About the Cover: UA plant scientists

Dr. Douglas Bailey (pictured) and

Dr. William` Miller are grooming this flowering African vine for the American floral market.

Domesticating the Queen of Sheba plant is just one of many projects that UA agricultural researchers pursue in an effort to insure our food and fiber needs, manage our natural resources and improve our quality of life. (Photo by L. G. Ketchum)


Volume 38, Number 1




Landscape & Water






Food Technology.



Renewable Natural



Crop Protection



Economics 25



Family and





Animal Science... 30














On March 2, 1887, President Grover

Cleveland signed into law the Hatch Act of

1887. This landmark legislation created

State Agricultural Experiment Stations in each Land -Grant University in the United

States. It built a system of research that provided farmers and ranchers with the scientific knowledge that led the American agricultural revolution. It has allowed American agriculture to maintain a competitive

edge in world agriculture and the best

quality food at reasonable prices. In short, the Hatch Act established a system that has allowed one agricultural producer to supply food and fiber for an additional 80 persons.

They, in turn, have enriched our lives in so many ways through the multitude of goods and services that characterize this country.

A century later in 1987 we look back at the tremendous impact the Hatch Act has had on the lives of each of us. The century of progress has been unparalleled in the development of the world. Its significance has been recognized internationally until today it is emulated in many other countries.

Indeed, this year marks an anniversary and we note with pride the accomplishments of the past century. We have inherited a legacy of accomplishment, comfort and adequacy as we look forward to the next century.

What are some of the accomplishments of the Arizona Agricultural Experiment

Station? They are many but in mentioning only a few I would have to remember:

The release of Pima ELS cotton.

The discovery that fluoride played a role in the development of teeth.

The release of the first barley variety adapted to grow in ocean water.

Crop varieties adapted to Arizona conditions of high temperature and low humidity.

The role of salt in limiting intake of feed in cattle.

The value of environmental control in animal production.

On October 14, 1987 the new Maricopa

Agricultural Center will be dedicated.

You are invited to participate in this gala event. This activity will also commemorate the centennial of the Hatch Act.

Dr. L.W. Dewhirst

Associate Dean,

College of Agriculture and

Director Agricultural Experiment Station

(above) Experiment Station Director Dr. L. W.

Dewhirst has been the guiding force behind the UA's Maricopa Agricultural Center now under construction near Casa Grande. Dedication ceremonies for the 2,100 acre research farm are scheduled for

October 14, 1987




A microscope equipped with a television camera allows plant scientists to see a "big picture" of root cap cells.

Improving Alfalfa Genetically

In Arizona the economic value of alfalfa hay has been estimated at 100 million dollars, making-it the second most valuable crop in the state. Forages of all types provide 60 to 80 percent of the feed units consumed by ruminant animals. In addition, forages make a significant contribution to soil fertility maintenance when used in rotation in cropping systems. Improvements in forages, particularly alfalfa, including those which would allow the expansion into marginal lands by developing stress tolerant types, could contribute significantly to the farm economy of the state.

Wild relatives of cultivated plant species have frequently been used to improve the cultivated species. Various wild species related to alfalfa that are salt- and drought- tolerant have been identified; however, a major deterrent to the transfer of these economically important traits is the inability to form hybrids between alfalfa and the wild species.

Current research efforts have identified tissue culture techniques for recovering hybrids between alfalfa and related stress -tolerant species. The method consists of removing the hybrid embryo following fertilization and before it aborts, and culturing the embryo in the laboratory on a medium containing all essential nutrients. An alternative tissue culture method involves fusing cells of alfalfa and the related species followed by culturing the hybrid cells in the laboratory. Subsequently, appropriate manipulation of the tissue culture medium results in the production of hybrid plants. The new hybrids will be evaluated for stress tolerance.

Additional research efforts are directed toward manipulating the alfalfa chromosome complement to determine if an increased yield can be realized. The chromosome complement of cultivated alfalfa consists of four complete sets of eight chromosomes per set. Our tissue culture methods for producing new hybrids allows the production of plants consisting of six complete sets of eight chromosomes. These plants have the normal alfalfa chromosome complement plus two sets of chromosomes from a wild relative. Preliminary evalua-

tions indicate these plants may yield more than normal alfalfa.

Interspecific hybridization and chromosome manipulation research with alfalfa complements our breeding work using the conventional plant breeding techniques of hybridization and selection. In this part of our program, we are working to develop improved screening and selection procedures to allow for the eventual development of high yielding, stress -tolerant alfalfa varieties for the


Dr. T.J. McCoy

Dr. S.E. Smith

Department of Plant Sciences

Plants That Make Their

Own Fertilizer

Currently, mineral fertilizers are produced using costly, energy- intensive, large scale chemical processing technology. Biotechnology offers an alternative approach that uses something called bioconversion.

In the bioconversion process, raw materials are placed in the environment with the living organism and these materials are converted to the desired products by that organism via enzyme catalyzed reactions. Enzyme catalyzed reactions are many times more efficient than the chemical process technology.

Nitrogen fixation is a fairly common bioconversion process. In this system, bacteria living in association with plant roots convert atmospheric nitrogen gas to ionic forms of nitrogen useful as plant nutrients. Phosphorus, the second most important plant nutrient, must also be converted to an ionic form before it is available for plant growth. Just as with nitrogen gas, mineral and organic phosphorus compounds may be present in large quantities in the soil. Up to a ton or more of these compounds may exist in the top six inches of an acre of soil but they are unavailable as a fertilizer.

Recently workers in the Plant Sciences

Department have discovered that plants can respond to phosphorus starvation by producing enzymes and other chemical agents that can dissolve both mineral and organic phosphorus compounds to liberate soluble orthophosphate, the form of P taken up by plant roots. Currently, they are studying the phosphate starvation inducible

(PSI) genes that regulate the production of these agents.

Using the techniques of molecular biology, it may be possible to

"supercharge" these genes so that they provide sufficient bioconversion capacity to grow an entire crop. Since a voracious phosphorus feeder such as potato might use 20 pounds of P per acre to grow, the ton of unavailable P in an acre furrow slice could provide fertilizer for many years. A periodic intervals, a new supply of insoluble P could be added to the soil.

Dr. A.H. Goldstein

Department of Plant Sciences

A New Gene Type Aids

Bio Engineers

An important goal of plant scientists is to improve crop yields using genetic engineering techniques. The most promising contemporary approach is to introduce novel genes into the chromosomes of plant cells and to regenerate these cells into plants which produce a crop with improved yield or which produces a new, valuable product, such as a natural insecticide or a higher quality protein in the seeds or forage. To achieve these aims, the structure, function and expression of genes found in plant cells must be fully understood.

Plant cells contain three important corn

partments (organelles) which carry functional genes in DNA molecules.

These organelles -the nucleus, chloroplast and mitochondrion -interact to coordinate the expression of their genes which results in synthesis of the proteins and nucleic acids which carry out the metabolic functions of a plant cell.

Our laboratory is engaged in research to understand the structure and function of genes in the chloroplast -the organelle responsible for photosynthesis. In partcular, we have studied several genes whose products are involved in protein syrithesis inside the chloroplast. Ultiflately, our results will be used to develop strategies for introducing, into chloroplasts, genes which might enhance crop yields.

Our research, in collaboration with other UA scientists, rias focused on one highly unusual chloroplast gene. Named rps12, it is arranged on the chloroplast chromosome in such a way as to necessitate a new mechanism of expression which is unprecedented in genes of other organisms studied to date.

The gene consists of two regions separated by many thousands of base pairs.

There are two copies of one end of the gene and only one copy of the other end. This arrangement of gene parts requires that at least two different RNA molecules, a copy of each different part of the gene, must be spliced together -a process called trans- splicing- in order to assemble a cornplete messenger

RNA which can be translated into the rps12 protein.

These surprising results have broad implications for evolutionary biology.

Indeed, a widely -held view is that genes have evolved fron different DNA segments (called exons) which are shuffled to produce more çornplex genes. A typical gene will have two or more exons joined in a continuous DNA sequence which is subsequently expressed as a single RNA molecule. Our finding of a highly evolved, byt fragmented, rps12 gene suggests that mechanisms which favor the existence of genes which consist of separate coding portions (exons) may have also evolved. Fragmented genes like rps12 which require trans splicing for expression of the encoded proteins will surer, be found in other organisms in the fut ure.

Dr. Don P. Bourque

Department of Nytrition and

Food Science


Developing Natural Pesticides

Plant chemists and microbiologists at the Bioresources Research Facility are using a variety of bacteria, fungi and yeasts to convert naturally occurring chemicals into new pesticides. Since these products result from biological processes, they should be more readily degraded in the environment than many man -made agricultural agents.

There are compelling scientific and practical reasons for doing this work.

Considerable crop losses of agriculture to pests, high prices paid for pest control, evolution of pesticide- resistance in insects, and negative environmental effects of commonly used synthetic pesticides have all resulted in an urgent interest in chemical ecology. This has resulted in a growing demand for new biological controls. Additionally, a need exists for genetic reserves of pest- resistance, which can contribute to breeding programs for new or improved crops.

Negative plant- insect interactions, as well as other types of plant- animal interactions, have been observed and utilized for human benefit for centuries.

Historically, naturally occurring plant chemicals have been an imporant resource for the development of pesticides, both for their direct use as well as prototypes from which more useful pest control chemicals could be developed by chemical synthetic methods. The isolation and identification of natural plant products for potential use in agriculture has increased sharply during the past ten years.

