 I =1,24 READ 101,0 U1(I) =U *2.54 UH(I) =U1(I) OBTAIN U FROM U1 MATRIX U=U1(ICOUNT) GO TO 7 DO 12 I =1,6 KP2(I,1) = KP(I) KP2(I,2) = KP1(I) I =MONTH BRANCH ACCORDING TO CROP GO TO (1,2),CROP BRANCH ACCORDING TO HALF OF MONTH IF(IOTE.LE.15)3,4 IF(IOTE.LE.15)5,6 COMPUTE CONSUMPTIVE USE FROM CONSUMPTIVE U =KA1(I) *(MEANT1(I) *P3(I)/100.) *2.54 COMPUTE CONSUMPTIVE USE FROM CONSUMPTIVE U= KA2(I) *(MEANT2(I) *P4(I)/100.) *2.54 COMPUTE CONSUMPTIVE USE FROM CONSUMPTIVE U =KB1(I) *(MEANT1(I) *P3(I)/100.) *2.54 COMPUTE CONSUMPTIVE USE FROM CONSUMPTIVE U= Kß2( I) *(MEANT2(I) *P4(I) /100.)+`2.54 USE FORMULA GO TO 7 i USE FORMULA $ GO TO 7 USE FORMULA $ GO TO 7 USE FORMULA REDUCE CONUSE TO A DAILY BASIS U=U /15. ADJUST CONUSE FOR SIZE OF DEPTH INTEERVALS AND ROOT DISTRIBUTION IF(D.LE.30.5) U = U *KP2(1,CROP) *DEL U= U *KP2(2,CROP) *DEL IF(O.GT.30.5.AND.D.LE.61.0) U=U *KP2(3,CROP) *OEL IF(D.GT.61.0.AND.O.LE.91.5) IF(0.GT.91.5.AND.D.LE.122.) U =U *KP2(4,CROP) *DEL U =U *KP2(5,CROP) *DEL IF(D.GT.122..AND.D.LE.153.) U =U *KP2(6,CROP) *DEL IF(D.GT.153..ANO.D.LE.183.) IF(D.GT.183) U =00 RETURN FORMAT(6F10.0) FORMAT(24X,F6.0) FORMAT(4F10.0) END SUBROUTINE THEDATE (K,L) COMMON /XYZ /IDTE,MONTH,UH,KP3 M =K +L GO TO 1 IF(M.GE.1.AND.M.LE.31) IF(M.GT.31.AND.M.LE.59) GO TO 2 GO TO 3 IF(M.GT.59.ANO.M.LE.90) IF(M.GT.90.AND.M.LE.120) GO TO 4 IF(M.GT.120.ANO.M.LE.151)GO IF(M.GT.151.ANO.M.LE.181)GO IF(M.GT.181.AND.M.LE.212)G0 IF(M.GT.212.AND.M.LE.243)G0 IF(M.GT.243.AND.M.LE.273)GO IF(M.GT.273.ANO.M.LE.304)GO IF(M.GT.304.AND.M.LE.334)G0 TO 5 TO 6 TO T TO 8 TO 9 TO 10 TO 11 Page 57 CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE CONUSE THEDATE THEDATE THEDATE THEOATE THEDATE THEDATE THEDATE THEOATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 2 3 4 5 6 7 8 9 10 11 12 1 2 3 4 5 6 7 8 9 10 11 12 IF(M.GT.334.ANO.M.LE.365)G0 TO 12 i MONTH= 1 IDTE =M $ MONTH= 2 IDTE =M 31 ñ MONTH= 3 IDTE =M 59 $ MONTH= 4 IDTE =M 90 $ MONTH= 5 IDTE =M 120 $ MONTH= 6 IDTE =M 151 $ MONTH= 7 IDTE =M 181 $ MONTH= 8 IDTE =M 212 $ MONTH= 9 IDTE =M 243 $ MONTH =10 IDTE =M 273 $ MONTH =11 IDTE =M 304 $ MONTH =12 IDTE =M 334 $ á $ $ $ $ $ $ $ $ $ RETURN RETURN RETURN RETURN RETURN RETURN RETURN RETURN RETURN RETURN RETURN RETURN END INTEGER FUNCTION DAY (K,L,M) GO TO (1,2,3,4,5,6,7,8,9,10,11,12) M $ RETURN OAY =K $ RETURN +31 OAY =K $ RETURN DAY =K +59 +90 $ RETURN DAY =K $ RETURN DAY =K +120 $ RETURN DAY =K +151 +181 $ RETURN DAY =K $ RETURN DAY =K +212 $ RETURN DAY =K +243 $ RETURN OAY =K +273 $ RETURN DAY =K +304 $ RETURN DAY =K -L +334 END PROGRAM INTFACE (INPUT,OUTPUT,TAPE1,TAPE5) DIMENSION TN( 60), Z( 60), SF( 60), U( 60 ),MOISIN(12),MOISOUT(11),SEGVOL 1(11) INTEGER AA,88,CC,Q REAL MOISIN,MOISOUT $ MOISIN(1) = 0.0 TEN _ 300. READ 100,AA,88,CC,Q,IPRINT DO 1 I =AA,BB READ (5) ( II, XT, K, TN( J), Z( J), SF(J),CI,CL,HEO,ETS,U(J),J =1,Q) K = 1 $ SEGVOL(1) = HED 00 4 M= 1,28,3 L L L L L L L L L L L K = 4 $ K + 1 SEGVOL(K) K = = 2.5 *TN(M) + 5.0 *TN(M +1) + 5.0*TN(M +2) + 2.5 *TN(M +3) 2 DO 5 M =4,28,3 K = 5 6 C C 1 100 105 K + 1 MOISIN(K) = (SF(M) + SF(M1)) /2. IF(SF(1).LT.0.0) SF(1) = 0.0 MOISIN(2) = SF(1) IF(MOISIN(2).GT.0.0) SEGVOL(1) = SEGVOL(1) + MOISIN(2) MOISIN(12) = SF(30) 00 6 J =2,12 MOISOUT(J 1) = MOISIN(J) IF(MOO(II,IPRINT).E0.0) PRINT 105, (II,M,M,SEGVOL(J),MOISIN(J), 1MOIS OUT(J),TEN,U(J),J =1,11) WRITE (1) (II,M,M,SEGVOL(J), MOISIN(J),MOISOUT(J),TEN,U(J),J =1,11) CONTINUE STOP FORMAT(525) FORMAT(5X,3I5,5E15.3) END Page 58 THEOATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE INTFACE 16 17 18 19 20 21 22 23 24 25 26 27 28 29 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 LISTINGS FOR BIOLOGICAL- CHEMICAL PROGRAM PROGRAM MAIN( INPUT, OUTPUT, TAPE1 = 1002 ,TAPE2 =1002,TAPE3 =1002,TAPE8 =1 MAIN MAIN 1002,TAPE9 =1002,TAPE10 =1002, PUNCH,TAPE15 =1002,TAPE4= INPUT) MAIN MAIN DIMENSION X(7,25) MAIN MAIN MAIN COMMON /ABLE/ TITLE( 10), SMONTH, MM, O, IPRINT,JPRINT,INK,IPUNCH,ISTOP, MAIN 1ITEST, IREADP, IMASS, IADD (25),IORNAP(5),HOR(9),TOTN(99), YEAR , MAIN 2AIRR( 9), IRR( 25), TT( 60), FERT( 7), OFERT (3),NORGIN,NFERTIN,NTEMPIN, MAIN 3ITOT,JTOT,IRTOT,NT MAIN COMMON /XX2 /A1,A2,A3,X MAIN COMMON /AFG /ENH3,II,LLL MAIN COMMON /YYY /START,IDTE,MONTH,I,LL MAIN COMMON /XXY/ ICHECK ,ICOUNT,CONV,PK,PKi,CROP,FACT MAIN COMMON /XXX /DELX,DELT,MS,WTART,B0(25 ),TEN(25 ),CHECK(25 ),MOISIN MAIN 1(25 ),CMH2O1(25 ),4OISOUT(25 ),AN03(25 ),ANH3(25 ),URE.A(25 ),ORN MAIN 2(25 ),CA(25 ),ANA(25 ),AMG(25 ),HCO3(25 ),CL(25 ),CO3(25 ),504(25 3),E5(25 ),C5(25 ),SA5(25 ),XX5(25 ),CASO(25 ),AGSO(25 ),BNH4(25 ), MAIN 4EC(25 ),CN1(25 ),SAMT(25 ),RN(25 ),RC(25 ),TEM(25 ),CAL(25 ),Q,SRO MAIN 25),CH,CH1,IRERUN,ISWCH,CUMSUM, MAIN 1P, XTRACT,SUMN03,THOR(4),TO,IDAY,U MAIN 1SUMOUT,REDUCE MAIN MAIN MAIN INTEGER Q, O, START,CROP,TO,SMONTH,YEAR,TITLE MAIN REAL MOISIN,MOISOUT MAIN MAIN DATA (CONV=11.221367) MAIN MAIN MAIN REWIND 3 $REWIND 8 SREWIND 9 $REWIND 10 MAIN MAIN C SET INITIAL VALUES MAIN ICHECK = 0 SCMH2O1(1) = 1.0 MAIN DO 693 I =1,7 MAIN DO 693 J =1,25 MAIN X(I,J) = 1.E +6 693 MAIN MAIN C - - -- READ TITLE CARD MAIN READ 88,TITLE MAIN MAIN C READ CONTROL CARDS MAIN READ 105,OELX, DELT, XTRACT, CH ,CH1,Ai,A2,REDUCE,PK,PKI,FACT, MAIN 1LL, MM, O, CROP, TO, NT, IPRINT, JPRINT, INK,IRERUN,IPUNCH,IREADP,ITEST, MAIN 2START,SMONTH, YEAR ,ISTOP,IMASS,IPRINTI,IPRINTJ MAIN MAIN C COMPUTE NO, OF TIME INTERVALS PER DAY MAIN LLL= 1. /DELT + 0.5 MAIN IF(IPRINTI.NE.0) CALL PRNT(IPRINTI,IPRINTJ) MAIN MAIN C READ TEMPERATURE HORIZON DEPTHS MAIN (THOR(J),J 107, =1,TO) READ MAIN MAIN C READ COMPONENT HORIZON DEPTHS MAIN READ 107,(HOR(J),J =1,0) MAIN MAIN MAIN C STORE TEMPERATURE PROFILE DATA ON TAPE 8 MAIN DO 800 J =1,NT MAIN READ 801,(TT(I),I =1,T0) MAIN WRITE(8) (TT(I),I =1,TO) MAIN 800 CONTINUE MAIN MAIN READ IRRIGATION WATER ANALYSIS C READ 100, ANH3(i),_ANO3(1),CA(1), ANA (1),AMG(1),HCO3(1),CL(1),CO3(1) MAIN ( Page 59 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 MAIN MAIN MAIN C- ----STORE TRANSFORMED IRRIGATION WATER ANALYSIS MAIN ORN(1)= UREA(1)= SAMT(1) =0.0 MAIN CALL UNITS1(1) SAIRR(3) =CA(1) $AIRR(4) =ANA(i) MAIN AIRR(1) =ANH3(1) $AIRR(2) =ANO3(1) AIRR(5)= AMG(1) $AIRR(8)= CO3(1) MAIN S(AIRR(6) =HCO3(1) $AIRR(7) =CL(1) MAIN AIRR(9)= SO4(1) MAIN C MAIN COMPUTE TOTAL NUMBER OF COMPONENT HORIZONS MAIN Q= HOR(0) /DELX +1.1 MAIN IF(ITEST.EQ.1)782,783 782 MAIN READ 784,(CMH2O1(J),MOISIN(J) ,MOISOUT(J),TEN(J),U(J),J =1,Q) MAIN MAIN PRINT HEADING C 783 MAIN IF(IRERUN.EQ.0) PRINT 201 MAIN MAIN C SET COUNTERS MAIN N =2 $L =1 $Ki = 1 MAIN MAIN C CALL OUTPT TO ZERO INITIAL VALUES MAIN CALL OUTPT(K1) MAIN IF(IRERUN.EQ.0)22,701 MAIN MAIN C READ INITIAL SOIL ANALYSES MAIN 22 READ 100,ANH3(1),AN03(1), UREA (1),CA(1),ANA(1),AMG(1),HCO3(1 MAIN 1),CL(1),CO3(1),504(1),EC(1), XX5 (1),CAL(1),B0(1),SAMT(1),CN1(1) MAIN PRINT INITIAL SOIL ANALYSES MAIN C MAIN PRINT 200,L,ANH3(1),ANO3(1), UREA( 1),SAMT(1),CA(1),ANA(1),AMG(1), MAIN 1HCO3(1),CL(1),CO3(1),SO4(1) MAIN MAIN C COMPUTE SEGMENT NUMBER OF COMPONENT HORIZON MAIN KK =HOR(L) /DELX +1.1 MAIN MAIN C STORE INITIAL SOIL ANALYSES IN PROPER COMPONENT ARRAYS MAIN DO 23 J =N,KK MAIN $UREA(J) =UREA(1) ANH3(J)= ANH3(1) $AN03(J) =AN03(1) MAIN CA(J) =CA(1) $ANA(J) =ANA(1) $AMG(J)= AMG(1) MAIN HCO3(J) =HCO3(1) $CL(J) =CL(1) $CO3(J) =CO3(1) MAIN SO4(J) =SO4(1) $EC(J) =EC(1) $XX5(J) =XX5(1) CAL(J) =CAL(1) MAIN $BD(J) =B0(1) $SAMT(J)= SAMT(1) MAIN CN1(J) =CN1(1) MAIN 23 CONTINUE MAIN MAIN MAIN C CHECK FOR LAST SEGMENT MAIN IF(KK.EO.Q)20,21 MAIN MAIN C RESET COUNTERS HAIN 21 N =KK +1 MAIN L =L+1 MAIN GO TO 22 MAIN PRINT HEADING MAIN C PRINT 202 MAIN 20 MAIN GO TO 703 701 MAIN CONTINUE MAIN FOR A RERUN, READ FROM TAPES OR FROM CAROS MAIN C MAIN IF(IREADP.EQ.0) (3) ICOUNT, NFERTIN, NORGIN, NTEMPIN ,(ANH3(J),ANO3(J),UREA(J) MAIN 1READ 1,CA(J), ANA( J), AMG( J), HCO3( J), CL( J), CO3(J),SO4(J),EC(J),XX5(J),CAL( MAIN 2J), BD( J), SAMT( J), CN1( J), ORN( J), RN( J ),RC(J),E5(J),C5(J),SA5(J),CASO MAIN MAIN 3(J),AGSO(J),BNH4(J),J =2,Q) IF(IREADP.NE.0) MAIN 1,SO4(1) Page 60 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 510 SPACE TAPER FOREWARD THE PROPER NO. DO 510 I =1,NTEMPIN READ (8) 522 IF(NFERTIN.EQ.0) GO TO 550 C 511 SPACE TAPE9 FOREWARD THE PROPER NO. OF RECORDS 00 511 I= 1,NFERTIN READ (9) 550 IF(NORGIN.EQ.0) GO TO 513 MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN C SPACE TAPE10 FOREWARD THE PROPER NO. OF RECORDS MAIN ICOUNT,NFERTIN,NORGIN, NTEMPIN ,(ANH3(J),AN03(J),UREA(J) 1READ 505, 1,CA(J), ANA( J), AMG( J), HCO3( J), CL( J), CO3(J),504(J),EC(J),XX5(J),CAL( 2J), BD( J), SAMT( J), CN1( J), ORN( J), RN( J ),RC(J),E5(J),C5(J),SA5(J),CASO 3(J),AGSO(J),BNH4(J),J =2,Q) C SET INITIAL VALUES 703 1 J =2,Q IF(IRERUN.EQ.0)780,781 ORN(J)= RC(J)= RN(J)= CHECK(J)=0.0 SA5(J)= BNH4(J) =0.0 CMH2O1(J) = XTRACT +BD(J)*DELX 780 DO EC(J) =EC(J) /1.E5 C C 781 CALL UNIT CONVERSION SUBROUTINE CALL UNITSI(J) PRINT TRANSFORMED DATA PRINT 200, J,ANH3(J),AN03(J), UREA( J),SAMT(J),CA(J),ANA(J),AMG(J), IHCO3(J),CL(J),CO3(J),504(J) IF(IRERUN.EQ.i) CHECK(J) =1.0 i CONTINUE C READ FERTILIZER APPLICATION OATES READ iO4,ITOT,(IADD(K),K =1,ITOT) C READ ORGANIC -N APPLICATION DATES READ 106,JTOT,(IORNAP(K),K =1,JTOT) C- READ IRRIGATION WATER APPLICATION DATES READ 104,IRTOT, (IRR(K),K =1,IRTOT) C STORE FERTILIZER APPLICATIONS ON TAPE 00 802 I =1,ITOT READ 100,(FERT(J),J =1,7) WRITE(9) (FERT(J),J =1,7) CONTINUE 802 C 803 C 16 508 C 9 STORE ORGANIC APPLICATIONS ON TAPE 10 00 803 I =1,JTOT READ 100,(OFERT(J),J =1,3) WRITE(10) (OFERT(J)- ,J=1,3) CONTINUE SET SEGMENT ONE VALUES EQUAL TO ZERO ANH3(1) =ÁN03(1) =CÁ(1)= ANA( 1)= AMG( 1 ) =HCO3(1) =UREA(1) =CL(1) =CO3(1)= 1504(1) =0.0 IF(IRERUN.NE.0)508,720 REWIND 8 REWIND 9 REWIND 10 IF(NTEMPIN.EQ.0) GO TO 522 OF RECORDS MAIN Page 61 132 133 134 135 136 i37 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 512 00 512 I= 1,NORGIN READ (10) GO TO 513 720 513 C C 726 REWIND 8 REWIND 9 REWIND 10 NFERTIN = NORGIN = NTEMPIN = 0 CONTINUE ISWCH = 1 IF(IPRINTJ.NE.0) CALL PRNT1(IPRINTI,IPRINTJ) CALL SUBROUTINE TO EXECUTE PROGRAM FOR EACH DAILY TIME INTERVAL CALL EXECUTE CHECK FOR ENO OF RUN