In the past decade, modifications of different types of natural plant products have been the basis for the design of new biocides. Our research is exploring an undeveloped area for producing novel biological controls. The positive results of the work are just beginning to be realized. We have recently filed a patent disclosure on the use of our bioreactor system to produce a novel diterpene that could serve as the starting material for a new generation of biocides. We believe that this study is an enormously practical and worthwhile endeavor.

Dr. Joseph J. Hoffmann

Office of Arid Lands Studies

Caducous Bract Cotton

All commercial cutlivars have persistei it bracts. These bracts dry before the bolls open, they adhere to the seed cotton, are picked with the seed cotton, and upon ginning, become the hard -toremove trash that is mixed with the lint.

Bract particles are a major component of cotton dust which is the cause of the illness called byssinosis or "brown lungs" that afflicts some one -half million textile workers in the U.S.

Our efforts to breed and develop a bractless cotton was started some 20 years ago. Although we did not find a bractless cotton, we have bred and developed a caducous bract cotton bracts which fall before the bolls open.

After examining all the species in the genus Gossypium, we learned that the caducous bract trait was found in two cultivars was started with commercial varieties used as the recurrent parents.

wild lintless diploid species -G. armourianum and G. harknessii, relatives of the commercial tetraploid cotton. We use G. armourianum, a species endemic to islands in the Gulf of California in

Mexico. G. armourianum has only 13 pairs or 26 chromosomes. G. hirsutum the commercial cultivar has 26 pairs o.

52 chromosomes. When transferring genes or chromosomes from a diploid to a tetraploid, the task comes more complicated because of the difference in chromosome numbers. After making a hybrid between G. hirsutum and G. armourianum, the sterile triploid of 39 chromosomes was treated with col chicine to double the chromosome number to 39 pairs or 78 chromosomes.

We made a new species, an hexaploid not found in nature. Fertility was a problem at first, but once fertility was improved, and the caducous bract trait could be identified, a back -crossing program to transfer the trait to commercial

After several cycles of back -cross breeding and selection, our goal of a tetraploid caducous bract cotton with


In tissue culture labs new plants are grown from a few cells of another.

52 chromosomes was achieved. The newly developed 52 chromosome caducous bract cotton appears as normal looking commercial cultivars. The fiber properties (fiber length, strength and fineness) of the newly developed caducous bract cotton are variable, but there are sufficient variabilities in fiber properties that selections can be made in an acceptable range of our commercial cultivars.

Preliminary tests on the genetics of the caducous bract trait show that it is a recessive trait governed by two pairs of genes, and is simply inherited with some modifying genes which causes the variation in the penetrance and expressivity. The variability in penetrance and expressivity remains a puzzle. Our observations seem to indicate that it is stress related. Once the penetrance and expressivity of the caducous bract trait is stabilized, a release will be made so commercial breeders can transfer the trait into their own varieties.

Dr. H. Muramoto

R. Sherman

C. Ledbetter

Department of Plant Sciences

Remote Sensing:

A High Tech Tool

Remcte sensing involves the measurement of soil, water and plant properties of the earth's surface without direct physical contact. Remote sensing techniques exploit the complex manner in which incident solar radiation interacts with the earth's surface. Red and blue spectral light are strongly absorbed by

L. G. KETCHUM the chlorophyll and caretonoid pigments of actively photosynthesizing vegetation. By contrast near -infrared radiant flux is strongly scattered by healthy leaf tissue while the mid infrared is absorbed by leaf moisture.

The characteristic spectral radiance signals of vegetation are used to infer biophysical properties related to pigment absorption, green leaf density and canopy water content. Soil surfaces also reflect and absorb incident solar energy but in accordance with their mineralogi cal, moisture, organic and roughness properties. The synoptic capability of aircraft and spaceborne multispectral sensors provides us with an opportunity to study the earth as a system and to monitor global processes such as terrestrial productivity and environmental stress on regional and localized scales.

At the Maricopa Agricultural Center, an interdisciplinary group of scientists from the UA, USDA and U.S. Geological

Survey are combining remotely sensed data from aircraft and space with onsite meteorological sensors to evaluate evapotranspiration at regional and field levels. Spaceborne sensors provide, instantaneously, thousands of surface temperature measurements over entire agricultural areas and watersheds. Canopy temperatures are used to detect water and nutrient stress in plants before they become visible to the eye.

Timely spectral information from airborne radiometers, thermometers and multispectral video is also being used to study the temporal dynamics and spatial behavior of the earth's surface in rangelands, desert communities, and in cotton, alfalfa and grape fields. This is an integral part of a current environmental impact monitoring program at the Palo

Verde Nuclear Generating Station, where we are trying to assess long and short term effects of salt deposition on surrounding agricultural fields and desert.

Dr. Alfredo R. Huete

Department of Soil and Water Science


Studying Microbe and

Plant Interaction

Like humans, plants are host to a wide variety of microbial inhabitants. Most are harmless, and some even contribute to health and vigor, but when the balance shifts in favor of pathogens disease occurs. If we could somehow make sure that there are always more "good ''mi crobes than "bad" ones, we could go a long way toward controlling disease.

In areas like Arizona where soil -borne organisms cause most plant diseases, keeping the balance right in the soil and in the rhizosphere (the area around plant roots) is especially important. Unfortunately, the soil is a very complex mixture of everything from dead animals to leftover herbicides, and such systems are extremely difficult to control sufficiently to answer questions about how microbes and plants interact. To get around this problem, we are using a new plant cell culture method in conjunction with using plants grown in soil to try to identify specific plant and bacterial genes that enable microbes to successfully make plants their home.

The tip of each plant root has a special region that produces a constant supply of new cells called root cap cells. These cells, which slough off to form a protective sheath as the root moves through the soil, for many years were thought to be dead or dying even before they left the root. In fact, the isolated, detached cells can survive for a week or more in the soil. Our recent discovery that the isolated cells can even be induced to divide and grow in test tubes led us to investigate the possibility that root cap cells play a more important role in the biology of the root than has been recognized.

Our research revealed that root cap cells are very selective about the bacteria they will associate with. For example, root cap cells from pea, a plant that is susceptible to a disease called crown gall, can bind large numbers of

Agrobacterium tumefaciens, the soil borne pathogen that causes crown gall.

In contrast, cells from resistant plants like oats do not bind the bacteria. Fur-

Binding of A.tumefaciens to an isolated root cap cell.

thermore, A. tumefaciens mutants which do not bind to isolated root cap cells from a particular plant do not infect the plant or colonize its rhizosphere.

Work is now in progress to genetically characterize the properties of bacteria and plant surfaces that are involved in the selective interactions we have observed. Identification of the plant and bacterial genes that allow them to recognize one another could bring us closer to developing methods for keeping the microbial balance shifted in favor of plant health.

Dr. Martha C. Hawes

Department of Plant Pathology

A Little Plant With A

Big Future

Progress by plant molecular biologists has been hindered due to the complexity of the total genetic material

(genome) found in most of our common crop plants. Not only do crop plants contain lots of highly repetitive DNA of unknown function, but they often contain extra copies of entire chromosomes. This genetic complexity of our crop plants increases considerably the difficultury of utilizing the techniques of biotechnology to modify plant genes.

To overcome problems associated with the complexities of the plant genome, renewed interest has occurred in a small, harmless weed of the mustard family named Arabidopsis. Arabidopsis has been used for decades by botanists for classical genetic studies because its small size and rapid life cycle are ideal for research.

The reason there has been recent interest in Arabidopsis is that, unlike most of our crop plants, Arabidopsis contains a very small amount of DNA for a higher plant. For example, its DNA content is only about I percent that of wheat and unlike wheat, it contains very little repetitive DNA. Thus, it is much easier to study and manipulate genes in Ara bidopsis than it is in most crop plants.

Since many genes in Arabidopsis are similar to those of other plants, once a gene is isolated from Arabidopsis it may be used to find one like it in some of our more important crop plants.

In the Department of Plant Sciences, we are using Arabidopsis to isolate a mutant gene which has been shown to confer increased salt tolerance in bacteria. We hypothesize that a similar gene mutation in Arabidopsis will protect it from the harmful effects of salt in its irrigation water. We choose to look for the mutant gene in Arabidopsis because the small size and simplicity of its genome increases our chances of finding the mutant gene among the thousands of other genes present.

Isolation and characterization of this mutant gene in Arabidopsis will enable us to determine its usefulness for increasing salt tolerance in economically important crops such as the closely related vegetables, cauliflower and broccoli.

Dr. Frederic R. Lehle

Department of Plant Sciences




Casa del Agua Update

December 1986 marked the completion of the first year of monitoring the various water conservation systems installed at Casa del Agua, a research and demonstration water conservation house. This typical 3- bedroom, single family residence has been occupied by a family of three who has been monitoring water use in the home. The house was relandscaped and retrofitted with low water -use plumbing fixtures, storage for captured rainwater and treated graywater and graywater treatment system.

Preliminary data indicates that the amount of municipal water used at Casa del Agua for the period December 1,

1985, through November 30, 1986, was

58,508 gallons compared to the average

Tucson use of a single -family household of 123,422 gallons. Thus the various systems installed at Casa del Agua decreased overall municipal water needs by some 53 percent.

Figure 1.

20000 -

City Water Used At

Casa del Agua vs. Tucson Average



15000 o

10000 -

5000 o


`' w


Q z

1985 -1986

< cñ O Z

Figure 2.

Monthly Water Input For

Flushing Toilets

At Casa del Agua n, cd C On tl. Ú>

^~Q L'A O °

1985 -1986

The systems installed at Casa del Agua have significantly reduced the peak in demand for city water that typically takes place during the summer. The average Tucson household input of groundwater more than doubles from

6,732 gallons during the month of

February to 15,708 gallons during July

(Figure 1). Peak water use at Casa del

Agua occurred during the month of June when nearly 9,000 gallons of water were used; however, the total amount of city water used was less than 7,000 gallons.

The use of conventional toilets requires

31 gallons per person per day. The one gallon toilets installed at Casa del Agua reduced the amount of water needed to flush toilets to less than 8 gallons per person per day (Figure 2). The use of these toilets reduced water use at Casa by more than 20 percent. During the summer one of the major uses of water at Casa del Agua was for the evaporative cooler which used approximately 100 gallons per day.

Dr. Martin Karpiscak

Office of Arid Lands Studies


Landscaping Saves Dollars

Appropriate landscaping may save

Arizonans nearly one -half of their annual cooling costs in low elevation desert areas.

A computer program designed to simulate the effects of trees and shrubs on the energy required to cool and heat homes has been developed within the Division of Landscape Resources.

Costs for two identical 1,540 square foot homes were compared for a similar, but completely unshaded house. The energy- conserving planting design has high branching, wide spreading trees that shade the roof and walls from the summer sun but allow sunshine on the south wall in winter. The late afternoon sun is blocked by low -branching evergreens, and deciduous shrubs shade the north and east walls from early morning summer sun.

In the energy- consuming design, trees grow only on the south side. The trees are so dense that they block the winter sun, but are not tall enough to shade the house during the summer.

The energy- conserving design in

Tucson reduces annual cooling costs

44 percent ($193) and increased heating costs 10 percent ($10) for a net annual savings of 33 percent or $183. On the other hand, shade from trees in the energy- consuming planting design increased net annual energy costs by only

$17. Because heating is needed primarily at night and because heating usually represents one fourth of total space heating and cooling costs, plantings that block winter sun in Tucson don't cause the large increases noted in other test cities in the U.S. Effects of vegetation on building energy performance were also tested in Salt Lake

City, Miami and Madison.

The peak cooling load for the house in the energy- conserving design was

35 percent (10,000 Btu) less than for the unshaded house. Hence, homeowners with mature plantings around their home could replace old coolers with

Energy -Conserving Design

Energy- Consuming Design

smaller and more economical systems that will maintain comfort levels because peak cooling loads are reduced.

Additionally, wider use of tree shade in

Arizona could reduce the need for electric utilities to invest capital in costly new generation facilities required to meet peak load demands.

Research by other scientists suggests that vegetation in cities can reduce the urban heart island effect by 50 percent.

For example, in Phoenix nighttime minimum temperatures are now approximately 10 degrees F warmer than recorded 30 years ago due largely to the replacement of irrigated fields with buildings and streets. Increased plantings in Phoenix may result in temperature reductions that could substantially reduce commercial and residential building energy consumption and beautify the city.

Drought -tolerant trees and groundcovers, primarily irrigated with water harvested and recycled on the site, are the recommended plant ings.The Department of Energy grant will fund field tests to measure the effects of different landscape treatments around residences on both energy and water use.

Greg McPherson

School of Renewable Natural


W- Index.

Measuring Water Savings

The "W- Index" is a numerical index of residential water efficiency. It provides a systematic method for listing and evaluating the water -conserving features in a residential unit, in three parts- indoor water -saving features, outdoor water saving features, and water augmentation and recycling systems.

The index concept can be used by architects, builders, appraisers, homeowners, water suppliers, or water management agencies as a basis for comparative evaluation of water -saving capability in any particular dwelling unit.

Listed on the W- Index" worksheet are the principal water using /water saving features along with suggested numerical values for each increment of water conservation (in units of thousalnds of gallons per year saved). The actual features existing in any given residence can be checked off, and the incremental values totalled to arrive at the "W-

Index" value for that residence. The worksheet is designed to apply to water supply and water -use conditions in the

City of Tucson water service area.

The indoor features considered in the calculation are as follows:

- toilets

- showers

- faucets

- dishwashers

- washing machines.


Good landscaping contributes to visual quality.

The outdoor features include the following:

- swimming pools

- evaporative coolers

- landscaping

type of landscape plantings method of irrigation.

The water augmentation and recycling features included for indexing are as follows:

- municipal water (basic supply)

- use of bottled water

- graywater recycling

- rainwater harvesting (rooftops and hard surfaces)

- runoff harvesting by landscape sloping and contouring.

Initial index values for conservation are assigned to the appropriate items above, and the initial values are adjusted for interactions (for example, a water -saving showerhead would cause less graywater to be produced, thus diminishing the conservation potential of a graywater recycling system). Further adjustments are made for demographic variables, resident characteristics, and housing type, to arrive at a final

"W- Index" value for the household.

Dr. K. James DeCook

Office of Arid Lands Studies

Cleaning Wastewater With


A water hyacinth wastewater treatment plant is proposed for construction at the

Roger Road Wastewater Treatment Facility by the Pima County Wastewater

Management Department during 1987.

The potential use of water hyacinths was discussed in a report prepared for

Pima County by the Office of Arid

Lands Studies.

Since the latter part of the 19th century water hyacinths have flourished in the stagnant freshwaters of the southern coastal states where they are considered a nuisance. Dense concentrations of these plants block waterways, creating mosquito breeding grounds, and destroying native habitat. For the past

15 years, however, water hyacinths have been used to treat sewage.

The pilot plant is designed to accept approximately 50,000 gallons of primary feedwater per day and treat this wastewater to secondary standards, and with site specific management, advanced wastewater standards. The research results provided by this facility will provide the information necessary to permit a decision as to the feasibility of building and operating a full- scale system of 1 to 10 MGD in Tucson.

This pilot plant facility will enable researchers to explore the following issues: cold stress and possible winter dieback; the use of other aquatic species such as duckweed; evapotranspiration rates which might approach three times that of open water in summer; possible nuisances such as mosquitoes and odors; the effects of toxic pollutants on the functioning of the water hyacinth system, and the ability of water hyacinths to remove selected toxins such as copper or phenols.

A full -scale water hyacinth treatment system could significantly reduce capital costs (by 30 to 50 percent) as well'as operations and maintenance expenditures (by 50 to 85 percent). In addition, water hyacinth systems may produce useful by- products such as soil conditioners, animal feeds and biogas.

Dr. Kennith Foster

Office of Arid Lands Studies

Improving Visual Quality

Most people are aware of the rapid growth of Arizona's cities. Growth usually means change. Many cities and towns have planning and zoning ordinances which direct growth and change by controlling land uses and transportation, but seldom the visual or aesthetic quality. How can cities assure visual quality? After acknowledging that visual quality is important, they can take action by developing a Visual Quality Plan.

Psychologists and physiologists tell us that as much as 75 percent of perception is visual. Visual perception of our surroundings affects our mental health and well- being. We need to examine the visual quality of our cities, and develop plans to guide the quality of the visual environment during growth and change.

For three years, students and faculty in the Division of Landscape Resources, have been studying the visual quality of

Arizona's smaller cities. The study team has inventoried several Arizona cities to identify visual quality issues. These issues are: 1) unrelated land uses, 2) lack of relationship between the city and the surrounding natural environment,

3) use of inappropriate building and landscaping materials, 4) variety of architectural styles, 5) absence of control over certain systems (signage, utility poles and lines, street furniture, etc.)

6) lack of pedestrian amenities, and

7) townscape maintenance.

To assist citizen groups and public officials, a planning process was developed which offers solutions to identified issues leading to a Visual Quality Plan.

This plan can be used to guide improvement in townscape quality. As Arizona cities continue to grow, citizens need to be aware of the potential of this change for improving or degrading visual quality. A Visual Quality Plan, representing the goals and objectives of residents and officials, offers guidance in upgrading the existing environment and promoting visual quality of future growth.

William H. Havens

School of Renewable Natural




Cultivating agave at the Marana

Agricultural Center near Tucson.


"The greatest service which can be

rendered any coun-

try is to add a useful plant to its culture, especially a bread grain."

-Thomas Jefferson


Thomas, Jefferson was a man of vision.

Today's reality is of large capital investment changing the face of agriculture and indeed the whole planet. Mass production in agriculture has brought the dependance on "The Big Three" -

Wheat, Corn, and Rice. The three grains account for 40 percent of the world's food. Of the more than 200,000 higher plant species a mere 50 species produce 99 percent of our food! Research at the UA College of Agriculture is invblved in broadening our crop base, especially in arid climates.

One recently developed, though yet little -known, plant with immense potential is a variety of salt grass of the genus Distichlis and is trademarked

WildWheat. The plant belongs to the

Poaceae, like wheat and barley. Bread made from WildWheat flour is not significantly different from whole wheat bread with respect to flavor, texture, appearance or overall preference. Interestingly, a mixture of WildWheat and whole wheat was significantly preferred over either alone.

The WildWheat grain has a nut -like flavor and some of its nutritional characteristics are superior to those of wheat: higher fiber, balanced amino acids, "low" salt content, very low in mineral- trapping phytates, and the grains lack a potentially allergenic

protein -gluten -present in wheat.

The WildWheat plant (patents pending) grows well in hot arid climates, but its most striking feature is its ability to show increased growth in heavy, saline soils. It will grow well if irrigated with full- strength sea water under hot, arid conditions. Related varieties of

Distichlis are being used successfully as forages.


A variety of Distichlis grown in tissue culture has become an object of biochemical and molecular biology studies into the mechanism of salt -tolerance.

These studies are designed to trace and explain the series of events that link the perception of stress with the induction of genes, and the expression of altered biochemical pathways which enable this plant to thrive under conditions that inevitably eradicate most of the presently available crops.