IF(MOD(IDAY,365).EQ.0)726,721 IF(YEAR.EQ.ISTOP) GO TO 721 C---- -RESET COUNTERS ICOUNT = 0 $YEAR = YEAR + 1 ILL = 1 GO TO 720 721 C 502 ENOFILE 2 ENDFILE 15 NTEMPIN =NTEMPIN -1 ICOUNT =-ICOUNT -1 EITHER PUNCH A RERUN DECK OR WRITE RERUN (RESTART) DATA ON TAPE3 IF(IDAY.EQ.365) ICOUNT = NFERTIN = NORGIN = NTEMPIN = 0 IF(IPUNCH.EQ.0) 502,503 REWIND 3 (3) ICOUNT,NFERTIN,NORGIN, NTEMPIN ,(ANH3(0,AN03(J),UREA(J) WRITE 1,CA(J), ANA( J), AMG( J), HCO3( J), CL( J), CO3(J),SO4(J),EC(J),XXS(J),CAL( 2J),BD(J), SAMT( J), CNI( J), ORN( J), RN( J ),RC(J),E5(J),C5(J),SA5(J),CASO 3(J),AGSO(J),BNH4(J),J =2,Q) GO TO 561 503 561 88 100 104 105 106 107 200 201 202 505 784 801 C PUNCH 505, ICOUNT,NFERTIN,NORGIN, NTEMPIN ,(ANH3(J),ANO3(J),UREA(J) 1,CA(J), ANA( J), AMG( J), HCO3( J), CL( J), CO3(J),SO4(J),EC(J),XX5(J),CAL( 2J),BD(J), SAMT( J), CN1( J), ORN( J), RN( J ),RC(J),E5(J),C5(J),SA5(J),CASO 3(J),AGSO(J),BNH4(J),J =2,Q) REWIND 2 REWIND 3 STOP FORMAT(10A8) FORMAT(16F5.0) FORMAT (16I5) FORMAT(11F5.0 /16I5/4I5) FORMAT(11I5) FORMAT(5F5.0) FORMAT(I5,11F10.3) FORMATE / / / /1X *INITIAL SOIL ANALYSES(MEQ /L OF SOIL EXTRACT)- -(ORG= lUG /GM OF SOIL)* / /2X *HZN* *HCO3 *8X *CL 7X*NH3 *7X *NO3 *6X* UREA *7X *ORG*8X*CA*8X *NA*8X *MG *6X 1 1 *7X *CO3 *7X *SO4*) FORMAT( / /1X *TRANSFORMED SOIL ANALYSES(UG /SEGMENT OF SOIL) * / /2X*SEG *HCO3 *8X *CL 7X *NH3 *7X *NO3 *6X* UREA *7X *ORG *8X *CA *8X *NA *8X *MG *6X 1* 1 *7X *CO3 *7X *SO4*) FORMAI(4I5 /,(6Eí3 .5 /6E13.5/6E13.5/6E13.5/E13.5)) FORMAT(5F10.0) FORMAT(2X,F8.0,7F10.0) END SUBROUTINE EXECUTE SUBROUTINE TO EXECUTE PROGRAM FOR EACH DAILY TIME INTERVAL Page 62 MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN HAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN MAIN EXECUTE EXECUTE EXECUTE 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 2 3 4 COMMON/ ABLE/ TITLE( 10), SMONTH, MM, O, IPRINT,JPRINT,INK,IPUNCH,ISTOP, , 1ITEST, IREAOP, IMASS, IADD (25),IORNAP(5),HOR(9),TOTN(99), YEAR 2AIRR(9),IRR(25),TT(60), FERT(7), OFERT (3),NORGIN,NFERTIN,NTEMPIN, 31T0T,JTOT,IRTOT COMMON /XX2 /A1,A2,A3,X COMMON /YYY /START,IDTE,MONTH,I,LL COMMON/ XXY /ICHECK,ICOUNT,CONV,PK,PKI,CROP COMMON /AFG /ENH3,II,LLL COMMON /XXX /DLX,DELT,MS,WTART,8O(25 ),TEN(25 ),CHECK(25 ),MOISIN 1(25 ),CMH2O1(25 ),MOISOUT(25 ),ANO3(25 ),ANH3(25 ),UREA(25 ),ORN 2(25 ),CÁ(25 ),ANA(25 ),AMG(25 ),HCO3(25 ),CL(25 ),CO3(25 ),SO4(25 3),E5(25 ),C5(25 ),SA5(25 ),XX5(25 ),CASO(25 ),AGSO(25 ),BNH4(25 ), 4EC(25 ),CN1(25 ),SAMT(25 ),RN(25 ),RC(25 ),TEM(25 ),CAL(25 ),Q,SRO 25),CH,CH1,IRERUN,ISWCH,CUMSUM, 1P, XTRACT ,SUMNO3,THOR(+4),TO,IDAY,U 1SUMOUT ( EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE FXECUTE "CUTE DIMENSION X(7,25) INTEGER Q,O,START,CROP,TO,SMONTH,YEAR REAL MOISIN,MOISOUT C C G C 3 C 301 C 600 606 601 602 CUTE ¿CUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE LL = STARTING DAY, MM = TERMINATION DAY EXECUTE 00 4 I = LL,MM EXECUTE IF(MOD(I,IMASS).EQ.0) ISWCH = 1 EXECUTE EXECUTE STORE DAILY INTERNAL VALUES ON TAPE15 EXECUTE WRITE (15) ANH3(J),ANO3(J), UREA( J), CA (J),ANA(J),AMG(J),HCO3(J),CL(J EXECUTE 1(I,J, EXECUTE 1),CO3(J),SO4(J),EC(J),XX5(J), CAL( J),BD(J),SAMT(J),CN1(J),ORN(J), EXECUTE 2RN(J),RC(J),E5(J),C5(J), SAS( J) ,CASO(J),AGSO(J),BNH4(J),J =1,0) EXECUTE IF(I.E(1.1) REWIND 1 EXECUTE EXECUTE CALL SUBROUTINE TO COMPUTE DAY OF MONTH EXECUTE CALL THEDATE(START,I,SMONTH,O) EXECUTE IDAY = I EXECUTE EXECUTE CHECK FOR FERTILIZER APPLICATION DATE EXECUTE DO 3 K =1,ITOT EXECUTE IF(I.EQ.IADD(K))301,3 EXECUTE CONTINUE EXECUTE GO TO 5 EXECUTE EXECUTE READ FERTILIZER APPLICATIONS FROM TAPE 9 EXECUTE READ(9) DEPTH, AANH3,AANO3,AUREA,ACA,ASO4,ACO3 EXECUTE NFERTIN = NFERTIN + 1 EXECUTE EXECUTE IF SURFACE APPLICATION, BRANCH TO 600. OTHERWISE GO TO 601 EXECUTE IF(DEPTH.EQ.0.)6O0,601 EXECUTE CCC = CONV EXECUTE IS = 1 $IDEPTH = 1 EXECUTE GO TO 602 EXECUTE IDEPTH = DEPTH /DELX + 1 EXECUTE IF(IDEPTH.LT.2) IDEPTH = 2 EXECUTE IS = 2 EXECUTE CCC = DELX /DEPTH *CONV EXECUTE SAVEI = AANH3 *CCC +0.7777 EXECUTE SAVE2 = AANO3 *CCC *0.2258 EXECUTE SAVE3 = AUREA *CCC *0.4466 EXECUTE SAVE4 =ACA *CCC EXECUTE SAVE9 =ACO3*CCC EXECUTE SAVE10 =ASO4 *CCC EXECUTE EXECUTE DO 302 J = IS,IOEPTH EXECUTE Page 63 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 C C 302 5 C 7 C C C C 303 8 C 17 C 580 581 C C C C C 400 402 C EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE STORE ACCUM AMOUNTS OF FERTILIZER ADDED EXECUTE + + + SAVE3 SAVE2 SAVE1 CUMSUM = CUMSUM EXECUTE CUMCA =CUMCA +SAVE4 EXECUTE CUMC03= CUMCO3 +SAVE9 EXECUTE +SAVE10 CUMSO4= CUMSO4 EXECUTE DO 8 K= 1,JTOT EXECUTE EXECUTE DATE APPLICATION ORGANIC -N FOR CHECK EXECUTE IF(I.EQ.IORNAP(K))7,8 EXECUTE CONTINUE EXECUTE EXECUTE READ ORGANIC -N APPLICATION EXECUTE READ (10) DEPTH,ACNI,SSAMT EXECUTE NORGIN = NORGIN + 1 EXECUTE EXECUTE VALUES ANO STORE TRANSFORM EXECUTE IDEPTH = DEPTHIDELX + 1 EXECUTE IF(IDEPTH.LT.2) IOEPTH = 2 EXECUTE DELXIDEPTH*CONV CCC = EXECUTE EXECUTE DO 303 J =2,IDEPTH EXECUTE EXECUTE STORE ORGANIC -N APPLICATION INTO PROPER ARRAYS EXECUTE + +CCC SSAMT SAMT(J) = SAMT(J) EXECUTE EXECUTE STORE ACCUM AMOUNT OF ORGANIC -N ADDED EXECUTE SAVE = SSAMT+`CCC30.41ACN1 EXECUTE CUMSUM = CUMSUM + SAVE EXECUTE CN1(J) = ACN1 EXECUTE GO TO 17 EXECUTE CONTINUE EXECUTE EXECUTE COMPUTE TEMPERATURE READ -IN DATE EXECUTE IF( MOO( I ,7).EQ.O.OR.ICHECK.EQ.0)580,581 EXECUTE EXECUTE CALL TEMPERATURE INPUT SUBROUTINE EXECUTE CALL TEMP iNTEMPIN = NTEMPIN + 1 EXECUTE CONTINUE EXECUTE IF(MOD(I,INK).EQ.0) K = 2 EXECUTE EXECUTE INTERVAL TIME FOR PROGRAM EACH ENTER LOOP TO EXECUTE EXECUTE EXECUTE PER DAY HERE ILL IS THE NO. OF TIME INTERVALS EXECUTE EXECUTE THE PROGRAM MAY OR MAY NOT CALL ALL OF THE COMPUTATIONAL SUBEXECUTE ROUTINES FOR EACH INTERVAL EXECUTE EXECUTE EXECUTE PER DAY ONCE LEAST AT ARE CALLED ALL CRITICAL ROUTINES EXECUTE EXECUTE DO 10 II =1,LLL EXECUTE ).EQ.O.ANO.II.EQ.JPRINT)400,401 MOD( IDAY, IPRINT IF( EXECUTE PRINT 206.1.11 EXECUTE PRINT 205 EXECUTE CONTINUE EXECUTE EXECUTE PROGRAM FLOW FROM MOISTURE READ INPUT DATA ON TAPEI IF(ITEST.EQ.0) READ( 1)( I1, I2, I3, CMH2O1 (J),MOISIN(J),MOISOUT(J),T£N EXECUTE ADD THE FERTILIZER TO THE PROPER ARRAYS ANH3(J) = ANH3(J) + SAVE1 AN03(J) = AN03(J) + SAVE2 UREA(J) = UREA(J) + SAVE3 CA(J) =CA(J) +SAVE4 CO3(J)= CO3(J) +SAVE9 SO4(J)= SO4(J) +SAVE10 Page 64 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 1(J),U(J),J=1,Q) IF(II.E0.1.AND.CMH2O1(1).GT.0.0)790,795 C 790 C 793 C CHECK TO SEE IF THIS IS AN IRRIGATION DAY 00 792 18 = 1,IRTOT IF(I.EQ.IRR(L8))793,792 ENTER ROUTINE TO ADO IRRIGATION WATER COMPONENTS SSAVE2=AIRR(2)*CMH2O1(1) SAVE1=AIRR(1)*CMH2O1(1) $SAVE5=AIRR(4)*CMH2O1(1) SAVE4=AIRR(3)*CMH2O1(1) $SAVE7=AIRR(6)*CMH2O1(1) SAVE6=AIRR(5)*CMH2O1(1) $SAVE9=AIRR(8)*CMH2O1(1) SAVE8=AIRR(7)*CMH2O1(1) SAVE10=AIRR(9)*CMH2O1(1) áAN03(i)=AN03(1)+SAVE2 ANH3(1)=ANH3(1)+SAVE1 $ANA(1)=ANA(1)+SAVE5 CA(1)=CA(1)+SAVE4 $HCO3(1)=HCO3(1)+SAVE7 AMG(1)=AMG(1)+SAVE6 $CO3(1)=CO3(1)+SAVE9 CL(1)=CL(1)+SAVE8 SO4(1)=SO4(1)+SAVEID STORE ACCUM AMOUNTS OF COMPONENTS SCUMCA=CUMCA+SAVE4 CUMSUM=CUMSUM+SAVEI+SAVE2 $CUMAMG=CUMAMG+SAVE6 CUMANA=CUMANA+SAVE5 áCUMCL=CUMCL+SAVE8 CUMHCO3=CUMHCO3+SAVE7 ñCUMSO4=CUMSO4+SAVE10 CUMC03=CUMC03+SAVE9 GO TO 795 792 795 CONTINUE CONTINUE C CALL COMBINE SUBROUTINE CALL COMBINE(IDAY,IPRINT,JPRINT) CONTINUE CONTINUE RETURN 10 4 205 206 FORMAT( 1X *PREDICTED AMOUNTS(UG /SEGMENT OF SOIL) -- (SEGVOL =CC NATE 1R/SEG SOIL)* / /2X*SEG* *HCO3 *8X *CL 7X *NH3 *7X *NO3 *6X* UREA *7X *ORN *8X *CA *8X *NA *8X *MG *6X 1 1 *7X *CO3 *7X *SO4* 6X *ENH4 *4X *SEGVOL *) FORMAT( / /IX*OAY= *,I4,10X *TIME INTERVAL= *,I4) ENO SUBROUTINE COMBINE(IDAY,IPRINT,JPRINT) C C THIS SUBROUTINE CALLS THE COMPUTATIONAL SUBROUTINES AND ASSEMBLES THEIR DELTA VALUES COMMON /SABLE /SUMS(3) COMMON /EEE /PSUM,DIFNH4,0IFN03,TPLANT COMMON /XXY/ICHECK,ICOUNT COMMON /YYY /START,IDTE,MONTH,III,LL COMMON /AFG /ENH3,II,LLL COMMON /XXX /OELX,DELT,MM,WTART,BD(25 ),TEN(25 ),CHECK(25 ),MOISIN 1(25 ),CMH2O1(25 ),MOISOUT(25 ),AN03(25 ),ANH3(25 ),UREA(25 ),ORN 2(25 ),CA(25 ),ANA(25 ),AMG(25 ),HCO3(25 ),CL(25 ),CO3(25 ),SO4(25 3),E5(25 ),C5(25 ),SA5(25 ),XX5(25 ),CASO(25 ),AGSO(25 ),BNH4(25 ), 4EC(25 ),CN1(25 ),SAMT(25 ),RN(25 ),RC(25 ),TEM(25 ),CAL(25 ),Q,CRO 1P, SPACE (36),ISWCH,CUMSUM,SUMOUT,REDUCE COMMON / GIRL/ UREAI, UREA2, DNH31, 0NH32 ,DN031,0N032,CA1,ANAI,AMG1, 1HC031,CL1,C031,S041,KKK DIMENSION CONVERT( 25), EXNH3( 25 ),EXCA(25),EXANA(25),EXAMG(25), 1OELN03( 25), DELNH3( 25), DELORGN( 25), DELUREA (25),EXHCO3(25),EXC03(25) 2, EXSO4( 25), EXCL( 25), EXBNH4( 25), FLN03 (25),FLNH3(25),FLUREA(25),FLCA 3( 25), FLANA( 25), FLAMG( 25), FLHCO3( 25 ),FLCL(25),FLC03(25),FLSO4(25), 4PLN03( 25), PLNH4( 25), DELBNH4( 25), ANETI (25),ANET2(25),ANET3(25),ADOI 5T( 25) ,ADDITI(25),OELRN(25),DELRC(25) Page 65 EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE EXECUTE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 COMBINE COMBINE COMBINE IFACT = REDUCE COMBINE ISET = IFACT + 2 4F = 1.0 COMBINE IF(II.EQ.LLL) K =2 COMBINE COMBINE C COMPUTE DELTA VALUES FOR EACH SOIL SEGMENT COMBINE DO 1 I =2,Q 50 COMBINE COMBINE CALL SHUT -OFF SUBROUTINE C CALL CHK(L1,L2,13,I,EXNH3(I), EXCA( I),EXANA(I),EXAMG(I),DELN03(I), COMBINE COMBINE 10ELNH3 (I),OELORGN(I),DELUREA(I)) COMBINE IF(II.EQ.1.OR.ISET.LE.IFACT)3,4 COMBINE 3 L1 =L2 =L3 =0 COMBINE 4 CONTINUE COMBINE COMBINE C SET A UNIT CONVERSION CONSTANT COMBINE CONVERT(I) = OELX *BD(I) COMBINE COMBINE C CALL THE EXCHANGE SUBROUTINE IF(L1.E(A.0) CALL XCHANGE(I, EXNH3( I) ,EXCA(I),EXANA(I),EXAMG(I),EXHC COMBINE COMBINE 103( I), EXCO3 (I),EXS04(I),EXCL(I),EXBNH4(I)) IF(L1.NE.0) EXNH3( I)= EXCA( I) = EXANA( I) = EXAMG(I) =EXHCO3(I) =EXC03(I) = COMBINE COMBINE 1EXSO4(I)= EXBNH4(I)= EXCL(I) =0.0 COMBINE COMBINE C CALL THE NITROGEN TRANSFORMATION SUBROUTINE IF(L2.EQ.0) CALL TRNSFM(I, CONVERT( I ),DELUREA(I),DELORGN(I),DELNH3( COMBINE COMBINE 1I), DELN03( I), DELBNH4 (I),DELRN(I),DELRC(I),II) COMBINE COMBINE C CALL THE FLOW SUBROUTINE CALL FL( I, FLN03( I), FLNH3 (I),FLUREA(I),FLCA(I),FLANA(I) COMBINE COMBINE 1, FLAMG( I), FLHCO3 (I),FLCL(I),FLC03(I),FLSO4(I)) COMBINE IF(II.NE.1) GO TO 20 COMBINE