Most significantly these studies may yield critical information allowing us to understand exactly which and how many genes are involved in salt tolerance, how they operate, and what their effect will be after gene transfer into a crop species that is not salt tolerant.

Dr. Hans J. Bohnert

Department of Biochemistry

Dr. Nicholas Yensen


Frequent travelers between Tucson and

Phoenix are noticing some new scenery. Row upon row of symmetrically spaced rosettes dot the field adjacent to the interstate at the Marana Agricultural

Center. These are agaves under cultivation -and apart from a field plot established in Phoenix a number of years ago by Dr. Howard Gentry -the first attempt at agave cultivation in

Arizona using modern agricultural technology.

Agave is a multi -use crop in many locations worldwide. Grown for cordage fiber in Africa, medicinal steroids in

India, for quality paper production in

Brazil; and of course for tequila production in Mexico, these desert succulents hold promise for Arizona agriculture.

A second agave field has occupied several acres of City of Tucson former farm land in Avra Valley for seven years. The

Avra Valley agaves haven't received a drop of irrigation water in those seven years, and are thriving. One agave species at Marana, with a few supplemental irrigations, produced specimens which weighed nearly 800 pounds in the same time period. Data on growth rate, steroid and fiber production are being gathered on these plants.

While the Marana field is conspicuous, one has to be observant to notice the dagger -tipped agave leaves above the abundant stand of seeded range grasses at Avra Valley. This location is designed to yield a man -made simulation of the agave -grass climax vegetation thought to have existed in Arizona in the past. A similar agave -range grass "symbiosis"

has been established on several acres in a remote corner of the Page Range Agricultural Center. These fields are part of a long term study on the cooperative coexistance of plants which may help serve to invigorate our ranges and to stabilize fragile desert soils.

Stress tolerant, agaves can be managed as a low input perennial under cultivation. Our present studies are also designed to determine whether agave can be grown in areas where conventional crops such as cotton are no longer profitable.

Dr. Robert G. McDaniel

Department of Plant Sciences


Gumweed is another promising new

"industrial" crop for arid areas. Gum weed consists primarily of diterpenoid resin acids similar to those in pine wood rosin. Rosin is used in the manufacture of inks, paper sizing, adhesives, and tackifiers.

Production of resin acids from U.S. forests has declined steadily in recent years. The labor costs of obtaining gum rosin from living trees have become prohibitive while the supply of old pine stumps for extracting wood rosin has nearly become exhausted. In less than

30 years the U.S. has gone from the world leader in rosin production (more than one billion pounds annually) to becoming the world's leading importer of gum and wood rosins.

The domestication of gumweed seeks to recapture a portion of the resin market lost to overseas producers, while providing a new crop for Arizona growers. Gumweed offers potential high returns per unit input of water, since their industrial products have a much higher value than food or fiber.

The development of such new industrial crops will require the coordination and cooperation of both the manufacturing and agricultural sectors. In the cases of both gumweed and guayule, industrial investment in a local extraction facility will be required to provide a market for the grower.

Gumweed is one promising "industrial crop."


Agronomic studies have shown that gumweed grown at the Office of Arid

Lands Studies' Bioresources Facility yields up to 1,050 pounds of resin per acre with 26 inches of applied water.

Resin yields will have to be improved somewhat for gumweed resin to become competitive with imported wood rosin.

Recent studies have focused on the variation in resin yield and other important agronomic characters. Much of this variation has been shown to have a genetic basis. Collections with the best potential for resin yield, biomass production, and drought tolerance have been identified and crossbred. Their progeny, along with new collections from the wild, are being grown and evaluated at the Bioresources Research Facility.

Dr. Steven R McLaughlin

Office of Arid Lands Studies

Alternative Vegetables

The New Vegetable Demonstration

Garden at the Yuma Valley Agricultural

Center provides an opportunity for growers, extension agents, farm personnel and researchers to see a few varieties of vegetables currently not

(widely) grown in Arizona. The vegetables were selected for their uniqueness, adaptability, horticultural potential and availability. New Vegetable Demonstration Gardens will also be established at the Yuma -Mesa and Maricopa Agricultural Centers this spring.

The fall garden consists of 22 kinds and varieties of vegetables, mostly European and Asian cultivars, currently grown on limited acreage. Due to increasing grower interest and demand for specialty crops several varieties of

Chinese cabbage (napa, michili and pak choy), chicory (radicchio and green, non -forcing) and non -heading lettuce varieties were included. In the future, we will try to include representative cultivars of those vegetables that are not only currently popular in salad bars and specialty shops but also new untried vegetables with no current market or some that may have been "traditionally" produced in other areas of the country.

The selections for the spring garden include cowpeas, pepino, naranjilla, kiwano, and yacon and Apios americana. Cowpeas are used as dry beans

(blackeye pea typés) or as a fresh vegetable (crowder or cream types) and have been traditionally a "southern" crop. Cowpeas are a heat and drought tolerant legume with a high protein content; the crop has additional potential as a forage, green manure or intercrop.

Pepino dulce or melon pear is a relatively new crop related to tomatoes and peppers. The fruit is about 6 inches long and 3 inches in diameter with a yellow flesh and a flavor that has been described as a "cross between a honeydew melon and strawberry." Lulo, or naranjillo, is similar to pepino dulce but is a perennial crop.



Tepary beans.

Kiwano is also known as the African horned cucumber; it is currently produced commercially in New Zealand. It is related to and used like our common cucumber but the appearance and flavor are somewhat different.

Yacon is an edible enlarged root in the sunflower family and is similar in appearance to Jerusalem artichoke or jicama. The flesh of the root is very juicy, crunchy and mildly sweet and can be eaten raw or cooked.

Apios americana has recently been evaluated as a potential food crop. It is a viney legume that produces sweet starchy tubers and seeds. Although it prefers waterlogged acidic soils, it is heat tolerant and may be adaptable.

These crops represent only a few of many potential new vegetables for

Arizona. If any of the plants show potential for commercial production in

Arizona and there is sufficient grower interest, more in depth research may be warranted.

Dr. John McGrady

Department of Plant Sciences

Tepary Bean

At the 1912 International Dry Farm

Congress held in Canada, our Arizona native tepary bean received special honor for its flavor and reliability of yield under rain -watered conditions. As irrigation became predominant, interest waned in this hardy, arid- adapted legume. In recent years the need to develop alternative crops using minimal water has stimulated renewed interest in this Sonoran desert legume.

Teparies have a unique appealing flavor.

Their cooking time is longer than that for pinto beans, but a variety of nutritions and savory culinary creations can be prepared with them. While they show some deficiencies in certain nutrients typical of the legume family, the quality and quantity of their protein, mineral and vitamin contents rival those of commercially available beans.

In a well developed country such as the

United States, where reliance on local food production is unnecessary, the nutritional significance of a decline in tepary use has little impact. However, if teparies were to be introduced into lesser developed areas of the world suitable to their culture, their nutritional significance might possibly be measured by the difference between adequate legume procurement or crop failure.

To assess acceptability of teparies in

African and Middle Eastern regions, traditional Nigerian and Saudi Arabian foodstuffs were formulated with teparies substituted for beans commonly used in these regions. Sensory evaluation of these food products by students native to the area of recipe origin indicated the dishes to be moderately to highly acceptable.

These results suggest an opportunity to introduce tepary beans in those areas of unreliable food supply. Although no barrier to use of this species in African/

Middle Eastern food supplies has been found, its incorporation within these cultures must await further nutritional evaluation.

Dr. James W. Berry

Department of Nutrition and

Food Science


Teenage Nutrition

Adolescents characteristically have unique nutritional needs. With the exception of the first year of life, the growth rate during adolescence is greater than at any other time in life.

Physical changes taking place during this growth period include increases in height and weight, deposition and redistribution of fat, increased lean body mass, and enlargement of many organs. Because nutrition is intricately related to these physical changes, requirements for nutrients and energy are greatly increased.

In recent years, the incidence of anorexia and bulimia in adolescents has gained national attention. Other common practices include extremely limited food selection, fad dieting and binge eating.

UA nutrition educators are joining those from five other states in a concerned effort to determine the best method to communicate with teens in regards to nutrition and food concerns. This research is based on communication theory and centers on "receiver oriented" rather than "sender oriented" messages.

Individuals have unique methods of processing information. "Sender oriented" messages do not take into account that a message has information value to a receiver only to the extent that it can be interpreted, understood and applied by that receiver to his /her own time, place and perspectives. This frequently accounts for the "communication gap" which is noted between generations.

Initial research at the UA has focused on determining adolescents' perceived nutrition information needs using a sense -making approach developed by communications researchers. Arizona teens' major concerns appear to be focused on dieting and weight control, fitness and athletic performance, and more general concerns as to the safety of foods. Both girls and boys were consistently trying to "master" or "figure out" nutritional situations, with both sexes greatly preferring to receive help or information from non -personal sources. Girls reported worries or concerns about food, nutrition and eating more frequently than boys.

Results from this and other research may assist experts in developing truly receiver -oriented public communication campaigns to reach nutritionally vulnerable adolescents.

Dr. Ann Tinsley

Department of Nutrition and

Food Science

Diet and Heart Disease

Many Americans are concerned about how their diet, particularly dietary saturated fat and cholesterol, may be related to increased risk for heart disease.

There is a different concern in agriculture that animal food products, such as eggs, red meats and dairy products which play such an important role in a balanced and nutritious diet, are often considered by the consumer as bad or unhealthy foods.

Numerous dietary recommendations have been given to the public to reduce dietary fat and cholesterol intake as a means of reducing blood cholesterol levels and theoretically heart disease risk. Two problems with such generalized dietary recommendations are that people initiate dietary changes without knowing whether they need to or not, and after they do so there is no process to find out whether blood cholesterol levels are reduced.

UA nutritional scientists are studying two facets of the diet -heart disease relationship by determining the variations between patients in response to dietary changes and how such changes affect the process of plaque formation involved in the development of heart disease. Techniques are now available to not only determine how a diet alters blood cholesterol levels but to also measure the effects of diet on the various blood lipoproteins, which carry cholesterol, and the production of cholesterol in the body.

Studies of volunteers on low and high cholesterol diets show that most individuals can readily handle an increase in dietary cholesterol by reducing the amount of cholesterol the body produces. The fact that most people are relatively insensitive to dietary cholesterol raises serious questions about generalized dietary recommendations if a large number of people would not gain a cholesterol lowering benefit.

Not only is it important to understand how diet affects blood cholesterol levels but to determine whether changes in the diet alter the actual process of plaque formation in the blood vessels of the heart. Using a cell model system, UA nutritional scientists are investigating the relationship between dietary fat and cholesterol with the accumulation of cholesterol within a cell type considered to play a role in plaque build up. By determining whether diet alters this interaction on an individual patient basis it is hoped that it may be possible to design the most effective diet based on the need of the patient.

Dr. Donald J. McNamara

Department of Nutrition and

Food Science




Geographic Analysis of

Retired Farmland

Thousands of acres of groundwater irrigated agricultural land have been idled in the Southwest because of the high cost and decreasing availability of groundwater, low commodity prices, high interest and energy costs. One ecological consequence of retired farmland is the likelihood of desertification.

The loss of topsoil and presence of undesirable plant species can turn formerly useful and productive lands into wasteland.

Cochise County has experienced a significant decrease in active agricultural land. Hence, it served as a case study area for a demonstration in computer assisted mapping from aerial photography to quantify impacted farmland. The goal was to map fields removed from active agriculture and the period of time during which retirement occurred. The mapping activity enabled more detailed sampling of revegetation according to time out of production and to identify possible patterns of retirement related to location and time of retirement.

Locally available photographs taken by

NASA and ASCS were used to map the fields. This imagery varied in coverage, format and scale. For the years 1972 through 1984, agricultural fields were identified and classified as active, inactive or fallow when appropriate.

Agricultural status draft maps for the years under photography were converted to digital form through the use of an Earth Resources Data Analysis System (ERDAS) geographic information mapping system at the Office of Arid

Lands Studies. In addition, overlay maps of a section grid and land ownership were entered on ERDAS and registered to the agricultural status maps. The resulting data on active and inactive land then were compared with existing county agricultural service data and found to be acceptable.


Active (1984)

1982 -1984

1976 -1982

Table 1. Farmland in Cochise County by period

Fallow (1984)

Out of production:

1972 -1976

1958 -1972 pre -1958

Sporadically farmed

Area (ac)








124421 of Total Farmland









From analysis of the map data, the greatest net decrease (11.8 percent of total farmland) in productive farmland within Cochise County took place between 1976 and 1982. Because of potential misclassification of retired farmland as inactive or fallow, however, more actual retirement may have taken place during this latter period. Even after adjusting for the different period lengths, the period 1958 -1972 showed very modest decline (2.0 percent of total farmland). Table 1 provides specific data on decline for each period.

Digital mapping and analysis facilitated identification of agricultural decline and afford a method of locating areas within the region with potentially severe impact.

Dr. Martin M. Karpiscak

Dr. Michael C. Parton

Dr. Christina B. Kennedy

Office of Arid Lands Studies

Improving Forest Soil With

Gambel Oak

Gambel oak is widely distributed in the southwestern ponderosa pine forests and the higher elevations of pinyon juniper woodlands. This oak grows as a shrub on unfavorable sites with shallow soil and as a tree on favorable sites with deep soils. Gambel oak sprouts readily from the trunk base and grows in small, scattered clumps in association with ponderosa pine. It is poisonous for livestock, but is considered a source of browse and mast for deer and wild turkey. Local residents harvest it for fuel wood.

Despite these various uses, Gambel oak is a low value tree species and forest managers have treated it as a weed. But this attitude may be short -sighted.

Broadleaved trees are recognized for their beneficial influence on the chemical and physical properties of forest soils. Perhaps Gambel oak contributes to the overall nutrition of the ponderosa pine forest.

Twelve years ago studies were begun in the School of Renewable Natural Resources to investigate the influence of

Gambel oak on the forest floor and upper soil layers of the pine forest. These studies which have been conducted on the Coconino National Forest show that many physical and chemical properties of the forest floor and soil are improved when oak is present. The concentrations of nitrogen, phosphorus, sulfur, calcium and potassium in the forest floor and 0 -5 cm layer of mineral soil all increase when oak is associated with pine.

Other studies have been conducted to determine the effect of these additional nutrients. Experiments in the greenhouse have shown that barley plants grow better on soil from stands with oak. Nitrogen, phosphorus and sulfur in the oak soils are all more available to barley. This greenhouse experiment is now being repeated with ponderosa pine seedlings as the test plant to see if the pine seedlings also benefit from the additional nutrients.

The real test of the importance of these findings is to determine if pine trees growing in association with oak in the forest are able to benefit from the improved soil fertility with increased radial growth. This question is currently being pursued.

Dr. James O. Klemmedson

School of Renewable Natural Resources



Managing Lehmann

Lovegrass Rangeland

Lehmann lovegrass is a drought tolerant, warm season, perennial bunchgrass native to South Africa. Since its introduction into the Southwest 50 years ago, the grass has been seeded extensively for erosion control and forage production. It now covers more than 200,000 acres of Arizona rangeland.

Land managers have mixed emotions regarding the invading grass, but few data exist to guide grazing management. The purpose of this study was to provide guidelines for ranchers to incorporate Lehmann lovegrass into traditional and more intensive time controlled grazing management, and for land -preserve managers concerned with interactions among Lehmann lovegrass and native grass species.

In 1983, UA faculty collaborating with the U.S. Forest Service and rancher Bill

McGibbon began a series of cattle grazing trials on the Santa Rita Experimental

Range near Tucson. Pastures were grazed seasonally and yearlong at four stocking rates ranging from 20 to 90 animal units per section. Individual

Lehmann lovegrass tillers were marked in each pasture and checked weekly for grazing. Tiller lengths were measured to estimate defoliation intensity, frequency and timing and rate of growth. Cattle grazing behavior was also monitored.

Contrary to previously published information, Lehmann lovegrass was grazed by cattle in every season, with use increasing during the rain -induced growing season. Cattle grazing patterns created uneven utilization, maintaining patchy areas of heavy use that persisted throughout the study. Grazed patches, once developed, were maintained through close, habitual cropping. Over

75 percent of the grazing events occurred in previously grazed patches, regardless of stocking rate. Cattle continued to re- visit these patches even when tillers were too short to be grazed.

Of the tillers grazed more than once during the growing season, nearly 90 percent occurred in grazed patches.

On Lehmann lovegrass pastures in this study, stocking rates were a minor influence on cattle grazing patterns until extremely heavy levels were reached; seven times recommended numbers.

Once grazed patches developed, cattle foraged in them almost exclusively, ignoring surrounding plants.

Two management alternatives are being considered to disrupt patch grazing and better distribute animals away from favored areas; burning and increased stock densities. Both methods will reduce residual grass stems which restrict animal access to the more palatable new growth.

By changing cattle grazing behavior, we hope to improve grazing efficiency and livestock production on Lehmann lovegrass rangelands while enhancing stands of the remaining native grasses.

Dr. George Ruyle

School of Renewable Natural Resources

Forest Fire Information

The fire policies of federal land management agencies have recently been revised. Instead of requiring that all fires be extinguished immediately, the revised policies allow naturally caused fires that meet certain specified conditions to continue to burn. The new policies also allow the use of deliberately ignited fires, when such use is seen as beneficial to forest growth and management.

A chief concern among forest managers responsible for implementing these policies is public reaction. While wanting to preserve Smokey the Bear's effectiveness in preventing humans from causing unwanted wildfires, forest managers also recognize the need to counter beliefs that all fires are environmentally destructive and to build support for the manager's use of fire to achieve beneficial objectives.

The purpose of this research is to improve the capabilities of forest managers to effectively communicate new fire management objectives and plans. It does this by recommending how forest managers might target fire information programs for best results.

The process involves identifying both intended audience and content -what to say to whom.

To accomplish our task, we drew upon results obtained in three opinion surveys. Two of the surveys were of adults in metropolitan Tucson and the third a national sample of forest users.

It was found that there is a high level of public support for manager- initiated fire management practices. This, coupled with the public's ability to differentiate between situations that result in beneficial effects and those that result in harmful effects, suggests that the audiences to be targeted with fire program information are sophisticated in their fire belief characteristics.

Since public acceptance of allowing fires to burn increases as more information about the fire is given and as control is specified, fire information programs should clearly describe situations where fire needs to be suppressed and situations where fire can be used to achieve beneficial management objectives.

The content of fire information programs needs to be directed toward a broad, cross -section of adults, addressing directly those factors, such as fire size, intensity and impact upon animals, that can cause.emotional concern when individuals visualize an undefined forest fire.

Dr. Edwin H. Carpenter

Department of Agricultural Economics

Dr. Hanna J. Cortner

School of Renewable Natural Resource'

Jonathan G. Taylor

Department of Geography and Recreation

University of Wyoming


Learning More About Desert

Bighorn Sheep

My graduate students and I studied desert bighorn sheep and their relationships with the habitat in the

Little Harquahala and Harquahala

Mountains in western Arizona from

1980 -1986. The study was funded by the

U.S. Bureau of Reclamation and the U.S.