IF(ISET.LE.IFACT) GO TO 20 COMBINE COMBINE C CALL THE PLANT NUTRIENT UPTAKE SUBROUTINE COMBINE IF( IDTE. EQ .1.OR.IDTE.EQ.15.OR.IDAY.EQ.LL) CALL UPTAKE(I,PLNO3(I), COMBINE 1PLNH4(I),DELT,OELX) COMBINE 20 CONTINUE COMBINE COMBINE C TEST FOR NEGATIVE RATE AND ZERO MASS COMBINE IF( DELNH3( I). LT.0.0.AND.ANH3(I).EQ.0.0)60,61 60 COMBINE DELBNH4(I) = DELBNH4(I) + DELNH3(I) /14.0E6 COMBINE DELNH3(I) = 0.0 COMBINE 61 CON = AN03(I) /CMH2O1(I) COMBINE CON/ = ANH3(I) /CMH2O1(I) COMBINE COMBINE C TEST FOR LOW NO3 CONCENTRATION COMBINE IF(CON.LT.O.2)62,63 COMBINE 62 ADDIT(I) = 0.0 COMBINE GO TO 64 COMBINE 63 ADDIT(I) = PLN03(I) COMBINE COMBINE C--- --TEST FOR LOW NH4 CONCENTRATION COMBINE 64 IF(CONI.LT.0.2)65,66 COMBINE 65 ADDITI(I) = 0.0 COMBINE GO TO 67 COMBINE 66 ADDIT /(I) = PLNH4(I) COMBINE 67 CONTINUE COMBINE COMBINE C COMPUTE NET CHANGES FOR NH4, UREA, AND NO3 COMBINE ANETI(I) = OELNH3(I) + FLNH3(I) + EXNH3(I) + ADDITI(I) COMBINE ANET2(I)= DELUREA(I) + FLUREA(I) COMBINE ANET3(I)= OELN03(I) + FLN03(I) + ADOIT(I) COMBINE COMBINE -TEST TO DETERMINE IF SEGMENT ONE IS BEING CONSIDERED INTEGER Q C- Page 66 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 77 1 IF(KKK.EQ.1)77,1 SNH31 =DNH31 $SNO31 =0N031 $SREA1 =UREA1 $SA1 =CAt $SNA1 =ANA1 SMGI =AMG1 $SC031 =HC031 SSLI =CL1 $5031 =C031 $R041 =SO41 CONTINUE C TEST TO DETERMINE IF ADDITIONAL TIME STEPS ARE BEING USED IF(ISET.LE.IFACT) GO TO 16 C TEST TO DETERMINE IF MASS IN SYSTEM WILL BE EXCEEDED 00 5 I =2,Q IF(ANH3(I) + ANET1(I).LT.0.0) GO TO 14 IF(UREA(I) + ANET2(I).LT.0.0) GO TO 14 IF(ANO3(I) + ANET3(I).LT.0.0) GO TO 14 5 CONTINUE GO TO 16 C 14 C 16 USE SMALLER TIME STEPS IF NECESSARY $F = IFACT ISET = 1 UPDATE THE MASSES DO 6 I =2,Q ANH3(I) = ANH3(I) AN03(I) = AN03(I) IN STORAGE + + ANET1(I) /F ANET3(I) /F $UREA(I) = UREA(I) + ANET2(I) /F SCA(I) = CA(I) + FICA(I) /F + EXCA( 1I) ANA(I) = ANA(I) + FLANA(I) /F + EXANA(I) $ AMG(I) = AMG(I) + FLAMG(I /F +EXAMG(I) HCO3(I) = HCO3(I) + FLHCO3(I) /F + EXHCO3(I) SCL(I) = CL(I) + FLCL 1(I) /F + EXCL(I) $SO4(I) = SO4(I) + FLSO4( CO3(I) = CO3(I) + FLC03(I) /F + EXC03(I) 1I) /F + EXSO4(I) BNH4(I) = BNH4(I) + EXBNH4(I) + OELBNH4(I) /F %ORN(I) =ORN(I) +DELORG IN(I) /F $RN(I) =RN(I) +DELRN(I) /F SRC(I) =RC(I) +DELRC(I) /F IF(I.EQ.Q) 30,31 1) C 30 C 31 36 37 KEEP TRACK OF TOTAL -N LEACHED FROM SYSTEM SUMOUT = SUMOUT +(0N032 + DNH32 + UREA2) /F SUMS(1) = SUMS(1) + DN032 /F SUMS(2) = SUMS(2) + DNH32 /F SUMS(3) = SUMS(3) + UREA2 /F UPDATE MASSES CONTAINED ON SOIL SURFACE IF(I.E(1.2)36,37 ANH3(1) = ANH3(1) - SNH31 /F$AN03(1) = AN03(1) - SNO31 /F UREA(I) = UREA(1) - SREA1 /F$CA(1) = CA(1) - SAi /F ANA(i) = ANA(1) - SNA1 /F$AMG(1) = AMG(1) - SMG1 /F HCO3(1) = HCO3(1) - SC031 /F $CL(1) = CL(i) - SL1 /F CO3(1) = CO3(1) - S031/F$SO4(1) = SO4(i) - R041/F CONTINUE C CHECK AND CORRECT FOR ANY NEGATIVE VALUES IF(BNH4(I).LT.0.0) BNH4(I) = 0.0 IF(AN03(I).LT.0.0) AN03(I) = 0.0 IF(ANH3(I).LT.0.0) ANH3(I) = 0.0 IF(UREA(I).LT.0.0) UREA(I) = 0.0 IF(ORN(I).LT.0.0) ORN(I) = 0.0 IF(CA(I).LT.0.0) CA(I) = 0.0 IF(ANA(I).LT.0.0) ANA(I) = 0.0 IF(AMG(I).LT.0.0) AMG(I) = 0.0 IF(HCO3(I).LT.0.0) HCO3(I) = 0.0 IF(CL(I).LT.0.0) CL(I) = 0.0 IF(CO3(I).LT.0.0) CO3(I) = 0.0 IF(SO4(I).LT.0.0) SO4(I) = 0.0 C KEEP TRACT OF PLANT UPTAKE OF N Page 67 COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE COMBINE 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 17 18 25 C C 2 6 C C C 100 C C C C C C COMBINE COMBINE COMBINE COMBINE L1 =L2 =L3 =0 COMBINE GO TO 25 COMBINE $PL2 = ADDITI(I) PLi = ADDIT(I) COMBINE TPLANT = TPLANT + PLNH4(I) + PLN03(I) COMBINE PSUM = PSUM + PL1 + PL2 COMBINE IF(ANH3(I).EQ.0.0) DIFNH4 = DIFNH4 + PL2 COMBINE IF(AN03(I).EQ.0.0) DIFNO3 = DIFNO3 + PL1 COMBINE IF(ISET.LT.IFACT) GO TO 6 COMBINE IF(MOD(IOAY,IPRINT).E Q.O.AND.II.EQ.JPRINT)2,6 COMBINE COMBINE PRINT VALUES FOR THE COMPONENTS (UG /SEGMENT) ANO SEGMENT VOLUMES COMBINE (ML) COMBINE VNH3 = BNH4(I)}14.0E6 *CONVERT(I) COMBINE PRINT 100,I,ANH3(I),AN03(I), UREA (I),ORN(I),CA(I),ANA(I),AMG(I), COMBINE IHCO3( I), CL( I),CO3(I),504(I),VNH3,CMH2O1(I) COMBINE CONTINUE COMBINE ISET = ISET + 1 COMBINE IF(ISET.LE.IFACT) GO TO 50 COMBINE COMBINE CALL SUBROUTINE TO OUTPUT LEACHATE VALUES COMBINE CALL OUTPT(K) COMBINE COMBINE CALL MASS BALANCE ROUTINE FOR NITROGEN COMBINE IF(ISWCH.EQ.1.AND.II.EQ.JPRINT) CALL MCHECK COMBINE COMBINE COMBINE RETURN TO SUBROUTINE EXECUTE COMBINE RETURN COMBINE COMBINE FORMAT(I5,13F1Q.3) COMBINE COMBINE END SUBROUTINE TRNSFM(J1, CONVERT, OELUREA ,DELORGN,DELNH3,DELNO3,OELBNH4 TRNSFM TRNSFM 1,DELRN,DELRC,II) TRNSFM TRNSFM THIS IS THE NITROGEN TRANSFORMATION SUBROUTINE TRNSFM TRNSFM TRNSFM COMMON /AFG /ENH3,II1,LLL TRNSFM COMMON /XXX /DELX,DELT,MM,START,BO(25 ),TEN(25 ),CHECK(25 ),MOISIN TRNSFM 1(25 ),CMH2O1(25 ),MOISOUT(25 ),ANO3(25 ),ANH3(25 ),UREA(25 ),ORN 2(25 ),CA(25 ),ANA(25 ),AMG(25 ),HCO3(25 ),CL(25 ),CO3(25 ),504(25 TRNSFM 3),E5(25 ),C5(25 ),SÁ5(25 ),XX5(25 ),CASO(25 ),AGSO(25 ),BNH4(25 ), TRNSFM 4EC(25 ),CNR(25 ),AOR (25 ),RN(25 ),RC(25 ),TEM(25 ),CS (25 ),Q,CRO TRNSFM TRNSFM 1P, XTRACT, SUMNO3, THOR( 4),TO,IOAY,U3(25),CH,CH1,IRERUN TRNSFM TRNSFM INTEGER CROP,TO,Q TRNSFM DIMENSION AMT (130,4),R(130,5),C(5),B1(5),T( 1 ),82(5),A(5),W( 1), TRNSFM TRNSFM 1B3(5),SAMT(2,4),CN1(1),CN( 130), AMTRC (130),AMTRN(130),AAMTRC(2), TRNSFM 2AAMTRN(2),OAMT(2,5),AAMT(2,4) TRNSFM TRNSFM TRNSFM ESTABLISH A SET OF CONSTANTS TRNSFM DATA((C(L),L =1,4)= 413. 1,. 8917,4.639,0.),((B1(L),L =1,4) = -155.6, TRNSFM 1 -. 002156,. 001621 , -3.223E- 15),((82(L),L= 1,4) =- 152.8, -.02696,.2384, TRNSFM 2 +1.512),((B3(L),L =1,4) =0.0,.3916,- 2.151,- 4.900E -03) TRNSFM TRNSFM CONVERT TO STORAGE LOCATIONS AND UNITS NEEDED IN THE SUBROUTINE TRNSFM COMPONENT UNITS IN THIS ROUTINE ARE EXPRESSED IN UG /SEGMENT SOIL TRNSFM TEMPERATURE UNITS ARE DEGREES C TRNSFM MOISTURE UNITS ARE BARS TRNSFM IF(ISET.LE.IFACT)17,18 $PL2 = ADOITI(I) /IFACT PL1 = ADDIT(I) /IFACT TPLANT = TPLANT + PLNH4(I) /IFACT + PLN03(I) /IFACT Page 68 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 6000 C C 612 N C C N C 310 N C 801 C C 600 N C 311 N C 615 N C 616 C C N N C C TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM SET INITIAL VALUES TRNSFM M =1 TRNSFM X = ILL TRNSFM K =1 TRNSFM TRNSFM ENTER LOOP TO DO COMPUTATIONS FOR EACH TIME INTERVAL TRNSFM DO 611 I =1,K TRNSFM TRNSFM ROUNTNE ENTER UREA TRNSFM PRESENT AT THE START OF A DAY DETERMINE`THE AMOUNT OF UREA TRNSFM TRNSFM L =1 TRNSFM AMT(1,L) = SAMT(M,L) +AAMT(M,L) TRNSFM TRNSFM CHECK FOR ZERO AMOUNT OF UREA TRNSFM IF(AMT(I,1).EQ.0.0) 310,801 TRNSFM TRNSFM SET RATE EQUAL TO ZERO FOR ZERO AMOUNT OF UREA TRNSFM R(I,L) = 0.0 TRNSFM GO TO 311 TRNSFM TRNSFM HYDROLYSIS COMPUTE RATE OF UREA TRNSFM R(I,L) = C( L)+( B1( L)+ ALOG10( T (M))) +(B2(L)*ALOGi0(AMT(I,L))) TRNSFM TRNSFM _ -AMT(I,L) R(I,L) 5.0) IF(R(I,L).GE. TRNSFM CORRECT RATE FOR LOW TEMPERATURES TRNSFM IF(T(M).LE.10.0) R(I,L) = R(I,L) *ALOG10(T(M)) /4.0 TRNSFM TRNSFM ADJUST RATE FOR LENGTH OF TIME INTERVAL TRNSFM R(I,L) = R(I,L) /X TRNSFM PRESENT AT THE START OF NEXT TIME INTER TRNSFM DETERMINE AMOUNT OF UREA TRNSFM AMT(I +1,L) =AMT(I,L) +R(I,L) TRNSFM TRNSFM CHECK FOR NEGATIVE AMOUNTS OF UREA TRNSFM IF(AMT(I+1,L))615,616,616 TRNSFM AMT(I +1,L) =0.0 TRNSFM TRNSFM ROUTINE ENTER ORGANIC TRNSFM L =2 TRNSFM TRNSFM DAY ADDED EACH ORGANIC OF AMOUNT COMPUTE THE TRNSFM IF(CN1(M).EQ.0.0) OAMT(M,L) = 0.0 TRNSFM OAMT(M,L) = 0.4 /CN1(M) +SAMT(M,2) IF(CN1(M).GT.0.0) TRNSFM PRESENT TRNSFM COMPUTE THE AMOUNTS OF AMMONIA N, ORGANIC N, AND NITRATE TRNSFM AT THE START OF A DAY TRNSFM TRNSFM AMT(1,L) = OAMT(M,L) + AAMT(M,2) TRNSFM AMT(113) = SAMT(M,3) + AAMT(M,3) AAMT(1,1) = UREA(J1) AAMT(1,2) = ORN(J1) ENH3 = 9NH4(J1)*CONVERT414.0E6 AAMT(1,3) = ANH3(J1) + ENH3 AAMT(1,4) = AN03(J1) SAMT(1,2) = AOR(J1) AAMTRN(1) = RN(J1) AAMTRC(1) = RC(J1) CN1(1) = CNR(J1) T(1) = TEM(J1) W(1) = ABS(TEN(J1)) /1030. SAMT (1,1)= SAMT(1,3) =SAMT(1,4) =0.0 SAMT(1,2) = SAMT(1,2) /CONVERT DO 6000 J =1,4 AAMT(1,J) = AAMT(1,J)1CONVERT N N Page 69 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 TRNSFM TRNSFM TRNSFM TRNSFM ANO RESIDUE-C OF RESIDUE-N AMOUNTS INITIAL THE C COMPUTE TRNSFM IF(CN1(M).EQ.0.0) AMTRN(1) = AAMTRN(M) TRNSFM + AAMTRN(M) IF(CN1(M)GT.0.0) AMTRN(1) = 0.4/CN1(M)*SAMT(M,2) TRNSFM AAMTRC(M) AMTï2C(1) = IF(CN1(M).EQ.0.0) TRNSFM IF(CN1(M)GT.0.0) AMTRC(1) = 0.4*SAMT(M,2) + AAMTRC(M) TRNSFM IF(AMTRC(1).LE.0.0.OR.AMTRN(1).LE.0.0)2002,2003 TRNSFM 2002 CN(1) = 10.0 TRNSFM GO TO 2004 TRNSFM TRNSFM COMPUTE INITIAL C/N RATIO C TRNSFM 2003 CN(1) = AMTRC(1)/AMTRN(1) TRNSFM TRNSFM MAKE CONSTANT ADJUSTMENTS ACCORDING TO C/N RATIO C TRNSFM 82(3) = 4.5 2004 IF(CN(I).LT.23.0) TRNSFM B3(2) = 1.6 IF(CN(I).LT.23.0) TRNSFM 83(2) _ .7832 IF(CN(I).GE.23.0) TRNSFM = .0008 81(3) IF(CN1I).GE.23.0) TRNSFM B2(3) _ .0002384 IF(CN(I).GE.23.0) TRNSFM B3(3) _ -2.1 IF(CN(I)Gc.23.0) TRNSFM TRNSFM COMPUTE RATE OF MINERALIZATION - IMMOBILIZATION C 751 R(I,L)=C(L)+(Bi(L)*T(M))+(82(L)*AMT(I,L))+(63(L)*ALOG10(AMT(I,3))) TRNSFM TRNSFM TRNSFM CORRECT RATE FOR LOW TEMPERATURES C TRNSFM R(I,L) = R(I,L)*ALOG10(T(M))/4.0 IF(T(M).LE.10.0) TRNSFM TRNSFM CORRECT RATE FOR LOW MOISTURES C TRNSFM = R(I,L)/ALOG10(W(M))*0.3 IF(W(M).GE.10.0) R(I,L) TRNSFM IF(R(I,L).LT.0.0.ANO.CN(I).GE.23.0) R(I,L) = 0.0 TRNSFM IF(R(I,L).LT.O.Q.AND.CN(I).LT.23.0) R(I,L) = ABS(R(I,L)) TRNSFM TRNSFM CORRECT RATE FOR C/N RATIO C TRNSFM 2.518) R(I,L) = R(I,L)*(1.848*ALOG10(CN(I)) TRNSFM IF(R(I,L))802,803,804 TRNSFM 802 IF(AMT(I,L).LT.AÉS(fi2(I,L))) R(I,L) _ -AMT(I,2) TRNSFM GO TO 803 TRNSFM 804 IF(AMT{I,3).LT.R(I,L)) R(I,L) = AMT(I,3) TRNSFM TRNSFM FOR OF TIME INTERVAL LENGTH ADJUST RATE C TRNSFM 803 R(I,L) = R(I,L)/X TRNSFM =0.0001 IF(AMT(I,2).EQ.0.0) AMT(I,2) TRNSFM TRNSFM CHECK FOR ZERO AMOUNT OF NITRATE-N C TRNSFM 307, 308 IF (AMT(I,4). EQ. 0.0) TRNSFM 307 R(I,5) = 0.0 TRNSFM GO TO 309 TRNSFM TRNSFM C COMPUTE RATE OF NITRATE-N IMMOBILIZATION 308 R(I,5) = (81(4) * EXP(T(M)))+ (82(4) * T(M)/(AMT(I,2)**2))+(B3(4)* TRNSFM TRNSFM 1(T(M)*(AMT(I,2)AMT(I,4)))/AMT(I,2)) TRNSFM IF(CN(I).LE.10.0)1,5 TRNSFM R(I,5) = R(I,5)*0.1 TRNSFM R(I12) = R(I,2)*0.005 TRNSFM 5 CONTINUE TRNSFM TRNSFM CORRECT RATE FOR LOW TEMPERATURES C TRNSFM IF(T(M).LE.10.0) R(I,L) = R(I,L)*ALOG10(T(?i))/4.0 TRNSFM TRNSFM CORRECT RATE FOR LOW MOISTURES G TRNSFM IF(W(M).GE.10.0) R(I,L) = R(I,L)/ALOG10(W(M))*0.3 TRNSFM 809 IF(AMT(I,4).LT.R(I,5)) R(I,5) = AMT(I,4) TRNSFM IF(R(I,5).LE.0.0) R(I,5) = ABS(R(I,5)) TRNSFM AMT(1,4) = SAMT(M,4) + AAMT(M,4) IF(AMT(I,3).EQ.0.0) AMT(I,3) = 0.0001 Page 10 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 C ADJUST RATE FOR LENGTH OF TIME INTERVAL 808 R(I,5) = R(I,5)/X C ENTER BRANCH ACCORDING TO C/N RATIO 309 IF(CN(I).LE.80.0.AND.CN(I).GT.23.0)2000,2001 C COMPUTE AMOUNT OF RESIDUE-C AT T + 1 2000 AMTRC(I+1) = AMTRC(I) - (30.*(R(I,L)+R(I,5))) C C COMPUTE AMOUNT OF RESIDUE-N AT T + 1 AMTRN(I+1) = AMTR.N(I) IF(AMTRC(I+1).L£.0.0.OR.AMTRN(I+1).LE.0.0) GO TO 1030 GO TO 1031 COMPUTE AMOUNTS OF RESIDUEN ANO R:ESIDUE-C AT T + 1 = AMTRC(I) - (30.*(ABS(R(I,L)-R(I,5))l) AMTRN(I+1) = AMTRN(I) - ABS(:R(I,L)) IF(AMT RC(I+1).LE.0.0.OR.AMTRN(I+1).LE.0.0) GO TO 1030 2001 AMTRC.(I+i) GO TO 1031 1030 CN(I+1) = 10.0 GO TO 1022 C COMPUTE C/N RATIO AT T + 1 1031 CN(I+1) = AMTRC(I+1)/AMTRN(I+1) 1022 IF(AMTRC(I+1).LE.0.0) AMTRC(I+1) = 0.0 IF(AMTRN(I+1).LE.0.0) AMTRN(I+1) = 0.0 If(I.EQ.K) AAMTRN(M+1) = AMTRN(I+1) IF(I.EQ.K) AAMTRC(M+1) = AMTrRC(I+1) AMT(I+1,L)=AMT(I,L)+R(I,L)+R(I,5) IF(AMT(I+1,L))620,621,621 620 AMT(I+1,L)=0.0 C C C C G G C TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSF M. TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM T RNSFM TRNSFM ENTER AMMONIA-N ROUTINE TRNSFM TRNSFM IF(AMT(I,4).EQ.0.0) AMT(I,4)=0.0001 TRNSFM TRNSFM CHECK FOR ZERO AMOUNT OF AMMONIA-N TRNSFM IF(AMT(I,3).c(1.0.0) 305, 753 TRNSFM 305 R(I,L) = 0.0 TRNSFM GO TO 306 TRNSFM TRNSFM COMPUTE RATE OF NITRIFICATION 753 R(I,L)=C(L)+(B1(L)'FT(M)*AMT(I,3))+(B2(L)*ALOG10(AMT(I,3)))+(B3(L)* TRNSFM TRNSFM 1ALOG10(AMT(I,4))) TRNSFM TRNSFM CORRECT RATE FOR LOW TEMPERATURES TRNSFM R(I,L) = R(I,L)*ALOG10(T(M))/4.0 IF(T(M).LE.10.0) TRNSFM TRNSFM CORRECT RATE FOR LOW MOISTURES TRNSFM IF(W(M).GE.10.0) R(I,L) = R(I,L)1ALOG10(W(M))*0.3 TRNSFM IF(R(I,L))815,816,817 TRNSFM R(I,L) = -AMT(I,4) 815 IF(AMT(I,4).LT.ABS(R(I,L))) TRNSFM GO TO 816 TRNSFM R(I,L) = AMT(I,3) 817 IF(AMT(I,3).LT.R(I,L)) TRNSFM TRNSFM ADJUST RATE FOR LENGTH OF TIME INTERVAL TRNSFM 816 R(I,L) = R(I,L) /X TRNSFM TRNSFM COMPUTE AMOUNT OF AMMONIA-N PRESENT AT T+1 TRNSFM 306 AMT(I+1,L)=AMT(I,L)-R(I,1)R(I,2)-R(I,3) TRNSFM IF(AMT(I+1,L))622,623,623 TRNSFM 622 AMT(I+1,L)=0.0 TRNSFM TRNSFM ENTER NITRATE-N ROUTINE TRNSFM 623 L=4 TRNSFM 621 L=3 C TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM Page 71 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM TRNSFM NEXT OF TIME STEP AMOUNTS FOR START C COMPUTE TRNSFM DO 632 L =1,4 TRNSFM AAMT(M +1,L) =AMT(K +1,L) TRNSFM TRNSFM C ENTER ROUTINE TO CHECK FOR CONVERGENCE OF PREDICTED OUTPUT TRNSFM IF(K.GT.1) GO TO 721 TRNSFM GO TO 722 TRNSFM A(L) = A(L) + 0.0001 721 IF(AAMT(M +1,L).EO.A(L)) TRNSFM IF(ABS(AAMT(M +1,L)- A(L)).LE.CH) GO TO 632 TRNSFM 722 A(L) =AAMT(M +1,L) TRNSFM 632 CONTINUE TRNSFM IF(A(1)- AAMT(M +1,1))633,634,633 TRNSFM 633 IF(A(2)- AAMT(M +1,2))635,634,635 TRNSFM 635 IF(A(3)- AAMT(M+1,3))636,634,636 TRNSFM 636 IF(A(4)- AAMT(M +1,4))641,634,641 TRNSFM X =2. *X 634 TRNSFM K =2*K TRNSFM TRNSFM C CHECK FOR MAXIMUM NUMBER OF ITERATIONS ALLOWED TRNSFM IF(K.GT.128) GO TO 300 TRNSFM GO TO 612 TRNSFM 300 CONTINUE TRNSFM 641 AOR(J1) =0.0 TRNSFM TRNSFM C CONVERT UNITS TO UG /SEGMENT TRNSFM 00 6001 J =1,4 TRNSFM AAMT(1,J) = AAMT(i,J) *CONVERT TRNSFM 6001 AAMT(2,J) = AAMT(2,J)''CONVERT TRNSFM MMMM = MMMM + 1 ORN(Ji) = AAMT(1,2) =SAMT(1,2)* 0.4 /CNR(J1)*CONVERT TRNSFM IF(MMMM.LT.Q TRNSFM CNR(J1) =0.0 TRNSFM TRNSFM COMPUTE DELTA VALUES FOR COMPONENTS C TRNSFM DELN03 = AAMT(2,4) - AAMT(1,4) TRNSFM RATIO = AAMT(2,3) /AAMT(1,3) TRNSFM FIRST = AAMT(1,3) - ENH3 TRNSFM FINAL = FIRST *RATIO TRNSFM FINALI = BNH4(J1)4RATIO TRNSFM D LNH3 = FINAL - FIRST TRNSFM DELORGN = AAMT(2,2) - AAMT(1,2) TRNSFM DELUREA = AAMT(2,1) - AAMT(1,1) TRNSFM DELBNH4 = FINAL/ - BNH4(J1) TRNSFM DELRN = AAMTRN(2) - RN(J1) TRNSFM DELRC-= AAMTRC(2) - RC(J1) TRNSFM IF(DELBNH4.LE.0.0) Sis = 0.0 TRNSFM TRNSFM C RETURN TO SUBROUTINE COMBINE TRNSFM RETURN TRNSFM END XCHANGE ,EXAMG,EXHCO3,EXC03,EXSO4,EXC XCHANGE(J,EXNH3, EXCA, EXANA SUBROUTINE XCHANGE 1L,EXBNH4) XCHANGE XCHANGE C THIS IS THE EXCHANGE SUBROUTINE XCHANGE COMPUTE AMOUNT OF NITRATE -N PRESENT AT T +1 IF(R(I,5).GT.R(I,3))900,901 900 IF (CN(I).LE.10.0.AND.AMT(I,4).LE. 6 .0)AMT(I +1,2) =AMT(I +i,2)- (R(I,5 1)- R(I,3)) IF (CN(I).LE.10.D.AND.AMT(I,4).LE. 6.0) R(I,5) =R(I,3) 901 CONTINUE AMT (I +1,L) =AMT(I,l) +R(I,3)- R(I,5) IF(AMT(I +1,L))624,625,625 624 AMT(I+1,L) =0.0 625 CONTINUE 611 CONTINUE G ) Page 72 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255' 256 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 2 3 4 5 6 COMMON /XXX /DELX,DELT,MM,START,BO(25 ),TEN(25 ),CHECK(25 ),MOISIN 1(25 ),CMH202(25 ),MOISOUT(25 ),AN03(25 ),ANHZ(25 ),UREA(25 ),ORN 2(25 ),CZ(25 ),ANZ(25 ),AMZ(25 ),HCOZ(25 ),CY(25 ),COZ(25 ),SOZ(25 3),EZ(25 ),CX(25 ),SAZ(25 ),XXZ(25 ),CASZ(25 ),AGSZ(25 ),BNHZ(25 ), 4EY(25 ),CN1(25 ),SAMT(25 ),RN(25 ),RC(25 ),TEM(25 ),CAZ(25 ),Q,CRO 1P, XTRACT, SUMNO3, THOR( 4),TO,IDAY,U3(25),CH,CH1,IRERUN DIMENSION CMH201(25) DATA (TES = 0.000001) SET SEGMENT VOLUMES C CMH2O1(J) =CMH2O2(J) MOISTURE CONTENT ON B1 = CMH2O1(J) / (8O (J) *DELX) B1 = 81 +100. C--- COMPUTE A PERCENT BASIS C COMPUTE SEGMENT VOLUMES BASED ON INITIAL SOIL ANALYSES IF(CHECK(J).EQ.0.0)CMH2O1(J) =XTRACT *DELX *BD(J) C CONVERT UNITS FROM UG /SEGMENT TO MOLES /LITER C RESET STORAGE LOCATIONS FOR USE IN THIS ROUTINE ANH4 = ANHZ(J) /CMH2O1(J) /14000. A = CZ(J) /CMH2O1(J) /40080. S = ANZ(J) /CMH2O1(J)/22990. F = AMZ(J) /CMH201(J)/24320. HCO3 = HCOZ(J) /CMH201(J) /61000. CO3 = COZ(J) /CMH2O1(J) /60000. H = CY(J) /CMH2O1(J) /35460. G = SOZ(J) /CMH2O1(J) /96100. $XXT = XXZ(J) $CT = CX(J) $SAT = SAZ(J) ET = EZ(J) $BNH4 = BNHZ(J) CASO = CASZ(J) $AGSO = AGSZ(J) $ CAL = CAZ(J) EC = EY(J) 1005 IF(CHECK(J).EQ.0.0)200,201 CALL THE EQULIBRIUM EXCHANGE SUBROUTINE IF THIS IS THE FIRST TIME INTERVAL C C 200 CALL EQEXCH( A, F, S, H,G,HCO3,CO3,EC,ANH4,ET,CT,SAT, ICASO,AGSO,BNH4,U) ET = ET /2. CT = CT /2. A = A /2. F /2. XXT = XXT /2.E5 DA =0.707 F = 201 0 =0,67 DNH4 =0.22 8 = 81 IF(CHECK(J).EQ.0.0) B = XTRACT *100. IF(CHECK(J).NE.0.0) U= SQRT( 2.0 *(A +F +G +CO3) +0.5 *(S +HCO3 +H)) IF (CAL) 1000,602,603 602 IK =1 AAA =452. GO TO 604 603 IK =2 ZE =( A «HCO3 * *2 *EXP(- 2.341 *U /(1. +U))) AAA =8 AAA =(AAA* *1.68) *ZE 604 ZE =AAA /(B1* *1.68) 299 IF(CHECK(J).EQ.0.0)299,298 CONTINUE RATIO =B /Bi SG =G *RATIO A =A *RATIO XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE. XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE, _ Page 73 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 $H=H*RATIO F=F*RATIO 3CAS0 = CASO*RATI-0 S=S*RATIO 3ANH4=ANH4*RATIO AGSO=AGSO*RATIO CO3 = CO3*RATIO HCO3 = HCO3*RATIO 8 = 1.E5/8 298 24 A1=A IF(XXT)4,4,26 4 U=SQRT (2. 0* (A+F+G)+0. 5* (S+H+HCO3) ) (-9.366*U/(1.0+U)) AA=EXP IF(2.4E-5-A*G*AA)26,18,19 26 X=0.0 U=SQRT(2.0*(A+F+G)+0.5*(S+H+HCO3)) BB= A+G EX=(9.366*U)1(1.0+U) (EX) CC=A*G-(2.4E-5)*EXP R=SQRT(B8*BB-4.0*CC) X=(-88+R) /2.0 CAS1=4.897E-3-CASO DEL=8*XXT-CAS1 IF(DEL-X)27,28,28 X=XXT*8 27 XXT=0.0 CAS1=0.0 A=A+X G=G+X U=SQRT(2.0*(A+F+G)+0.5*(S+H+HCO3)) AA=EXP (-9.366*U/(1.+U)) 7 B8=-(4.9E-3+AA*A+AA*G) CC=A4*A*G-4.9E-3*CASO XXXX=BB*98-4.0*AA*CC IF(XXXX) 35,35,36 35 X1=0.0 GO TO 37 36 X1=(-R8-S(IRT(XXXX))/(2.0*AA) 37 CASO=CASO+X1 A=A-X1 G=G-X1 GO TO 44 IF (G) 1,1,6 6 IF (A) 1,1,7 44,44,7 i IF (CASO) 28 A=A+X 18 G=G+X XXT=XXT-X/B CASO=CASO+CAS1 XXT=XXT-CAS11B 44 A2=A 80,181,80 IF (S) 181 IF(SAT)80,515,80 80 IJ=2 404 IF(SAT-ET)402f403,403 402 Z=SAT/10. Z1=Z GO TO 5 403 Z=ET/10. Z1=2 =X=EXP ((-2.341*U)/(1.0+U)) AA=-4.0*0A*DA*3*8 B8=4.0*R*(EX+2.0*DA*DA*ET*B+DA*DA*S) CC=4.0*EX*(A+SAT*8)-4.0*OA*011*8*ET*(B*ET+2.0*S)-0A*0A*S*S 0O=SAT*EX*(4.0*A+SAT*B)+2.0*DA*DA*ET*S*(2.0*3*ET+S) EE=SAT*SAT*A*EX-DA*DA*S*S*ET*ET 81 ZZ=-((((AA*Z+88)*Z+CC)*Z+DD)*Z+EE) ZZZ=(((4.0*AA*Z+3.0*8B)*Z+2.0*CC)*Z+DD) IF(ABS(ZZ).LT.TES.OR.ABS(ZZZ).LT.TES) GO TO 515 5 Page 74 XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE 73 74 75 76 77 XCHANGE 78 79 XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE xCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE 80 8i 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 XCHANGE, 133 XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE 134 135 136 137 138 83 552 551 550 510 zz=zz/zzz IF(ABS(ZZ).LT.TES.OR.ABS(Z) zzz=zz/z 2=Z+ZZ IF(ABS(ZZZ)-.001)83,83,81 A=A+B*Z IF(A)510,510,512 SAT=SAT-2.*Z ET=ET+Z S=S+2.*B*2 A=A-8*Z .LT.TES) GO TO 515 Z=-Z1 GO TO 81 512 S=S-2.*B*2 IF 550,550,513 (S) 513 ET=ET-Z IF (ET)551,551,514 514 SAT=SAT+2.0*Z IF 552,552,515 (SAT) 515 A3=A BB=A+B*(CT+D*ET)+O*F AA=B*(1.0-D) CC=(A*CT-0*F*ET) R=SQRT (BB+BB-4.0*AA*CC) Y=(-BB+R)/(2.0+AA) A=A+B*Y F=F-B*Y ET=ET-Y CT=CT+Y A4=A AA = 8*(1.0-ONH4) BB = ANH4 + 43*(SAT+ONH4*BNH4) CC = ANH4*SAT - DNH4*S*8NH4 + ONH4*S R=SQRT(BB*BB-4.0*AA*CC) Y=(-BB+R)/(2.0*AA) BNH4 = BNH4 - Y SAT = SAT + ANH4 = ANH4 S = S - Y + B*Y BY IF(G)790,790,791 791 IF(F)790,790,792 792 AA=EXP(-9.366*U/(1.+U)) B8=-(5.9E-3+AA*F+AA*G) CC=AA*F*G-5.9E-3*AGSO XXXX=BB*BB-4.0*AA+CC IF(XXXX)793,793,794 793 X1=0.0 GO TO 795 794 X1=(-BB-S(IRT(XXXX))/(2.0*AA) 795 AGSO=AGSO+X1 F=F-X1 G=G-X1 790 CONTINUE GO TO (600,601),IK 601 AA=4.0 B8=4.*HCO3+A CC=HCO3**2+4.*A*HCO3 OO=A*HCO3**2-ZE*EXP (2.341*U/(1.+U)) IF(HCO3-A)61,61,62 61 Z=-HCO3/4, GO TO 650 62 Z=-A/2. 650 Z1=Z 63 ZZ=-(((AA*Z+BB)*Z+CC)*Z+OD) ZZZ=((3.0*AA*Z+2.0*BB)*Z+CC) IF(ABS(ZZ).LT.TES.OR.ABS(ZZZ).LT.TES) GO TO 600 Page 75 XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 ZZ=ZZIZZZ IF(ABS(ZZ).LT.TES.OR.ABS(Z) ZZZ=ZZ/Z Z=Z+ZZ IF(ABS(ZZZ)-.001)64,64,63 64 A=A+Z HCO3=HCO3+2.*Z IF(HCO3)752,752,651 752 HCO3=HCO3-2.*Z A=A-Z Z=-Z1 .LT.TES) GO TO 600 GO TO 63 651 IF(A) 752,752,753 753 CAL=CAL-Z 600 ZX=(A*HCO3**2*EXP(-2.341*U/(1.