Fish and Wildlife Service as part of a mitigation package for lost habitat from the construction of the Central Arizona

Project. The CAP is designed to deliver

Colorado River water to Phoenix and


In order to study the habitat relationships of these desert adapted ungulates, radio -collars were placed on 34 sheep.

All were systematically located at least weekly from the ground and aircraft.

Locations of sheep were plotted on

G. WEBSTER maps and group size, aspect, slope, topographic position, elevation, vegetative association, behavior, sex and age class were recorded. Different habitats were determined from ground reconnaissance and aerial photographs.

More than 5,000 locations of sheep were made during the study from which home ranges and use of habitats were determined. Sheep were sexually segregated except during rut and they selected specific habitats influenced by season, sex and year.

Most of the remaining indigenous populations of desert bighorn sheep in the

Southwest are small (100). The interactions of desert bighorn sheep to their habitats are complex and it is vital to understand the relationships in small isolated populations such as the Harquahala Complex. Small populations form the backbone for surrounding populations. It is important that studies of desert bighorn sheep continue so data are provided which allow a better understanding of how desert bighorn sheep interact with their environment.

Dr. Paul R. Krausman

School of Renewable Natural Resources

Tucson's Bighorn Sheep: How Important?

A herd of 70 to 100 bighorn sheep inhabits the Pusch Ridge Wilderness Area of the Coronado National Forest near

Tucson. Urban development within a mile of the herds' prime habitat and increasing recreational use of the area could have negative impacts on the herd. Actions to mitigate these impacts may have to be taken to insure the continued existence of the herd. It seemed logical, then, to ask how important is this herd of bighorn sheep to the people of Tucson?

importance to those households that did not respond, the median dollar value of the herd per household was estimated to be $9.20 per year. Stated in other terms, these sheep are "worth" at least $2.2 million, annually, to


The amount people were willing to pay to preserve the herd increased with their household income, but at a lower percentage rate. This result indicates that the herd is not considered a "luxury" by Tucsonans. There is a willingness to pay for its preservation across all income groups in the community.

We did this with a mail survey of Tucson households in 1985. Survey participants were asked 1) whether they would favor a tax to preserve the herd, 2) how much they thought a management agency should spend, generally, to preserve the herd. and 3) what they would be willing to pay for an annual membership in a foundation which would preserve the herd.

Questionnaires were returned by 550 households, a response rate of 59 percent. A local tax to preserve the herd was favored by 61 percent of the respondents. Overall, 73 percent of the respondents to the survey thought a managing agency should go to at least

"moderate expense" to preserve the herd. Assuming that the herd is of no

Our estimate of the dollar value of the herd is reasonable when compared to values that have been estimated for other species of wildlife such as whooping cranes in Texas and bald eagles in Wisconsin. All of the estimates, indicate that people are concerned about and support the preservation of wildlife species and of particular populations of wildlife, such as the Pusch

Ridge herd of desert bighorns.

Dr. David A.King

Dr. William W. Shaw

School of Renewable Natural Resources


Managing Arizona's Riparian Lands

Landscapes that are endowed with the full range of values challenge managers to balance competing demands of special interest groups. Within desert areas, riparian landscapes (those along natural waterways) most frequently encompass this full range of values and have been subjected to competing demands and conflicting uses for centuries.

In 1986 a mail survey was conducted of the perceptions, attitudes and opinions of the general public and special interest groups towards the riparian landscape and adjacent lands associated with the upper San Pedro River in Cochise

County. Special interest groups included: realtors, local elected and appointed officials, farmers and ranchers, conservationists, the San

Pedro Water Resources Association, and individuals who have management responsibilities associated with the riparian area. Shortly after the survey was completed, it was announced that approximately 43,000 acres was acquired by the U.S. Bureau of Land

Management and would be managed to meet conservation objectives.

Seventy -five percent of those who received the mail survey responded indicated strong public interest in the topic. A large majority of the respondents agreed on the amenity and environmental values associated with the area and adjacent lands, values such as scenic beauty, wildlife, green vegetation and flowing water. There were, however, significant differences with respect to attitudes about appropriate land uses adjacent to the riparian zones.

Not surprisingly conservationists and resource managers favored conservation oriented land uses while realtors and farmers favored commodity oriented uses. Other respondents tended most towards conservation uses. When responses to farming, grazing and hunting were analyzed, significant differences were found between farmers and ranchers who favored these uses and other subgroups which tended not to.

Important reasons cited in support of these attitudes included: supporting growth and development, maintaining traditional lifestyles and being of benefi to the environment.

There were also important disagreements about the adequacy of planning in the area with all groups except real tors noting that the exisitng level of planning was inadequate to control growth and development.

These and other findings suggest that there are major challenges to guiding the future of this, the fastest growing area in Arizona.

Dr. Ervin H. Zube

School of Renewable Natural Resource


Revegetating Rangeland

By Trampling

When pigs accidently trampled his weed ecology study plots, the well known English population biologist John

Harper was surprised at the subsequent increased emergence of plantain seedlings. He went on to show experimentally that roughening of the soil surface had a beneficial effect on germination and emergence of some plants.

Many studies have shown repeated, excessive soil trampling by animals may have negative effects on the soil, including decreased water entry and increased crusting and compaction.

However, controlled, short -term, low frequency disturbance of the soil by livestock under intensive management may actually encourage establishment of desireable plants. Increased cover of herbaceous plants may then improve soil conditions on the range.

Many rangeland grasses appear to have a critical depth of emergence. Seeds on the soil surface fail to germinate while those buried too deep are unable to emerge after germination. Animal trampling may help bury seeds to the critical depth or roughen the surface and break up the surface crust, thereby lengthening the time of moisture availability to seeds and seedlings on or near the soil surface. Researchers from the

Range Management Division, School of Renewable Natural Resources and from the Department of Soil and Water

Science will be studying these effects over the next three years.

Dr. Bruce A. Roundy

School of Renewable Natural Resources

Dr. David M. Hendricks

Department of Soil and Water Science

Elk Versus Cattle

Federally owned land accounts for approximately 44 percent of the total acreage in Arizona. Much of this public land is administered under a multiple use management policy intended to provide a beneficial mix of land uses for a variety of clientele.

A particular challenge in designing multiple use policy occurs when competing demands for public land involve both commerical and recreational interests.

In these circumstances, the net revenue impacts of commercial activity on public lands must be weighed against the services enjoyed by recreationalists in determining an appropriate mix of land uses.

A case study of this type of management problem was made recently

Apache -Sitgreaves Forest Area in central

Arizona which is managed by the U.S.

Forest Service. Range scientists in the

UA School of Renewable Natural Resources had determined through a series of investigation that grazing land in this area can sustain both elk and cattle herds when their numbers are managed in a way consistent with the range's carrying capacity.

Efficient multiple -use of the area requires an evaluation of the net benefits attributable to modifying elk and cattle herd sizes. On the cattle side, both long run and short -run values of an animal unit year (AUY) of forage used for cattle production on central Arizona mountain ranches were estimated. Net return per

AUY depends on the size of the operating unit. The larger ranches in this area are about 700 AUYS. With yearling steers at $0.58 per pound (near- current

December 1986 values) the long -run marginal value of an AUY is approximately $37. Smaller ranch units do not fare as well. At $0.58 per pound, a 150 -

AUY ranch has a long -run marginal net return of negative $30 per AUY. Should price per pound rise to $0.80, long -run marginal net return per AUY could reach $25.

On the recreation side, a random sample of Arizona Game and Fish elk hunting applications was used to estimate the demand for elk hunting trips.

Demand was estimated separately for each of three hunts in 1979 on this area.

The first was an early -fall rifle hunt with

3,840 applicants but only 400 permit tees. The second hunt was a later -fall rifle hunt with 3,272 applicants and

1,500 permittees. The third hunt was an archery hunt for which there were only

371 first -choice applicants but for which

400 hunters were assigned permits.

Using multiple regression statistical techniques, hunting demand was related to hunting success and elk numbers with the average value of an elk being estimated a $106.

Based on a comparison of recent elk and cattle values, efficient multiple use management would likely require increasing elk numbers. By increasing the size of the elk herd, hunting success rates could be increased and recreationalists would enjoy the benefits of a higher quality hunting experience.

These additional benefits are estimated to more than offset net revenue losses associated with a decrease in cattle numbers.

On equity or fairness grounds, however, the management picture is less clear.

On a per capita basis, losses in net revenue to cattle producers would exceed gains to recreationalists. Thus beneficial multiple use management of this forest land will likely involve increasing elk numbers, tempered by concern for net revenue impacts resulting from declining cattle herd sizes.

The results of this case study illustrate a general methodological framework that can be utilized in a wide variety of multiple use settings to help determine efficient and equitable policy.

Dr. Dennis C. Cory

Dr. William E. Martin

Department of Agricultural Economics


Plant Disease Database

"Does anyone around here remember if this virus on melons has been seen in

Arizona before ?"

"When was that powdery mildew of carrots first seen in Yuma ?"

"What do we know about bacterial diseases of tomato in Cochise County?"

Using microcomputers (with hard -disk storage), a database is being constructed to store plant disease observations for the Arizona so that we may address these types of questions more easily.