+U))) IF(ZX-ZE)606,605,605 605 IK=2 606 DEL=A-A1 IF(DEL+CH1)24,48,48 48 IF(DEL-CH1)49,49,24 49 DEL=A-A2 IF(DEL+CH1)24,50,50 IF(DEL-CH1)51,51,24 51 DEL=A-A3 IF(DEL+CH1)24,52,52 52 IF(DEL-CH1)8,8,24 8 DEL=A-A4 IF(DEL+CH1)24,66,66 66 IF(DEL-CH1)67,67,24 1000 CONTINUE 67 CONTINUE IF(CHECK(J).EQ.0.0) CMH2O1(J) = CMH202(J) ANH4 = ANH4*CMH2O1(J)*14000. A = A*CMH2O1(J)*40080. S = S*CMH2O1(J)*22990. F = F*CMH2O1(J)*24320. HCO3 = HCO3*CMH2O1(J)*61000. H = H*CMH2O1(J)*35460. CO3 = CO3*CMH2O1(J)*60000. G = G*CMH2O1(J)*96100. IF(CHECK(J).LQ.0.0)400,401 ANHZ(J) = ANH4 400 $CZ(J) = A ANZ(J) = S gAMZ(J) = F HCOZ(J) = HCO3 $COZ(J) = CO3 CY(J) = H $SOZ(J) = G BNHZ(J) = BNH4 CHECK(J)=CHECK(J)+1. 401 CONTINUE 50 C C COMPUTE DELTA VALUES FOR COMPONENTS EXNH3 = ANH4 - ANHZ(J) $EXCA = A - CZ(J) EXANA = S - ANZ(J) $EXAMG = F - AMZ(J) S6EXC03 = CO3 - COZ(J) EXHCO3 = HCO3 - HCOZ(J) EXCL = H - CYO) $EXSO4 = G - SOZ(J) EXBNH4 = 9NH4 - BNHZ(J) EZ(J) = ET $CX(J) = CT SAZ(J)=SAT $XXZ(J)=XXT $AGSZ(J)=AGSO CASZ(J)=CASO CAZ(J)=CAL $EY(J)=EC XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE XCHANGE RETURN TO SUBROUTINE COMBINE XCHANGE RETURN XCHANGE ENO XCHANGE SUBROUTINE EQEXCH(CA,AMG,SOS,CL,SO,HCO3,CO3,£C,ANH4iE5iC5,SA5,CAS0 EQEXCH 1,AGSO,BNH4,U) EOEXCH EQEXCH Page 76 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 249 250 251 252 253 254 255 256 257 258 259 260 261 262 263 264 265 266 267 2 3 4 THIS SUBROUTINE COMPUTES THE AMOUNTS OF IONS CONTAINED ON THE EXCHANGE COMPLEX (BASED ON INITIAL SOIL ANALYSIS) C C DA=2.00 0=0.67 ONH4=0.22 CASO=0.0 U=SQRT(2.0*(CA+AMG+SO+CO3)+0.5*(SOS+HCO3+CL)) AGS0=0.0 42 ACT2=EXP(-9.366*U/(1.0+U)) IF (SO) 1000,713,712 712 AA=ACT2*ACT2 BB=ACT2* (10.8E-3+ (ACT 2* (AMG+CA-S0) ) ) CC=28.91E-6+(ACT2*(AMG*4.9E-3+(CA*5.9E-3)(SO*10.8E-3))) OD=-S0*28.91E-6 800 Z=SO/2, 850 Z1=Z 863 ZZ=(((AA*Z+BB)*Z+CC)*Z+OD) ZZZ=((3.0*AA*Z+2.0*BB)*Z+CC) ZZ=ZZ/ZZZ ZZZ=ZZIZ Z=Z+ZZ IF (ABS(ZZZ).001)840,840,863 SOT=SO SO=Z IF(SO)710,710,711 710 SO=SOT Z=Zi GO TO 863 711 CASX=SO*CA*ACT2/(4.9E-3+ACT2*S0) CX=CA-CASX 840 AGSX=SO*AMG*.ACT2/(5.9E3+ACT2*SO) AMX=AMG-AGSX UU-SQRT(2.*(CX+AMX+SO+CO3)+0.5*(SOS+HCO3+CL)) IF(ABS(UU/U1.)-1.0E-4) 40,40,41 41 U=UU SO=SOT GO TO 42 40 CASO=CASX AGSO=AGSX CA=CX AMG=AMX 713 ACT1=SQRT(ACT2) ACTM=SQRT(ACT1) ACTM=SQRT(ACTM) CA=CA*2. AMG=AMG*2. 1000 E5=EC/((ACTM*SOS/(DA*SQRT(ACT1*CA)))+1.+(0*ACT1*AMG/(ACT1*CA))) SA5=ACTM*SOS*E5/(SQRT(ACTi*CA)*DA) C5=EC-E5-SA5 BNH4 = (SA5*ANH4)/(SOS*ONH4) RETURN END C EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EOEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH EQEXCH E QEXCH EQEXCH SUBROUTINE FL(J,FLNO3,FLNH3,FLUREA,FLCA,FLANA,FLAMG,FLHCO3,FLCL,FI FL FL 1CO3,FLSO4) FL FL THIS IS THE SOLUBLE COMPONENT LEACHING SUBROUTINE FL FL COMMON/XXX/DELX,DELT,MM,START,BD(25 ),TEN(25 ),CHECK(25 ),MOISIN FL 1(25),ORMOIS(25),MOISOUT(25),BN03(25),BNH3(25),BREA(25),ORN FL 2(25),BA(25),BNA(25),BMG(25),BC03(25),BL(25),903(25),BO4(25 3),E5(25 ),C5(25 ),SA5(25 ),XX5(25 ),CASO(25 ),AGSO(25 ),BNH4(25 ), FL 4EC(25 ),CN1(25 ),SAMT(25 ),RN(25 ),RC(25 ),TEM(25 ),CAL(25 ),Q,CRO FL iP,XTRACT,SUMNO3,THOR(4),TO,IDAY,US(25),CH,CHI,IRERUN,IShiCH,CUMSUM, FL FL iSUMOUT FL COMiMON/GIRL/UREAltUREAZONti31AQNH3LON011_,iZN032kCA1._,ANA1ALAMQii Page 77 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 2 3 4 5 6 T 8 9 10 11 12 13 1.4 1HC031,CL1,C031,SO41,K DIMENSION ANH3(25),AN03(25),UREA(25),CA(25),ANA(25),AMG(25),HCO3(2 15),CL(25),CO3(25),SO4(25) INTEGER Q REAL MOISIN,MOISOUT IF(J.NE.2) GO TO 00 18 I=1,Q 1 18 ANH3(I)=8NH3(I) ?AN03(I)=BN03(I) bUREA(I)=BREA(I) 3CA(I)=8A(I) ANA(I)=BNA(I) $AMG(I)=BhIG(I) $HCO3(I)=9CO3(I) $CL(I)=8L(I) CO3(I)=803(I) $SO4(I)=B04(I) CONTINUE C SET Q+1 VALUES EQUAL TO Q VALUES 1 ORMOIS(Q+1) = ORMOIS(Q) ANH3(Q+1) = ANH3(Q) $AN03(Q+1) = ANO3(Q) $CA(Q+1) = CA(Q) UREA(Q+1) = UREA(Q) ANA(Q+1) = ANA(Q) ñAMG(Q+1) = AMG(Q) $CL(Q+1) = CL(Q) HCO3(Q+1) = HCO3(Q) $SO4(Q+i) = SO4(Q) CO3(Q+1) = CO3(Q) CONTINUE COMPUTE COEFIN ANO COEFOUT IF(MOISIN(J).LT.0.0)2,3 COEFIN = MOISIN(J)/ORMOIS(J) C 2 GO TO 4 IF(ORMOIS(J-1).GT.0.0) GO TO 14 COEFIN=0.0 GO TO 15 14 COEFIN=MOISIN(J)/ORMOIS(J-1) 15 CONTINUE IF(MOISOUT(J).LT.0.0)5,6 COEFOUT = MOISOUT(J)/ORMOIS(J+1) 3 4 5 GO TO 6 7 8 7 COEFOUT = MOISOUT(J)/ORMOIS(J) IF(COEFIN.LT.0.0) 8:9 K=J GO TO 10 9 10 li K=J-1 IF(COEFOUT.LT.0.0)11,12 L=J+1 GO TO 13 12 L=J C COMPUTE DELTA VALUES FOR AMOUNTS CONTINUE IF(ABS(COEFIN).GT.1.0) COEFIN = A8S(COEFIN)/COFFIN IF(ABS(COEFOUT).GT.1.0) COEFOUT = ABS(COEFOUT)/COEFOUT $0NO32=COEFOUT*AN03(L) ON031=COEFIN*AN03(K) $ONH32=COEFOUT*ANH3(L) ONH31=COEFIN*ANH3(K) $UREA2=COEFOUT*UREA(L) UREA1=COEFIN*UREA(K) CA1=COEFIN*CAEK) $CA2=COEFOUT*CA(L) $ANA2=COEFOUT*ANA(L) ANA1=COEFIN*ANA(K) AMG1=COEFIN*AMG(K) $AMG2=COEFOUT*AMG(L) HC031=COEFIN*HCO3(K) SHC032=COEFOUT*HCO3(L) CLI=COEFIN*CL(K) $CL2=COEFOUT*CL(L) CO31=C0EFIN*CO3(K) $C032=COEFOUT*CO3(L) SO41=COEFIN*SO4(K) $SO42=COEFOUT*SO4(L) FLNO3 = 0N031 - ON032 FLNH3 = ONH31 - 0NH32 FLUREA = UREA1 - UREA2 FLCA = CA1 - CA2 FLAMA = ANA1 - ANA2 FLAMG = AMG1 - AMG2 13 Page 78 FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL FL 15 16 17 18 19 20 22 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 FLHCO3 = HC031 - HC032 FLCL = CL1 - CL2 FLCO3 = CO3i - C032 FLSO4 = S041 SO42 FL FL FL FL FL FL FL FL RETURN TO SUBROUTINE COMBINE RETURN C END UPTAKE UPTAKE PLANT NITROGEN UPTAKE SUBROUTINE UPTAKE UPTAKE UPTAKE COMMON /XXY /ICHECK,ICOUNT,CONV, K, K1,CROP,FACT UPTAKE COMMON /XXX/ ELX, ELT,MS,WTART,BO(25 ),TEN(25 ),CHECK(25 ),MOISIN UPTAKE 1(25 ),CMH2O1(25 ),MOISOUT(25 ),AN03(25 ),ANH3(25 ),UREA(25 ),ORN 2(25 ),CA(25 ),ANA(25 ),AMG(25 ),HCO3(25 ),CL(25 ),CO3(25 ),SO4(25 UPTAKE 3),E5(25 ),C5(25 ),SA5(25 ),XX5(25 ),CASO(25 ),AGSO(25 ),BNH4(25 ), UPTAKE 4EC(25 ),CN1(25 ),SAMT(25 ),RN(25 ),RC(25 ),TEM(25 ),CAL(25 ),Q,SRO UPTAKE 1P, XTRACT,SUMN03,THOR(4),TO,IOAY,V ( 25),CH,CH1,IRERUN,ISWCH,CUMSUM, UPTAKE UPTAKE iSUMOUT,REDUCE UPTAKE REAL KP2,K,K1 UPTAKE INTEGER CROP UPTAKE DIMENSION KP2(6,3),UPTK(24) UPTAKE IF(CROP.EQ.1) GO TO 15 IF(ICHECK.EQ.0)1,2 UPTAKE UPTAKE ICHECK = ICHECK + 1 UPTAKE UPTAKE READ ROOT DISTRIBUTION UPTAKE READ 4,(KP2(J,3),J =1,6) UPTAKE READ PLANT UPTAKE OF N DATA FROM CAROS UPTAKE UPTAKE READ 3, (UPTK(J),J =1,24) UPTAKE PRINT ROOT DISTRIBUTION UPTAKE PRINT 11, (KP2(J,3),J =1,6) UPTAKE UPTAKE DO 6 J =1,24 UPTAKE UPTK(J) = UPTK(J) *CONV UPTAKE PRINT PLANT UPTAKE OF N DATA UPTAKE UPTAKE PRINT 12, (J,UPTK(J),J =1,24) PRINT 10 UPTAKE UPTAKE CONTINUE UPTAKE IF(I.EQ.2) ICOUNT = ICOUNT + 1 UPTAKE D = DELX *(I 1.) DEL = OELX /30.5 UPTAKE UPTAKE U = UPTK(ICOUNT) UPTAKE UPTAKE ADJUST UPTAKE VALUES FOR LENGTH OF TIME INTERVAL U= U /15.*OELT UPTAKE UPTAKE FOR SIZE OF DEPTH SEGMENT ANO ROOT DISTRIB UPTAKE ADJUST UPTAKE VALUES UPTAKE UTION UPTAKE IF(D.LE.30.5) U = U *KP2(1,CROP) *DEL U= U *KP2(2,CROP) *DEL UPTAKE IF(D.GT.30.5.AND.D.LE.61.0) U= U *KP2(3,CROP) *DEL UPTAKE IF(D.GT.61.0.AND.D.LE.91.5) U= U*KP2(4,CROP) *DEL UPTAKE IF(D.GT.91.5.AND.O.LE.122.) U= U *KP2(5,CROP) *DEL IF(D.GT.122..AND.D.LE.153.) UPTAKE UPTAKE U =U *KP2(6,CROP) *DEL IF(D.GT.153..ANO.O.LE.183.) UPTAKE IF(D.GT.183.AND.D.LE.214.)8,9 UPTAKE IF(CROP.EQ.2) U = U *0.08 *OEL UPTAKE IF(CROP.EQ.1) U = 0.0 UPTAKE IF(D.GT.214.) U = 0.0 UPTAKE UPTAKE DISTRIBUTE THE N UPTAKE BETWEEN NO3 AND NH4 $PLNH4 = -U *K1 PLNO3 = -U *K UPTAKE GO TO 16 UPTAKE SUBROUTINE UPTAKE(I,PLN03,PLNH4,OELT,DELX) C C C i C C C 6 C 2 C 7 C C 8 9 C Page 79 81 82 83 84 85 86 87 88 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 UPTAKE UPTAKE 16 UPTAKE UPTAKE UPTAKE UPTAKE FORMAT(10X,F10.0) 3 UPTAKE FORMAT(6F10.0) 4 UPTAKE FORMAT(1H1) 10 FORMAT( / /10X *PLANT NITROGEN UPTAKE DATA INPUT FROM CARDS* / /10X*R00 UPTAKE 11 61.0 CM *3X *61.0 - 91.5 UPTAKE 35.5 CM *3X *35.5 17. DISTRIBUTION * /10X' 0 UPTAKE -*//1)(,6F16.2) *153 CM *3X CM 153 *3X *122 CM 122 2CM *3X'91.5 FORMAT( / /10X *TOTAL PLANT UPTAKE OF NITROGEN(UG /15 DAYS)' / /(10X,I3, UPTAKE 12 UPTAKE 1F10.2)) UPTAKE ENO MCHECK SUBROUTINE MCHECK MCHECK MCHECK WITH NITROGEN OF STATUS MASS BALANCE THE COMPUTES THIS SUBROUTINE C MCHECK RESPECT TO THE SYSTEM C MCHECK MCHECK COMMON /EEE /PSUM,DIFNH4,DIFNO3,TPLANT MCHECK COMMON /XXX /DELX,DELT,MS,WTART,BD(25 ),TEN(25 ),CHECK(25 ),MOISIN MCHECK ),ORN ),UREA(25 ),ANH3(25 ),AN03(25 1(25 ),CMH2O1(25 ),MOISOUT(25 MCHECK 2(25 ),CA(25 ),ANA(25 ),AMG(25 ),HCO3(25 ),CL(25 ),CO3(25 ),SO4(25 3),E5(25 ),C5(25 ),SA5(25 ),XX5(25 ),CASO(25 ),AGSO(25 ),BNH4(25 ), MCHECK 4EC(25 ),CN1(25 ),SAMT(25 ),RN(25 ),RC(25 ),TEM(25 ),CAL(25 ),Q,SRO MCHECK 1P, XTRACT,SUMNO3,THOR(4),TO,IDAY,U ( 25),CH,CHI,IRERUN,ISWCH,CUMSUM, MCHECK MCHECK 1SUMOUT MCHECK MCHECK INTEGER Q MCHECK MCHECK S1 = 0.0 MCHECK FA = DELX *14.E6 MCHECK MCHECK IN SYSTEM MASS NITROGEN OF COMPUTE CURRENT C MCHECK 00 1 J =1,Q + MCHECK ANO3(J) + + ORN(J) *FA UREA(J) S1 = S1 + ANH3(J) + BNH4(J)48O(J) 1 MCHECK MCHECK C----- COMPUTE INITIAL MASS OF NITROGEN IN SYSTEM MCHECK -CUMSUM + PSUM SUMOUT IF(S2.EQ.0) S2 = S1 MCHECK MCHECK COMPUTE CHANGE IN STORAGE FOR NITROGEN C MCHECK S3 = S1 - S2 MCHECK PSUM1 = ABS(TPLANT) MCHECK MCHECK FOR NITROGEN COMPUTE TOTAL INPUT - TOTAL OUTPUT C MCHECK +PSUM -DIFNH4 -DIFNO3 SUMOUT OUTIN = CUMSUM MCHECK ISWCH = 0 MCHECK PRINT 99 MCHECK MCHECK PRINT VALUES COMPUTED ABOVE C MCHECK OIFNO3) PPP = ABS(PSUM - DIFNH4 MCHECK PRINT 100, S2,CUMSUM,SUMOUT,PPP ,OUTIN,S3,PSUM1 MCHECK PRINT 98 MCHECK RETURN MCHECK MCHECK MCHECK FORMAT(1H1 / / //) 98 MCHECK //) FORMAT( / 99 FORMAT(5X *SUMMARY OF NITROGEN BALANCE FOR SYSTEM' /10X *INITIAL NITR MCHECK 100 ADDED TO SYSTEM = *,E21.6, MCHECK 10GEN CONTENT = *,E20.6,2X *UG * /10X *TOTAL MCHECK 22X *UG * /10X *TOTAL -N LEACHED FROM SYSTEM = *,E17.6,2X *UG * /i0X *TOTAL F MCHECK OUTPUT TOTAL INPUT * /10X *TOTAL 3 UPTAKE BY PLANTS =4-,E20.6,2X*UG 40R N -*,E20.6,2X *UG* /10X *CHANGE IN N STORAGE SINCE START OF RUN =' MCHECK 5,E14.6,2X*UG * / /10X *TOTAL -N UPTAKE BY PLANTS(ATTEMPTED) = *,E20.6,2X MCHECK MCHECK 6 *UG*) MCHECK END 15 PLNO3 = -V(I) *K +FACT CONTINUE RETURN $PLNH4 = -V(I) *K1 *FACT N Page 80 N 60 61 62 63 64 65 66 67 68 69 70 71 72 73 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 SUBROUTINE TEMP C C C C C 1 C 23 C C 21 C 20 C C TEMP TEMP THIS SUBROUTINE READS IN TEMPERATURES FOR THE TEMPERATURE HORIZONS TEMP AND STORES THEM IN THE PROPER ARRAY LOCATIONS TEMP TEMP TEMP COMMON /XXX /DELX,DELT,MS,WTART,B0(25 ),TEN(25 ),CHECK(25 ),MOISIN TEMP 1(25 ),CMH2O1(25 ),MOISOUT(25 ),AN03(25 ),ANH3(25 ),UREA(25 ),ORN TEMP 2(25 ),CA(25 ),ANA(25 ),AMG(25 ),HCO3(25 ),CL(25 ),CO3(25 ),504(25 TEMP 3),E5(25 ),C5(25 ),SA5(25 ),XX5(25 ),CASO(25 ),AGSO(25 ),9NH4(25 ), TEMP 4EC(25 ),CNI(25 ),SAMT(25 ),RN(25 ),RC(25 ),TEM(25 ),CAL(25 ),Q,CRO TEMP IP,XTRACT,SUMN03,THOR(4),TO TEMP TEMP INTEGER Q,TO,CROP TEMP TEMP DIMENSION TTEM(4) TEMP TEMP TEMP TEMP TEMP READ TEMPERATURES IN DEGREES C READ (8) (TTEM(J),J =1,TO) TEMP TEMP TEMP TEMP COMPUTE BOTTOM OF TEMPERATURE HORIZON TEMP KK = THOR(L) /DELX + 1.1 TEMP DO 23 J =N,KK TEMP TEMP STORE TEMPERATURES TEMP TEM(J) = TTEM(L) TEMP TEMP CHECK FOR LAST HORIZON TEMP IF(KK.EQ.