Disease observations come from a variety of sources including extension specialists, departmental diagnostic clinics (Tucson, Phoenix, and Yuma) and extension agents located in all 15 counties. Additional information from founding faculty members is also included in the Arizona Plant Disease

Database. Many types of information are collected including: plant species, disease (s) obeserved, contributing stress factors, geographic location, observation date, estimates of disease severtiy, irrigation and other cultural practices.

Currently, the database holds 5,600 disease observations. When the disease incidence database is fully operational, it will be available via modem access to anyone with a microcomputer. Then, anyone with a question about Arizona plant diseases may be able to obtain in formation using a simple menu -driven query program. As more information is added to this system, researchers will be able to explain the temporal patterns of disease occurrence in the state.

When combined with weather data, it may someday be possible to predict outbreaks of diseases in our crops.

Epidemiology is the study of disease patterns in populations; including the description of disease progress through a field or region and the development of mathematical models to predict disease occurrence. Recently, new statistical techniques (spatial autocorrelation methods) have been applied to the description of the spatial pattern of native, soilborne pathogen, Macrophomina phaseolina, which causes the charcoal rot disease of a wide variety of plants in arid areas. These new statistical methods permit the association of pathogen inoculum patterns with disease occurence patterns.

Crop plants vary in their susceptibility to the charcoal rot fungus, thus it is necessary to establish the threshold level of pathogen inoculum which causes detectable disease for a particular crop.

With an established threshold and a picture of the disease potential, based on inoculum pattern, it may soon be possible to help growers make better planting decisions for specific fields.

Dr. J.D. Mihail

Dr. S.M. Alcorn

Dr. M.R. Nelson

Department of Plant Pathology

Managing Pesticide


As reported in 1985 there are at least

447 species of arthropods resistant to pesticides. In recent years, there have been increasing efforts to come to grips with the spiraling resistance problem and to attempt to initiate methods to manage pesticide resistance. Probably the greatest organized effort to manag(

21 resistance in recent years has come from pest management programs whereby other techniques were utilized, with pesticides being employed as the last resort stop -gaps, thus, reducing selection pressure.

The purpose of this study was to investigate the inheritance of permethrin resistance in tobacco budworm (TBW).

This would permit greater predictability on the possible development of resistance in field populations and perhaps, a means of managing our insecticide use patterns to delay or prevent development of resistance.

The susceptible culture of TBW was obtained from the USDA Western Biological Control Laboratory in Tucson.

The resistant culture originated from a field -collected colony of TBW from Mar icopa County and was subjected to a high level of permethrin pressure each generation. When crosses were made, equal numbers of susceptible and resistant TBW were placed in glass jars for mating and oviposition. Insecticide applications and mortality counts were by a standard method tor detection of resistance in Heliothis using a topical applicator to apply known concentrations of insecticides to individual larvae.

The figure graphically depicts results of topical treatments of permethrin on both susceptible and resistant TBW populations, and on certain crosses. In this graph, the slope of the lines and their position along the horizontal axis give the significance of the response of the TBW cultures to permethrin insecticide. The more vertical lines indicate a more uniform population for susceptibility (S) or resistance (R) while the flatter line (R X F1) represents a population possessing a greated proportion of the resistant (R) genes, in this case by backcrossing R males with F1 females of the SXR pairings.

The study led researchers to conclude:

A. The tobacco budworm has the capacity to develop high levels of resistance to permethrin.

B. There is a dramatic reduction in the LD 50 of FI from either reciprocal cross when compared with that of the R strain.

C. Permethrin resistance is non sex linked.

D. Resistance appears to be recessive and polygenic.

Dr. T.F. Watson

S.E. Kelly

Department of Entomology

Detecting Phytophthora,

The Plant Destroyer

Phytophthora, a Greek word meaning plant destroyer, is a soil -borne plant pathogenic fungus responsible for yearly losses in many fruit tree, vegetable and ornamental crops. In Arizona, this pathogen has been recovered from apple, citrus, jojoba, guayule, alfalfa, pumpkin, chili pepper and several ornamental plants.

Phytophthora kills plants by consuming root and bark tissues. Recovery and identification of the pathogen is essential for accurate disease diagnosis as well as implementation of effective disease control measures. Isolation of

Phytophthora from diseased tissue or infested soil is often difficult, especially when dealing with perennial plants.

The life cycle of Phytophthora is unusual in that this pathogen can produce several different types of spores or propagules, depending upon environmental conditions. In the presence of water, Phytophthora produces sporangia which liberate swimming zoospores.

This phase of the life cycle is stimulated in order to enhance recovery of the pathogen. A trapping technique using pear fruits enables researchers to effectively recover these motile zoospores.

The pear- baiting procedure is analagous to "fishing" for Phytophthora. Diseased tissue or infested soil is covered with water, then pear fruit "bait" is place in the water for two days. If Phytophthora is present in the soil or diseased tissue, zoospores will be produced. These motile spores swim to the pear fruit and infect the fruit tissue. Infection sites on the pear fruit develop into brown spots evidence of a successful "catch ". The pathogen can be readily recovered from the brown spots on the pear fruit.

Dr. Michael E. Matheron

Department of Plant Pathology



What Makes A Pest A Pest?

Aphids are a major scourge of agriculture in all parts of the world, due both to their direct impact on crop plants and to their role as transmitters of debilitating plant viruses. Of approximately 3,000 species of aphids in the world, only about 150 or 5 percent are known to attack crops.

How does an aphid species, initially restricted to a few native plants, become a pest of crops? Part of the answer involves the unusual reproductive mode found in aphids. All aphids are parthenogenetic for numerous generations each year; that is, virgin females give birth to genetically identical daughters in the absence of males. Reproduction without sex gives rise to natural clones each consisting of many individuals with identical preferences for certain plant varieties.

Most pest aphid species have lost the sexual part of the life cycle. They persist as mixtures of relatively few, long -lived clones, also referred to as " biotypes."

Each biotype has characteristic abilities to colonize certain plant varieties and to resist certain insecticides.

In annually sexual aphids, a successful host specialized clone cannot increase indefinitely because it is destroyed by the annual sexual generation. However, in pest species lacking sex, a clone with unusual abilities to colonize, say, a certain alfalfa cultivar or some variety of pecan, can build up in numbers and cause agricultural losses year after year.

In some cases, plant breeders have responded with biotype resistant varieties. For example, alfalfa resistant to biotypes of spotted alfalfa aphid and pea aphid, apple rootstocks resistant to wooly apple aphid, and grape rootstocks resistant to grape phylloxera, a parthenogenetic aphid relative. But new clones arise, either from mutation or from sexual reproduction in part of the population. From this pool of new genetic types, clones able to colonize widely planted "resistant" plant varieties will have an advantage and spread.

Why do pest species tend to lose the sexual generation and spread as large, long -lived clones? Several factors seem to play a role. The sexually produced egg is the most cold -tolerant stage in most aphids, and in warm agricultural areas such as Arizona, this cold tolerance is not necessary to survive winter.

Also, many aphids have the sexual generation on a plant species other than the main hosts on which they become pests; an example is the green peach aphid, perhaps the worst aphid worldwide, which has the sexual generation on peach trees but feeds on potatoes, tomatoes, beets and many other cultivated plants during its parthenogenetic phase.

If the sexual host is absent, only clones which remain parthenogenetic indefinitely will persist. However, the main reason for the loss of sex in crop aphids seems to involve the lower genetic variability in agricultural crops as compared to native populations.


An aphid clone specialized to one widely planted variety can increase faster than a genetically mixed collection of individuals, specialized on a variety of plant types. Tests with sorghum and other crops are being conducted to determine whether plantings of a heterogeneous collection of cultivars would slow the spread of destructive biotypes.

Loss of the sexual stage from the life cycles of aphids on crops is only one example of how pest insects differ in basic biological properties from their non -pest relatives. Clearly, insect populations often undergo genetic change when they shift from initially innocuous nibblers of native plants to agricultural problems. Understanding how agricultural practices affect these changes should aid in controlling incipient pests.

Dr. Nancy A. Moran

Department of Entomology

Whitefly Transmitted


Since 1981, when populations of the sweet potato whitefly reached unparallelled levels in the desert

Southwest and northwestern Mexico, three new whitefly- transmitted plant geminiviruses have been identified as economically important pathogens of irrigated cotton and vegetable crops.

Whitefly- transmitted geminiviruses were previously recognized as pathogens predominantly in tropical and subtropical regions of the world.

Geminiviruses are unique among both plant and animal viruses in that they are composed of paired or geminate particles, a morphology not shared by any other virus group. In addition, they are the only group of plant viruses containing single- stranded DNA as their genetic material. Whitefly- transmitted geminiviruses typically infect plant species within only a few plant families.

Following the 1981 whitefly infestation, there was a renewed interest in the nature of the disease and the casual agent. The cotton leaf crumple pathogen was subsequently identified as a geminivirus which infects legumes as


A microscopic view of zucchini infected with watermelon curly mottle virus.

well as cotton and other malvaceous plants. The results of an extensive field plot /greenhouse study indicated that infection by the leaf crumple virus resulted in yield loss, regardless of plant age at time of infection. In addition, plants infected at later growth stages exhibited a yield reduction even when typical leaf crumple symptoms were not observed.

The 1981 whitefly populations also brought to light two previously unreported geminiviruses of vegetables; the yellow leaf curl or `Chino' virus of tomato, and the watermelon curly mottle virus which infects cucurbits. Tomato plants infected by the yellow leaf curl virus produce blossoms but fail to set fruit; thus the severity of the disease was immediately acknowledged. A breeding program has been established by a U.S. seed company to develop tomato varieties with resistance or tolerance to this virus. The watermelon curly mottle virus causes serious disease of buffalo gourd, muskmelon, pumpkin, squash and watermelon by dramatically reducing fruit set.