(1)20,21 TEMP TEMP RESET COUNTERS TEMP N =KK + 1 $L = L + 1 TEMP GO TO 1 TEMP TEMP RETURN TO MAIN PROGRAM TEMP RETURN TEMP ENO TEMP SUBROUTINE PRNT(IPRINTI,IPRINTJ) PRNT PRNT THIS SUBROUTINE PRINTS CONTROL AND INPUT DATA PRNT PRNT COMMON/ ABLE / TITLE( 10), SMONTH, MM, O, IPRINT,JPRINT,INK,IPUNCH,ISTOP, PRNT IITEST, IREADP, IMASS, IADO (25),IORNAP(5),HOR(9),TOTN(99), YEAR PRNT , 2AIRR( 9), IRR( 25), TT( 60), FERT( 7), OFERT (3),NORGIN,NFERTIN,NTEMPIN, PRNT 3ITOT,JTOT,IRTOT,NT PRNT COMMON /XX2 /Ai,A2,A3,X PRNT COMMON /YYY /START,IDTE,MONTH,I,LL PRNT COMMON/ XXY /ICHECK,ICOUNT,CONV,PK,PK1,CROP PRNT COMMON /XXX /DELX,DELT,MS,WTART,BD(25 ),TEN(25 ),CHECK(25 ),MOISIN PRNT 1(25 ),CMH2O1(25 ),MOISOUT(25 ),AN03(25 ),ANH3(25 ),UREA(25 ),ORN PRNT 2(25 ),CA(25 ),ANA(25 ),AMG(25 ),HCO3(25 ),CL(25 ),CO3(25 ),SO4(25 PRNT 3),E5(25 ),C5(25 ),SA5(25 ),XXS(25 ),CASO(25 ),AGSO(25 ),BNH4(25 ), PRNT 4EC(25 ),CN1(25 ),SAMT(25 ),RN(25 ),RC(25 ),TEM(25 ),CAL(25 ),Q,SRO PRNT 1P, XTRACT,SUMNO3,THOR(4),TO,IDAY,U ( 25),CH,CHI,IRERUN,ISWCH,CUMSUM, PRNT ISUMOUT,REDUCE PRNT PRNT INTEGER TITLE,SMONTH,START,O,TO,YEAR PRNT PRNT PRNT PRINT TITLE PRNT PRINT 100,TITLE PRNT IF(IPRINTI.EQ.2)._GO TO 1 PRNT SET COUNTERS L =1 $N =2 Page 81 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 C C 1 C C C 10 PRINT BASIC CONTROL CARD PARAMETERS PRINT 101, SMONTH,XTRACT, START, CROP,LL,PK,HM,PKisDELX,CH,DELT, 1CH1 ,O,A1,TO,A2,ISTOP,YEAR,REDUCE PRINT I -O CONTROL PARAMETERS PRINT 102, IPRINT, IREAOP ,JPRINT,ITEST,INK,IMASS,IRERUN ,IPRINTI, IIPUNCH,IPRINTJ RETURN ENTRY PRIT1 SKIP PAGE PRINT 103 PRNT PRINT TEMPERATURE HORIZONS PRINT 104, (THOR(J),J =1,TO) PRINT 109 REWIND 8 PRNT PRNT PRINT TEMPERATURES DO 10 J =1,NT READ (8) (TT(I),I =1,TO) PRINT 105, J, (TT(I),I =1,TO) REWIND 8 C SKIP PAGE PRINT 103 C PRINT WATER ANALYSIS HEADING PRINT 107 C PRINT IRRIGATION WATER ANALYSIS PRINT 108, (AIRR(I),I =1,9) C PRINT IRRIGATION APPLICATION DATES PRINT 110, (ItR(I),I =1,IRTOT) C PRINT FERTILIZER APPLICATION DATES PRINT 111, (IADD(I),I =1,ITOT) PRINT 112 REWIND 9 DO 2 I =1,ITOT READ (9) (FERT(J), J =1,7) FNH4 = FERT(2) *CONY *0.7777 $FNO3= FERT(3)*CONV *.2258 FUREA = FERT(4)*CONV.4466 $FCA = FERT(5) *CONY $FCO3 = FERT(7) *CONV FSO4 = FERT(6) *CONV C PRINT FERTILIZER APPLICATIONS PRINT 113, I, FERT( 1 ),FNH4,FNO3,FUREA,FCA,FSO4,FC03 REWIND 9 REWIND 10 PRINT 109 2 C PRINT ORGANIC APPLICATION DATES PRINT 114, (IORNAP(J),J= 1,JTOT) PRINT 115 DO 3 I= 1,JTOT READ (10) (OFERT(J),J =1,3) FORN = OFERT (3) *CONV* 0. 4 /OFERT (2) 3 PRINT ORGANIC APPLICATIONS PRINT 113, I,OFERT(1),OFERT(2),FORN REWIND 10 C PRINT COMPONENT HORIZON DEPTHS C PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT Page 82 PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 PRINT 106, PRINT 103 RETURN 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 (HOR(J),J =1,0) FORMAT(1H1 //,38X,10A8//) FORMAT(56X *CONTROL CARD SUMMARY * /57X *(BASIC PARAMETERS) * //35X = *,F5.1,/35X = *,I5,10X *XTRACT 1 *STARTING MONTH = *,I5/35X = *,I5,10X *CROP i *STARTING DAY 2 *RELATIVE STARTING DAY = *,I5,10X *UPTAKE(NO3) = *,F5.2,/35X = *,F5.2,/35X 3 *RELATIVE TERMIN DAY = *,I5,10X *UPTAKE(NH4) = *,F5.2,/35X = *,F5.1,* CM *7X, *CONVERG1 4 *SOIL SEGMENT SIZE = *,F5.3/35X = *,F5.2,* DAYS *5X *CONVERG2 5 *TIME INTERVAL SIZE = *,F5.1/35X 6 *NO. OF COMPONENT HRZNS =*,I5,10X *CHECK1 = *,F5.1/35X 7 *NO. OF TEMP HRZNS = *,I5,10X *CHECK2 *,I5,10X *YEAR = *,I5/35X 8 *ISTOP 9 *REDUCE = *,F5.0 / / //) FORMAT(55X *(I CONTROL PARAMETERS) * //35X *,I5/35X = *,I5,10X *IREADP 1 *IPRINT = *,I5/35X 2 *JPRINT = *,I5,10X *ITEST = *,I5/35X 3 *INK = *,I5,10X *IMASS *,I5/35X 4 *IRERUN = *,I5,10X *IPRINTI 5 *IPUNCH = *,I5,10X *IPRINTJ = *,I5 / / //) FORMAT(1H1) FORMAT( //15X *WEEKLY TEMPERATURE DATA *13X *HORIZON DEPTH(CM)* 1/46X,6(3X,F6.1)) FORMAT (20X,I3,2X *TEMPERATURE(DEG C) = *2X,6F9.1) FORMAT( / /10X *COMPONENT HORIZON OEPTHS(CM)* , 6X,6(3XF6.1)) FORMAT(10X *IRRIGATION WATER ANALYSIS (PPM) * /10X *NH4 *7X *NO3 *7X *CA *7 iX *NA *7X *MG *6X *HCO3 *7X *CL *7X *CO3 *7X *SO4 *) FORHAT(3X,9F10.2 //) 0 FORMAT( //) FORMAT(10X *IRRIGATION APPLICATION OATES * /8X,20I5) FORMAT( / /10X *FERTILIZER APPLICATION DATES * /8X,20I5) FORMAT( / /10X *FERTILIZER APPLICATIONS (UG) * /10X *DEPTH *5X *NH4 *5X *NO3* 15X *UREA *5X *CA *5X *SO4 *5X *CO3 *) FORMAT(2X,I5,7F8.1) FORMAT(10X *ORGANIC APPLICATION DATES * /8X,5I5) APPLICATIONS(UG) */10X *DEPTH *5X *G /N *5X *ORN *) FORMAT( / /10X *ORGANIC N N ENO SUBROUTINE CHK(L1,L2,L3,J, EXNH3, EXCA ,EXANA,EXAMG,DELN03,DELNH3,0EL 1ORGN,DELUREA) C C C THIS SUBROUTINE DETERMINES IF THE NITROGEN TRANSFORMATION AND/OR ION EXCHANGE SUBROUTINES NEED BE CALLED FOR THIS TIME STEP (BASED ON CRITERIA READ FROM DATA CARDS) COMMON /XXX /OELX,DELT,MS,WTART,BD(25 ),TEN(25 ),CHECK(25 ),MOISIN 1(25 ),CMH201(25 ),MOISOUT(25 ),AN03(25 ),ANH3(25 ),UREA(25 ),ORN 2(25 ),CA(25 ),ANA(25 ),AMG(25 ),HCO3(25 ),CL(25 ),CO3(25 ),SO4(25 3),E5(25 ),C5(25 ),SA5(25 ),XXS(25 ),GASO(25 ),AGSO(25 ),BNH4(25 ), 4EC(25 ),CN1(25 ),SAMT(25 ),RN(25 ),RC(25 ),TEM(25 ),CAL(25 ),Q,SRO 1P, XTRACT,SUMNO3,THOR(4),TO,IDAY,U (25),CH,CHI,IRERUN COMMON /XX2 /A1,A2,A3,X REAL MOISIN, MOISOUT DIMENSION X(7,25) L1 = L2 = L3 = 0 6 IF(ABS( EXNH3 ).LT.A1.AND.ABS(EXCA).LT.A1)1,2 IF( ABS( EXANA) .LT.A1.AND.ABS(EXAMG).LT.A1)3,2 ANH3(J)).LT.Ai)4,2 IF(ABS(X(2,J) CA(J)),LT.A1)5,2 IF(ABS(X(5,J) ANA(J)).LT.A1)6,2 IF(A8S(X(6,J) AMG(J)).LT.A1)7,2 IF(ABS(X(7,J) 7 L1 = 1 1 3 4 5 Page 83 PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT PRNT CHK GHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 8 IF( ABS( OELN03). LTA2.AND.ABS(DELNH3).LT.A2)8,9 IF( ABS( DELORGN). LT .A2.AND.ABS(DELUREA).LT.A2)10,9 10 11 12 13 IF(ABS(X(1,J) - ANO3(J)).LT.A2)11,9 IF(ABS(X(2,J) - ANH3(J)).LT.A2)12,9 IF(ABS(X(4,J) - ORN(J)).LT.A2)13,9 IF(ABS(X(3,J) -UREA(J)).LT.A2)14,9 14 L2 = 1 IF( ABS( MOISIN( J)). GT. A3 .0R.ABS(MOISOUT(J)).GT.A3)15,16 L3 = 1 X(1,J) = AN03(J) $X(2,J) = ANH3(J) 2 9 16 15 X(3,J) X(51J) X(7,J) RETURN END = = = UREA(J) $X(4,J) = ORN(J) $X(6,J) = ANA(J) CA(J) AMG(J) INTEGER FUNCTION DAY(K,M) L = 0 (1,2,3,4,5,6,7,8,9,10,11,12,13) M $ RETURN OAY =K -L $ RETURN DAY =K -L+31 $ RETURN DAY= K -L +62 $ RETURN OAY =K -L+90 $ RETURN DAY =K -L +121 $ RETURN OAY =K -L +151 $ RETURN DAY =K -L +182 $ RETURN DAY =K -L+212 $ RETURN DAY =K -L +243 $ RETURN DAY =K -L +274 $ RETURN DAY =K -L +304 S RETURN DAY =K -L +335 DAY =K -L+365 $ RETURN GO TO 12 1 2 3 4 5 6 7 8 9 10 11 13 END 12 1 2 3 4 5 6 7 8 9 10 11 SUBROUTINE THEDATE(K,L,SMONTH,K1) COMMON/YYY/ R,IDTE,MONTH INTEGER SMONTH,DAY JOAY = DAY(K,SMONTH) M = JOAY + L - K1 - 1 GO TO 12 IF(M.GE.1.AND.M.LE.31) GO TO 1 IF(M.GT.31.AND.M.LE.62) GO TO 2 IF(M.GT.62.ANO.M.LE.90) IF(M.GT.90.ANO.M.LE.121) GO TO 3 IF(M.GT.121.AND.M.LE.15i)GO TO 4 IF(M.GT.151.AND.M.LE.182)G0 TO 5 IF(M.GT.182.AND.M.LE.212)G0 TO 6 IF(M.GT.212.ANO.M.LE.243)G0 TO 7 IF(M.GT.243.AND.M.LE.274)G0 TO 8 IF(M.GT.274AND.M.L£.304)G0 TO 9 IF(M.GT.304.AND.M.LE.335)G0 TO 10 IF(M.GT.335.AND.M.LE.365)GO TO 11 $ MONTH =12 IDTE =M $ MONTH =1 IDTE =M -31 $ MONTH =2 IDTE =M -62 $ MONTH =3 IDTE =M -90 $ MONTH =4 IDTE =M -121 IDTE =M -151 $ MONTH =5 $ MONTH =6 IDTE =M -182 $ MONTH =7 IDTE =M -212 $ MONTH =8 IDTE =M -243 $ MONTH =9 IDTE =M -274 $ MONTH =10 IDTE =M -304 IDTE =M -335 $ MONTH =11 END SUBROUTINE IDAY (SMONTH,SDAY,MONTH,IDTE,JOAY,K) INTEGER SMONTH,SDAY,DAY .IDAY = DAY(SDAY,SMONTH) JJDAY = DAY(IDTE,MONTH) Page 84 $ á 1 $ $ $ $ $ $ $ $ $ RETURN RETURN RETURN RETURN RETURN RETURN RETURN RETURN RETURN RETURN RETURN RETURN CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK CHK 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 DAY DAY DAY 2 DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE THEDATE IDAY IDAY IDAY IDAY 3 4 5 6 7 8 9 10 li 12 13 14 15 16 17 18 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 2 3 4 5 JDAY = JJDAY i 2 C C C G C G JDAY + IF(JDAY.LE.0)1,2 JDAY = JDAY + 365 + K RETURN IDAY IDAY IDAY IDAY IDAY END SUBROUTINE UNITS1(J) UNITSI UNITS1 THIS SUBROUTINE CONVERTS UNITS FROM MEQ /L TO UG /SEGMENT, OR UNITSI UG /SEGMENT TO MEQ /L AT ENTRY POINT UNITS2 UNITS1 UNITS1 UNITSI UNITSI COMMON /XXX /DELX,DELT,MM,START,B0(25 ),TEN(25 ),CHECK(25 ),MOISIN UNITSI 1(25 ),CMH2O1(25 ),MOISOUT(25 ),AN03(25 ),ANH3(25 ),UREA(25 ),ORN 2(25 ),CÁ(25 ),ANA(25 ),AMG(25 ),HCO3(25 ),CL(25 ),CO3(25 ),SO4(25 UNITS1 3),E5(25 ),C5(25 ),SAS(25 ),XX5(25 ),CASO(25 ),AGSO(25 ),BNH4(25 ), UNITSI 4EC(25 ),CN1(25 ),SAMT(25 ),RN(25 ),RC(25 ),TEM(25 ),CAL(25 ),Q,CRO UNITSI UNITS1 1P UNITSI CONVERT FROM MEQ/LITER TO UG /SEGMENT UNITS1 ANH3(J) = ANH3(J) *CMH2O1(J) *14.0 UNITSI ANO3(J) = AN03(J) *CMH2O1(J) *14.0 UNITSI UREA(J) = UREA(J)*CMH 201(J) *28.0 UNITSI CA(J) = CA(J) *CMH2O1(J) *20.04 UNITS1 ANA(J) = ANA(J) *CMH2O1(J) *22.99 UNITSI AMG(J) = AMG(J) *CMH201(J) *12.16 UNITS1 UNITS1 HCO3(J) = HCO3(J) *CMH2O1(J) *61.0 UNITSI CO3(J) = CO3(J) *CMH2O1(J) *30.0 UNITSI CL(J) = CL(J) *CMH2O1(J) *35.46 SO4(J) = SO4(J) *CMH2O1(J)448.05 UNITSI UNITS1 ORN(J) = ORN(J)*80(J) *DELX SAMT(J) = SAMT(J) *9D(J) *DELX UNITS1 UNITSI RETURN ENTRY UNITS2 UNITS1 UNITSI UNITSI CONVERT FROM UG /SEGMENT TO MEQ /LITER ANH3(J) = ANH3(J) /(CMH2O1(J) *14.0) UNITSI ANO3(J) = AN03(J) /(CMH2O1(J) *14.0) UNITS1 UREA(J) = UREA(J) /(CMH2O1(J) *28.0) UNITS1 CA(J) = CA(J) /(CMH2O1(J) *20.04) UNITS1 ANA(J) = ANA(J) /(CMH2O1(J) *22.99) UNITSI AMG(J) = AMG(J) /(CMH2O1(J) *12.16) UNITS1 HCO3(J) = HCO3(J) /(CMH2O1(J) *61.0) UNITS1 CO3(J) = CO3(J) /(CMH2O1(J) *30.0) UNITSI CL(J) = CL(J) /(CMH2O1(J) *35.46) UNITS1 SO4(J) = SO4(J) /(CMH2O1(J) *48.05) UNITS1 ORN(J) =ORN(J) /BO(J) /DELX UNITSI RETURN UNITS1 UNITS1 END SUBROUTINE OUTPT(K) OUTPT OUTPT THIS SUBROUTINE WRITES PREDICTED TOTAL AND DELTA AMOUNTS FOR THE OUTPT OUTPT COMPONENTS ANO VOLUMES ON TAPE2 (UNITS ARE EXPRESSED IN UG /UNIT AND ML /UNIT AREA). OUTPT OUTPT OUTPT DIMENSION AMT(10),AMT1(10),DEL(10) OUTPT OUTPT INTEGER Q,O,START,C ROP,TO OUTPT REAL MOISOUT OUTPT OUTPT COMMON /SABLE /SUMS(3) OUTPT COMMON /XXX /DELX,DELT,MS,WTART,BD(25 ),TEN(25 ),CHECK(25 ),MOISIN OUTPT 1(25 ),CMH2O1(25 ),MOISOUT(25 ),AN03(25 ),ANH3(25 ),UREA(25 ),ORN OUTPT 2(25 ),Có(25 ),ANA(25 ),AMG(25 ),HCO3(25 ),CL(25 ),CO3(25 ),SO4(25 OUTPT 3),E5(25 ),C5(25 ),SA5(25 ),XX5(25 ),CASO(25 ),AGS0(25 ),BNH4(25 ), OUTPT 4EC(25),CN1(25 ),SAMT(25 ),_R_N(25 ),RC(25 ),TEM(25 ),CAL(25 ), Q,CRO OUTPT K CAREA Page 85 6 7 8 9 10 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 _15_ 1P, XTRACT, SUMN03, THOR (4),TO,IDAY,U(25),CH,CH1,IRERUN C ESTABLISH STATEMENT FUNCTION SUBA(X,Y) = X *Y IF(K.EQ.1) 1,2 C ZERO INITIAL VALUES SUMOUT = SUMOUTI = 0.0 00 3 I =1,10 AMT(I) = AMT1(I) = 0.0 1 3 GO TO 2 5 Y = Z = CMH2O1(Q) MOISOUT(Q) Y = Z/Y IF(Y.GT.1) C C Y =1.0 SUM THE COMPONENTS AMT(1) = SUMS(1) AMT(2) = SUMS(2) AMT(3) = SUMS(3) AMT(4) = AMT(4) + SUBA(CA(Q),Y) AMT(5) = AMT(5) + SUBA(ANA(Q),Y) AMT(6) = AMT(6) + SUBA(A)!G(Q),Y) AMT(7) = AMT(7) + SUBA(HCO3(Q),Y) AMT(8) = AMT(8) + SUBA(CL(Q),Y) AMT(9) = AMT(9) + SUBA(CO3(Q),Y) AMT(10) = AMT(10) + SUBA(SO4(Q),Y) SUM THE VOLUMES OUT SUMOUT = SUMOUT + MOISOUT(Q) IF(K.EQ.2)4,5 C 4 6 COMPUTE DELTA VALUES FOR COMPONENTS 00 6 1 =1,10 DEL(I) = AMT(I) - AMT1(I) C COMPUTE DELTA VALUE FOR VOLUME OUT DELN = SUMOUT - SUMOUTI C WRITE SUMMATIONS AND DELTA VALUES ON TAPEZ WRITE (2,100) SUMOUT,OELN,(AMT(I),DEL(I),I=i,10) C RESET VALUES FOR DELTA DETERMINATIONS 00 7 I =1,10 AMT1(I) = AMT(I) SUMOUT1 = SUMOUT 7 5 K =3 C RETURN TO MAIN PROGRAM RETURN 100 FORMAT(IX,12E10.3) END Page 86 OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT OUTPT 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 APPENDIX B Sample Card Inputs Page 87 CARD INPUTS FOR MOISTURE FLOW PROGRAM 1 1 1 1 5 2. WATER APPLICATIONS 01/06 AMT= WATER APPLICATIONS 01/15 AMT= WATER APPLICATIONS 01/21 AMT= WATER APPLICATIONS 02/06 AMT= WATER APPLICATIONS 02/15 AMT= WATER APPLICATIONS 02/21 AMT= WATER APPLICATIONS 03/06 AMT= 03/15 AMT= WATER APPLICATIONS WATER APPLICATIONS 03/21 AMT= WATER APPLICATIONS 04/15 AMT= WATER APPLICATIONS 05/15 AMT= WATER APPLICATIONS 06/15 AMT= WATER APPLICATIONS 07/01 AMT= WATER APPLICATIONS 07/15 AMT= WATER APPLICATIONS 08/10 AMT= WATER APPLICATIONS 09/15 AMT= WATER APPLICATIONS 10/15 AMT= WATER APPLICATIONS 11/06 AMT= WATER APPLICATIONS 11/21 AMT= WATER APPLICATIONS 12/01 AMT= WATER APPLICATIONS 12/06 AMT= WATER APPLICATIONS 12/21 AMT= 152. CM. 1 PANOCHE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE INITIAL MOISTURE CONTENT OF NODE 3.31 0.25 42,4 47.0 3.54 0.39 47.0 3.65 0.79 0.99 48,1 3.17 46.0 4.04 1.17 4.31 1.38 58.8 4.47 2.08 55,8 4.47 62.5 1.74 66.6 4.84 0.99 i. i 3 100 22 5. .38 .20 .07 .07 SOURCE =R SOURCE =I SOURCE =R SOURCE =R SOURCE =I SOURCE =R SOURCE =R SOURCE =I SOURCE =R SOURCE =I SOURCE =I SOURCE =I SOURCE =I SOURCE =I SOURCE =I SOURCE =I SOURCE =I SOURCE =R SOURCE =R SOURCE =I SOURCE =R SOURCE =R .61 .30 .91 .91 3.35 .61 .61 7.62 .30 4.88 8.44 12.80 7.92 7.92 11.58 6.71 5.18 .30 .61 .91 ,61 .61 IF CC =1, IF CC =1, 3 IF CC =1, 4 IF CC =1, 5 IF CC =1, 6 IF CC =1, 7 IF CC =1, 8 IF CC =1, 9 IF CC =1, 10 IF CC =1, 11 IF CC =1, 12 IF CC =1, 13 IF CC =i, 14 IF CC =1, 15 IF CC =1, 16 IF CC =1, 17 IF CC =1, 18 IF CC =1, 19 IF CC =1, 20 IF CC =1, 21 IF CC=1, 22 IF CC =1, 23 IF CC =1, 24 IF CC =1, 25 IF CC =1, 26 IF CC=1, 27 IF CC =1, 28 IF CC =1, 29 IF CC =1, 30 IF CC =1, 31 IF CC =1, i 2 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 Page 88 .21220 .21568 .21897 .22210 .22511 .22803 .23091 .23377 .23666 .23961 .24265 .24583 .24919 .25276 .25659 .26073 .26523 .27012 .27548 .28136 .28782 .29494 .30284 .31162 .32146 .33259 .34532 .36014 .36528 .37165 .38000 JAN -1 JAN -2 FEB -1 FEB -2 MAR -i MAR -2 APR -1 APR -2 MAY -1 73.9 71.9 73.8 79.1 82.6 81.9 77.6 75.0 75.0 65.0 65.0 55.0 55.0 45.0 41.6 0.30 0.35 0.48 CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE CONSUMPTIVE USE USE USE USE USE USE USE USE USE USE USE USE USE USE USE USE USE USE USE USE USE USE USE USE 5.16 5.03 5.03 4.94 5.27 4.63 4.94 4.22 4.22 3.80 4.06 3.42 3.42 3.22 3.43 0.24 0.26 0.20 (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) (INCHES) 0.99 0.99 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.12 0.12 0,19 0.16 0.13 0.08 0.08 0.11 0.11 0.32 0.32 0.70 0.70 1.60 1.61 2.32 2.43 3.50 3.70 2.70 2.00 1.10 1.00 0.01 0.01 0.03 0.03 0.04 0.04 FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR 0.00 0.14 0.74 1.29 1.67 1.34 0.86 1.51 0.18 0.00 0.00 0.00 0.00 0,00 0.00 0.13 0.11 0.10 15 DAY 15 DAY 15 DAY 15 DAY 15 DAY 15 DAY 15 DAY 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 15 DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY DAY 0.06 0.05 0.00 0.08 0.07 0.09 PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS PERIODS Page 89 FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR FOR COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE COMPOSITE CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP CROP MAY -2 JUN -1 JUN -2 JUL -1 JUL -2 AUG -1 AUG -2 SEP -i SEP -2 OCT -1 OCT -2 NOV -1 NOV -2 DEC -i DEC -2 KP- BARLEY KP -MILO KP -AVG. JAN -1 JAN -2 FEB -1 FEB -2 MAR -i MAR -2 APR -1 APR -2 MAY -1 MAY -2 JUN -1 JUN -2 JUL -1 JUL -2 AUG -1 AUG-2 SEP -1 SEP -2 OCT -1 OCT -2 NOV -1 NOV -2 DEC -i DEC -2 CARD INPUTS FOR BIOLOGICAL- CHEMICAL PROGRAM SAN LOUIS DRAIN RUN NO. 4 HALF FERTILIZER APPLICATION 5. 5. 0.0 0. ;. 1. 1. .11.E -3 .1 15 53 5 3 3 0 0 10 10 1 1 10 01 02 03 04 05 06 07 08 09 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 1 10 1 20 30 46 152 92 61 8.89 8.89 8.89 8.89 10.00 10.00 10.00 10.00 12.22 12.22 12.22 12.22 12.22 15.56 15.56 15,56 15.56 18.89 18.89 18.89 18.89 22,22 22.22 22.22 22,22 22.22 24,044 24.44 24,44 24.44 23.33 23.33 23.33 23.33 23.33 21.11 21.11 21.11 21.11 16.67 16.67 16.67 16.67 12,22 12.22 12.22 12.22 12.22 49 10.00 50 10.00 51 10.00 52 10.00 53 10.00 .0035.0074 19.5 19.5 19.5 19.5 1 122 10.00 10.00 10.00 10.00 11.11 11.11 11.11 11.11 12.78 12.78 12.78 12.78 12.78 16.11 16.11 16.11 16.11 18.89 18.89 18.89 18.89 20.56 20.56 20.56 20.56 20.56 22.78 22.78 22.78 22.78 22.22 22.22 22.22 22.22 22.22 21.11 21.11 21.11 21.11 17.78 17.78 17.78 17.78 14.44 14.44 14.44 14.44 14.44 11.67 11.67 11,67 11.67 11,67 .97 1.63 0.0 0.1 0.1 0.1 152 16.67 16.67 16.67 16.67 15.56 15.56 15.56 15.56 16,67 16.67 16.67 16.67 16.67 17.78 17.78 17,78 17.78 18.89 1889 18.89 18,89 20006 20.06 20.06 20.06 20.06 21.67 21.67 21,67 21.67 22.22 22.22 22.22 22.22 22.22 21.11 21.11 21.11 21.11 20.06 20.06 20.06 20,06 18,89 18.89 18.89 18.89 18.89 17.78 17.78 17.78 17.78 17.78 .86 1.31 1.37 0,1 0.1 0.1 0.1 .02 300 300 300 300 .76 Page 90 0 1 1 1 19.5 19.5 19,5 19.5 19.5 19.5 19,5 029 .60 .015 1.06 .011 1.52 .012 1.58 .013 4.16 7 74 227 1 37.1 52.6 71.1 75,0 99,4 32.5 34.8 35.3 35.4 39.0 27.4 29.5 30.0 31.2 88.8 1.0 1.0 1.0 1.0 1.0 135 166 182 196 222 258 288 335 0,0 12,5 76,5 0.0 18,3 84,8 0.0 24,2103,7 105 166 135 0 0 2,75 10.6 7.65 10.6 5.30 6.30 0 22 23 24 6.3 10.2 18.3 30.2 42.9 258 0.1 0.1 0.0 0.0 0.0 196 2.0 1.8 1.7 1.1 222 46 15 21 2.3 1.5 2.2 3,8 0 0 14 15 16 17 18 19 20 2.2 15 0 10 11 12 13 0.0 11.9 31.7 0.0 10.0 53.4 0 0 02 03 04 05 06 07 08 09 0.1 0.1 0.1 0.1 0.1 0.1 0.1 12 0 01 0.1 0.1 0.1 0.1 0.1 0,1 0.1 30 2000 .48 74 15.2 .20 0,30 0.30 0.45 0.45 1,30 1.30 2.80 2.80 6.40 6.40 9.20 9.60 14.00 105 5.5 .13 300 300 300 300 300 300 300 .10 14.6(? 10.00 8.60 4,30 4.00 0.10 0,0 0.10 0.10 0,20 0.10 Page 91 .09 1.3 2135 1.3 1585 1.3 1278 1.3 1175 1,3 1132 5 S S 5 5 APPENDIX C Sample Printed Outputs Page 93 PRINTED OUTPUT FROM MOISTURE FLOW PROGRAM PARAMETERS, CONSTANTS, ANO INITIAL CONDITIONS USED IN THIS REPORT. DIFFUSIVITY ANO CONDUCTIVITY RELATIONSHIPS MUST RE INSERTED INTO SOURCE DECK. NOTE RUN PARAMETERS, ANO ROUNOARY CONDITIONS. TRC YEAR CROP MM DPI LL AA Pn CC 1 1 1 WATER APPLICATION 6 DAY NUMPER DAY NUMPER 15 NUMBER 21 DAY DAY NUMPER 37 46 DAY NUMPER DAY NUMPER 52 DAY NUMPFR 65 DAY NUMBER 74 80 DAY NUMPER DAY NUMPER 105 DAY NUMPER 135 OAT. NUMPER 166 DAY NUMPER 182 DAY NUMPER 196 DAY NUMBER 222 DAY NUNPER 258 DAY NUMPER 788 DAY NUMPER 310 DAY NUMBER 325 DAY NUMPER 335 DAY NUMPER 340 DAY NUMPER 355 1 5 .38 .20 M 100 3 1 APPS DELx 22 5.00 DAYS, DATES, ANO AMOUNTS. .61 CM. AMOUNT= GAZE if 6 .30 CM. AMOUNT= DATE 1/15 .91 CM. AMOUNT= 1/21 DATE AMOUNT= .91 CM. DATE 2/ 6 AMOUNT= 3.35 CM. DATE 2/15 AMOUNT= .61 CM. GATE 2/21 .61 CM. AMOUNT= PATE 3/ 6 7.62 CM. AMOUNT= OATE 3/15 AMOUNT= .30 CM. DATE 3/21 AMOUNT= 4.88 CM. DATE 4/15 AMOUNT= 8.84 CM. DATE 5/15 HATE 6/i5 AMOUNT= 12.80 CM. AMOUNT= 7.92 CM. DATE 7f 1 AMOUNT= 7.92 CM. PATE 7f15 AMOUNT= 11.58 CM. DATE 8/10 'ATE AMOUNT= 6.71 CM. 1/15 AMOUNT= 5.18 CM. DATE 10115 AMOUNT= .30 CM. RAT=_ 11/ 6 .61 CM. AMOUNT= PATE 11/21 AMOUNT= .91 CM. DATE 12/ 1 .61 CM. AMOUNT= OATE 12/ 6 .61 CM. AMOUNT= DATE 12/21 TS TM .38 .20 SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE SOURCE TO .07 SM .07 R = I = = R = R = I = R = R = = = I R I = I = I = I = I = I = I = = I R = R = I = R = R SOIL IDENTIFICATION AND HORIZON DEPTHS. DEPTH= 152.0 IOFNTIFICATION= PANOCHE . THETA INITIAL SOIL MOISTURE CONDITIONS. .218970 .215680 .212200 .249190 .245810 .242650 .302840 .294140 .287820 .380000 READ ACROSS THEN DOWN. .230910 .228030 .225110 .265230 .260730 .256590 .345320 .332590 .321460 AT EACH DEPTH NODE, .222100 .252760 .311620 CONSUMPTIVE USE DATA. BLANEY- CRIDDLE DATA TO GET U SEMI -MONTH PCT -HV K- CROP -1 K- CROP -2 AVG -TEMP 1 2 3 4 5 6 7 8 g 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 42.4 47.0 47.3 48.1 46.0 58.1 55.8 62.5 66.6 73.9 71.9 73.8 79.1 82.6 81.9 77.6 75.0 75.0 65.0 65.0 55.0 55.0 45.0 41.6 3.31 3.54 3.65 3.17 4.04 4.31 4.47 4.47 4.84 5.16 5.03 5.03 4.94 5.27 4.63 4.94 4.22 4.22 3.80 4.06 3.42 3.42 3.22 3.43 .25 .39 .79 .99 1.17 1.38 2.08 1.74 .99 .99 .99 0.00 1.00 0.00 0.00 0.00 0.00 1.110 0.00 0.00 0.00 0.00 .12 .12 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 .14 .74 1.29 1.67 1.34 .233770 .270120 .360140 .236660 .275480 .365280 U IF CROP =3 ONLY. (CM /15 DAYS) .20 .20 .28 .28 .81 .81 1.78 1.78 4.06 4.09 5.89 6.17 8.89 9.40 6.86 5.08 .86 2.79 2.54 .03 .03 .08 .08 1.51 .18 0.00 0.00 0.00 0.00 0.00 0.00 .10 .10 PERCENT OF ROOTS IN FACH OG TOP 6 FEET. CROP =1 .300 .240 .190 .130 .080 .060 PERCENT OF ROOTS IN EACH OF TOP 6 FEET. CROP =2 .350 .260 .160 .110 .070 .050 PERCENT OF ROOTS IN EACH OF TOP 6 FEET. CROP =3 .480 .200 .130 .100 .090 -0.000 Page 94 .239610 .281360 .371650 DAILY OUTPUT, INCLUDING THETA AT EACH DEPTH NODE MONTH YT IDTE 1.003 1 1 .213607 .211192 .216853 .240999 .244296 .247778 .294633 .287415 .302604 .380900 II 1 DAILY OUTPUT, INCLUDING THETA AT EACH MONTH XT 2 1.000 1 .211821 .208468 .242999 .239593 .287399 .294390 .380030 II DAILY OUTPUT, DAILY OUTPUT, THETA AT EACH DEPTH NODE MONTH IDTE 3 1.000 1 3 .206967 .210266 .213448 .238396 .241899 .245597 .294192 .286840 .302276 .380001 XT INCLUDING THETA .219967 .251484 .311455 OPTION BB = 1. CHECK ETS ET OIF .1431 -.0000 .3131 -.1563 .222985 .225944 .228878 .255453 .259730 .264358 .321353 .332519 .345282 IF PRINT OPTION 9B CHECK CL .7486 .216546 .249526 .311220 . XT MCNTH 4 1.000 1 .274485 .236493 .286447 .380000 .234800 .274864 .365271 .237846 .280852 .371642 .233204 .274370 .365262 .236340 .280452 .371637 .231834 .273963 .365256 .235052 .280124 .371634 .230651 .273625 .365250 .233944 .279852 .371630 .229623 .273341 .365245 .232984 .279624 .371628 I 100 .230149 .268788 .360108 1. ETS ET DIF -.0000 .0394 -.4010 .3616 .222609 .225638 .219589 .263063 .253721 .258220 .332419 .345227 .321192 .208901 .240959 .294028 NOCE IF PRINT OPTION 8B = 1. IDTE CHECK ETS 0IF CL ET 4 .4293 -.0000 .3525 -.4982 .4456 .212060 .218211 .221261 .215154 .224333 .244748 .257643 .262572 .248769 .253055 .302155 .311134 .321133 .332382 .345207 DAILY OUTPUT, INCLUDING THETA AT EACH DEPTH NODE IF PAINT OPTION 88 = MONTH II XT IOTE CHECK CL 5 I 101 .231823 .269385 .360120 I 100 .228708 .268295 .360099 AT EACH DEPTH II .205649 .2373+9 .286625 .380009 CL .1381 DEPTH NOCE IF PRINT OPTION 88 = 1. IOTE CL CHECK ETS ET DIF 2 .2527 .2620 -.0000 .0262 -.2883 .215132 .224157 .227140 .218136 .221167 .246596 .250420 .263650 .254510 .258906 .302423 .332463 .345252 .311325 .321263 INCLUDING IT IF PRINT 1.100 5 1 .207698 .740152 .293891 .210837 .244021 .302054 .4974 .213929 .248123 .311062 .227458 .267883 .360091 1. ETS ET DIF .5167 -.0000 .3656 -.5823 .217000 .220078 .223192 .257155 .252489 .262157 .332352 .321084 .345190 Page 95 I 100 I 100 .226369 .267537 .360084 PRINTED OUTPUT FROM BIOLOGICAL- CHEMICAL PROGRAM SAN LOUIS GRAIN RUN NO. 4 HALF FERTILIZER APPLICATION CONTROL CARD SUMMARY tBASIC PARAMETERS) = 1 STARTING MONTH = 1 STARTING DAY RELATIVE STARTING DAY = 1 10 RELATIVE TERMIN DAY = 15.0 CM SOIL SEGMENT SIZE = .1O OAYS TIME INTERVAL SIZE 5 NO. OF COMPONENT HRZNS= 3 = NO. OF TEMP HRZNS = = ISTOP REDUCE (I 1 = 1.0 = = 3 1.00 = 0.00 .10 9 = .001 = 1.0 = = 5.0 1 5. -0 CONTROL PARAMETERS) IREADP ITEST IMASS IPRINTI IPRINTJ IPRINT JPRINT INK IRERUN IPUNCH XTRACT CROP UPTAKEtNO3) UPTAKEtNH4) CONVERG1 CONVERG2 CHECK1 CHECK2 YEAR = 0 o 10 1 1 INITIAL SOIL ANALYSEStMEGIL OF SOIL EXTRACT) -- tORG=UG /GM OF SOIL) HZN 1 2 3 4 S NH3 .029 .015 .011 .012 .013 NO3 .600 1.060 1.520 1,580 4.160 UREA 0.000 0.000 0.000 0.000 0.000 SEG NH3 NO3 2 7.917 7.917 4.095 4.095 3.003 3.003 3.276 3.276 3.549 3.549 163.800 163.800 289.380 289.380 414.960 414.960 431.340 431.340 1135.680 1135.680 3 4 S 6 7 8 9 10 11 CA NA MG 11.900 10.000 12.500 18.300 24.200 31.700 53.400 76.500 84.800 103.700 2.200 1.500 2.200 3.800 5.500 1278.000 1175.000 1132.000 TRANSFORMED SOIL ANALYSES(UG /SEGMENT UREA 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORG 2135.000 1585.000 HCO3 2.300 2.000 1.800 1.700 1.100 6.300 10.200 18.300 30.200 42.900 HCO3 2735.850 2735.850 2379.000 2379.000 2141.100 2141.100 2022.150 2022.150 1308.450 1308.450 4356.261 4356.261 7052.994 7052.994 12653.901 12653.901 20882.394 20882.394 29664.063 29664.063 CL CO3 .100 .100 0.000 0.000 SO4 0.000 97.100 52.600 71.100 75.000 89.400 CO3 58.500 58.500 58.500 58.500 0.000 0.000 0.000 0.000 0.000 0.000 34751.772 34761.772 49284.885 49284.885 66618.922 66618.922 70273.125 70273.125 83765.565 83765.565 OF SOIL) ORG 41632.500 41632.500 30907.500 30907.500 24921.000 24921:000 22912.500 22912.500 22074.000 22074.000 CA NA MG 4650.282 4650.282 3907.800 3907.800 4884.750 4884.750 7151.274 7151.274 9456.876 9456.876 14211.268 14211.268 23939.487 23939.487 34295.332 34295.332 38016.264 38016,264 46489,228 46489.228 521.664 521.664 355.680 355.680 521.664 521.664 901.056 901.056 1304.160 1304.160 Page 96 CL SO4 WEEKLY TEMPERATURE DATA 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 3H 39 40 41 42 43 44 45 4h 47 49 49 50 51 52 53 TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATUREIDEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPFRATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPF,RATURE(DEG TEMPERATUREfDEG TEMPERATUREfDEG TEMPERATUREfDEG TEMPERATURE(DEG TEMPFRATURE(DEG TEMPERATURE(DEG TEMPERATUREfDEG TEMPFRATURE(DEG TEMPFRATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPFRATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(OEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPFRATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPFRATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPERATUREfDEG TEMPERATURE(DEG TEMPERATUREfDEG TEMPERATURE(DEG TEMPERATURE(DEG TEMPFRATURE(DEG HORIZON DEPTH(CM) 46.0 20.0 152.0 C)= C)= C)= C)= C)= C)= C)= C>= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C): C)= C)= C)= C)= C)= C)= C)= C)= C)= C)= C1= C)= C)= C)= C)= C)= C)= C)= C)= 8.9 8.9 0.9 8,9 10.0 10.0 10.0 10.0 12.2 12.2 12.2 1262 12.2 15.6 15.6 15.6 15.6 18.9 18.9 19.9 18.9 22.2 22.2 22. 2 22.2 22.2 24.4 24.4 24.4 24.4 23.3 23.3 23,3 23.3 23.3 21.1 21.1 21.1 21.1 16.7 16.7 16.7 16.7 12.2 12.2 12.2 12.2 12.2 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 10.0 11.1 11.1 11.1 11.1 12.8 12.8 12.8 12.8 12.8 16.1 16.1 16.1 16.1 18.9 18.9 19.9 18.9 20.6 20.6 20.6 20.6 20.6 22.8 22.8 22.8 22.8 22.2 22.2 22.2 22.2 22.2 21.1 21.1 2101 21.1 17.8 17.8 17.8 17.8 14.4 14.4 14.4 14.4 14.4 11.7 11.7 11.7 11.7 11.7 16.7 16.7 16.7 16.7 15.6 15.6 15.6 15.6 16.7 16.7 16.7 16.7 16.7 17.8 17.8 17.8 17.8 18.9 18.9 18.9 19.9 20.1 20.1 20.1 20.1 20.1 21.7 21.7 21.7 21.7 22.2 22.2 2 2.2 22.2 22.2 21.1 21.1 21.1 21.1 20.1 20.1 20.1 20.1 18.9 18.9 18.9 19.9 18.9 17.8 17.8 17.8 17.8 17.8 Page 97 IRRIGATION WATER ANALYSIS(PPM) NH4 NO3 CA NA .05 .10 19.44 37.47 IRRIGATION APPLICATION DATES 74 46 15 135 105 182 166 HCO3 79.91 MG 10.46 196 222 CL 48.58 SO4 .60 36.52 335 288 258 CO3 FERTILIZER APPLICATION DATES 74 135 105 196 166 222 258 FERTILIZER APPLICATIONS(UG) UREA NO3 NH4 DEPTH 6 0.0 0.0 0.0 0.0 0.0 -0.0 7 -0.0 1 2 3 4 5 0.0 24.0 92.5 66.8 92.5 46.3 55.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0 76.2 0.0 0.0 0.0 0.0 0.0 0.0 CA 0.0 0.0 0.0 (1.0 0.0 0.0 0.0 CO3 0.0 0.0 0.0 SO4 0.0 0.0 0.0 0.0 0.0 0.0 0.0 no 0.0 0.0 n.0 ORGANIC -N APPLICATION DATES 227 ORGANIC DEPTH 15.0 1 N APPLICATIONS(UG) C/N 30.0 ORN 299.2 30.0 COMPONENT HORIZON DEPTHSICM) 92.0 61.0 122.0 152.0 PLANT NITROGEN UPTAKE DATA INPUT FROM CARDS ROOT DISTRIHUTION 35.5 35.5 CM 0 61.0 CM .20 .48 61.0 - 91.5 CM .13 91.5 + 122 CM .ln TOTAL PLANT UPTAKE OF NITROGEN(UG /15 DAYS) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 3.37 3.37 5.05 5.05 14.59 14.59 31.42 31.42 71.82 71.82 103.24 107.73 157.10 163.83 112.21 96.50 48.25 44.89 1.12 0.00 1.12 1.12 2.24 1.12 Page 98 153 CM 122 .09 153 CM -0.00 SUMMARY OF NITROGEN BALANCE FOR SYSTEM INITIAL NITROGEN CONTENT = .280200E +05 UG 0. TOTAL -N ADDED TO SYSTEM = UG = FROM SYSTEM .588089E +q2 UG TOTAL -N LEACHED TOTAL -N UPTAKE BY PLANTS = .280748E+00 UG TOTAL INPUT - TOTAL OUTPUT FOR N = -.590297E +02 CHANGE IN N STORAGE SINCE START OF RUN = -.590297E +02 TOTAL -N UPTAKE BY PLANTS(ATTEMPTED) = UG UG .220748E +00 UG DAY= TIME_ INTERVAL= 10 10 PREDICTED AMOUNTS(UG /SEGMENT OF SOIL)-- (SEGVOL =CC WATER /SEG SOIL) SEG NH3 n!03 2 3 .330 .585 .583 138.771 206.347 277.867 284.809 355,359 389.616 406.515 412,544 850.529 1068.931 4 5 6 7 8 9 10 11 3.854 4.337 4.867 5,673 5.852 3.411 3.874 UREA 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ORI) CA NA MG 3331.116 3331.176 2473.194 2470.311 1992.067 1992.061 1831.596 1831.595 1764.259 1764.194 7354.232 7131.126 6712.354 6566.516 6498.992 6488.688 6832.366 7014.843 7239.611 7336.926 8498.387 12879.167 19815.098 23001.483 29982.601 33306.300 36362.157 37648.203 43025.682 45687,954 770.223 793.152 616.708 594.577 687.911 693.118 866.063 890.083 1031.582 1052.608 SUMMARY OF NITROGEN BALANCE FOR SYSTEM INITIAL NITROGEN CONTENT = .280200E+05 U0 UG TOTAL -N ADDED TO SYSTEM = O. .576270E +03 UG TOTAL -N LEACHED FROM SYSTEM = PLANTS UG = .220748E +01 TOTAL -N UPTAKE BY -.578477E +03 TOTAL INPUT - TOTAL OUTPUT FOR N = CHANGE IN N STORAGE SINCE START OF RUN _ -.578477E +03 TOTAL -N UPTAKE BY PLANTS(ATTEMPTED) = UG UG .220748E +01 UG Page 99 HCO3 1636.079 2479.418 2481.198 2407.431 2241.625 2164.014 2073.614 2033.740 1597.183 1375.567 CL 2605.108 3947.947 5903.265 6792.240 10360.982 12123.914 17489,728 20100.826 26008.894 28825.785 SO4 33564.266 39762.954 49898,539 54974.606 65124.061 69767.130 70469.308 70?15.117 .010 74857.791 .001 77097.161 CO3 34,984 53.017 57.618 58.393 23.506 5,482 .882 .107 ENH4 4,277 5.000 5.912 33.8]6 35.613 35.952 35.788 35,629 20.887 22.434 5EGVOL 19.500 19.500 19.500 19.500 19.500 19.500 19.500 19.500 19.500 19.500 References Cited ALEXANDER, M. 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