Research efforts are currently underway to develop rapid, reliable techniques for virus detection in both plants and whiteflies. The ability to detect geminiviruses in plants will allow for rapid identification of the disease problem and is especially useful when infection by more than one virus occurs in the same plant. Effective diagnostic techniques are required for rapid screening of plant breeding materials, and as epidemiological tools for the identification of geminiviruses in weed and crop reservoirs.

Detection of the viruses in trapped whitefly vectors will allow researchers to study how these viruses spread from weed and crop reservoirs to healthy crop plants.

Dr. J.K. Brown

Dr. M.R. Nelson

Department of Plant Pathology

Curbing The Spread of

Root Rots

Among the more serious problems in forest, shade, and orchard trees and other woody plants are root rot diseases caused by soil -borne Basidiomycetes.

One of the important genera is

Ganoderma, a large genus that includes a number of pathogenic species distributed throughtout the temperate and tropical forest regions of the world. Research on North American species of

Ganoderma has been in progress in the

Department of Plant Pathology for the past four years.

Investigations indicated that six species are represented in the Ganoderma lucidum complex in North America. Two of these, G. tsugae and G. lucidum, occur in Arizona. Ganoderma tsugae decays dead white firs and is apparently not pathogenic. In Arizona Ganoderma lucidum is a common root -rot pathogen on oaks, mesquite, olive, African sumac, and other native and exotic hardwoods.

It is also reported as a pathogen on grapevines in Mexico. Field and greenhouse experiments in Tucson provided evidence that it is pathogenic on grape.

Genetic studies on vegetative incompatibility in populations of G. lucidum show that isolates from closely associated trees are of different genotypes, indicating that basidiospores are responsible for infection and that vegetative spread from one root system to another is not a common means of dissemination of the fungus.

The ability of these fungi to cause selective delignification (stripping) of several kinds of wood outside its natural environment was also determined.

Chemical analyses of decayed wood blocks and controls and ultrastructural changes in wood cell walls as observed with the scanning electron microscope indicated that both species of

Ganoderma are capable of significant selective delignification in grape and oak wood. Delignification in white fir and Douglas fir wood also occurred, but on a smaller scale.


Longitudinal sections through sound, undecayed (A) and decayed (B & C) grape stems. Decay columns are indicated by arrows.

Of the other four species, the one with the most potential in biotechnology is

G. colossum. This is a tropical species. It causes a root and butt rot of hardwoods and has a remarkably high optimum growth temperature of 40 degrees centigrade. It grows at 45 degrees C and survives exposure to 50 degrees C. Further experiments are in progress with this fungus to determine its ability to cause selective delignification and to break down another phenolic compounds at high temperatures.

Dr. R.L. Gilbertson

Dr. J.E. Adaskaveg

Department of Plant Pathology

Texas Root Rot and

Wine Grapes

Studies conducted by the UA Agricultural Experiment Station in the late

1970's showed that Arizona also has the potential of producing truly great wines.

Because of their low water use, wine grapes seem ideally suited to Arizona.


Often vines are grown on land formerly used for pasture or on distressed farm land.

It was recognized very early that the greatest threat confronting the wine grape industry in Arizona was a disease, commonly called Texas root rot, caused by a soil borne fungus, Phymatotrichum omnivorum. This fact became apparent in 1974 when Texas root rot was discovered in grape vines at the Oracle

Agricultural Center.

Early research on Texas root rot of cotton showed that disease did not occur in acid soils and that it could be controlled by acidification of the soil. Since soils at the Oracle Agricultural Center are slightly acidic at the surface and calcareous below two feet, sulfur treatments were applied to the soil in a four foot strip in the vine row. The following year P omnivorum was found on roots of several yellowing plants but vines did not die. Over the next four years all symptoms of disease disappeared. Treated soils remained acidic.

In 1979 commercial plantings in the

Sonoita Basin were also found to be infected. Ammonium thiosulfate applied through drip irrigation was used to acidify these soils. Disease was controlled wherever soils were neutral or acidic, and soil pH in treated areas remains low. Wherever soils are calcareous most plants died.

Work done by horticulturalists in Texas more than 50 years ago indicated that there may be some tolerance to disease in wild grapes. Selections of Vitis champini, Champanel and Dogridge, showed tolerance in field studies. In 1976 a new block of vines was planted at the Oracle

Agricultural Center using Dogridge rooted cuttings that were budded to vin fera varieties. Soils were not acidified.

Two years later, three vines had died of disease. New Dogridge vines were planted at these sites, and after nine years all replacement vines have remained disease free.

The same year, vinifera cuttings were rooted in calcareous soils. Three years later vines began to die from Texas root rot. Dogridge vines were planted in all sites where vinifera vines had died, and to date no Dogridge vines have died from the disease.

Results of field and laboratory research to date indicate that acidification of non calcareous soils and use of tolerant root stocks can result in disease control in some areas. Avoiding the disease by planting in presumably uninfected areas can be very risky unless a previous planting of susceptible plants indicates that the disease does not occur in that specific area.

Dr. Gordon Dutt

Department of Soil and Water Science

Mary Olsen and Donna Goldstein

Department of Plant Pathology



The Economics of Alternative

Irrigation Techniques

Rising energy prices during the 1970's and the passage of the Groundwater

Management Act in 1980 have focused increased attention on efficient water use in Arizona's agricultural sector. As a result, there is substantial interest by growers concerning how they can imtDrove their irrigation techniques through better management and new


An ongoing research program in the Department of Agricultural Economics, in cooperation with the departments of

Plant Sciences and Agricultural Engineering, is attempting to analyze the expected profitability of adopting these new irrigation technologies. Is the grower going to be better off econominvesting in and operating a new irrigation system? To date economic analyses have been conducted for laser leveling, drip, water harvesting and linear -move technologies. An ecolomic analysis of surge -flow irrigation should be completed in 1987. Com-

)uterized models are used to evaluate he rate of return to these investments ender alternative commodity price,

Meld, water savings and investment

ìost assumptions.

several highlights from this research effort are worth noting. First, our anayses have shown that the existing nanagement level is a key determinant n selecting an irrigation technology. It nay not be economically justifiable to nvest in a drip or linear -move irrigation iystem if the existing furrow system is well- managed.

A second highlight is the need to increase yields with the new technology over what they were in furrow irrigation. Water savings alone do not pay for the investment costs of most irrigation systems. More intensive management of fertilizers, insecticides, herbicides and water is required to obtain the necessary increments in yield. An ecogomically significant yield differential lay not be realized when converting om a well -managed furrow system to linear- move or drip system.

Financial considerations are a third highlight. Investment costs of

$400 -$1500 per acre for these alternative irrigation systems will have an impact on the financial status of the firm. Debt financing will increase the growers leverage position and may expose the farmer to increasing financial risks if higher yields do not materialize.

Negative cash -flows attributable to these investments during the first two to three years must be covered by other enterprises in the farm business. The

Tax Reform Act of 1986 will reduce the favorable after -tax impacts of these capital investments because investment tax credit has been repealed and depreciation schedules have been lengthened.

A final point is that although unskilled irrigation labor can be replaced by the capital investment, the increased level of technical management may require an increase in overall management costs. These increased management costs may be represented by the opportunity cost of the grower's time for the salary of an irrigation manager. The new irrigation system may reduce hassles with irrigation laborers but the actual out -of- pocket costs of irrigating may be higher with the new system.

Dr. Paul N. Wilson

Department of Agricultural Economics


Transferring Water Rights

Historically, there was little reason for water markets because appropriation of unclaimed water and subsidized supply development provided low cost water for agriculture, industry and cities.

However, surface water supplies have become fully appropriated in many areas and some states have limited new groundwater pumping so that it is no longer easy to appropriate water. The local costs of water development projects have risen since the federal government is no longer willing to subsidize project costs to the extent it did in the past.

These changes, combined with a gradual shift in the economy of the West from agriculture and mining to municipal growth, industry and tourism have generated increasing pressure for transfers of water rights.

Water markets are distinguished from other property transfers in that water's value is recognized as distinct from the value of land and improvements. Both the public and the private sector participate in western water markets. Water buyers in the western states are often public entities such as cities, state agencies and public utilities.

During the last five years nearly every western state legislature (and court system) has had to address policy issues involving water markets: how can third party and community impacts of transfers be mitigated; should interbasin transfers be restricted; what approval procedures and criteria need to be established to govern transfers; and should individuals profit from selling water?

While water markets can provide incentives for profitable water use and support regional economic development by providing water to new users, transfers may have impacts on neighboring water users, rural communities, water quality, riparian environments and water -based recreation. State policies seek to ensure that third party interests and public values are protected when market transfers occur.


Although market transfers have been occurring in Arizona for many years, the

1980 Groundwater Management Act created a new legal environment for water transfers and water rights sales now occur frequently. The City of

Tucson and several Phoenix -area municipalities have purchased "water ranches ", as have private development and investment firms. Some of these purchases are solely to acquire water rights and the buyer has no plans to develop the irrigated land that must be purchased, under Arizona law, in order to Obtain appurtenant irrigation water rights.

In these situations the total price paid for the property gives a good indication of the value the buyer places on water rights. Purchase prices for water ranches calculated per acre foot of water rights transferable to the buyer have typically ranged between $400 and

$1,200 dollars per acre foot (in constant

1986 dollars) over the years 1970 through 1986. At least 400,000 acre feet of irrigation water rights (including both groundwater and surface water rights) have been purchased for non -irrigation uses through "water ranch" purchases in the last 15 years.

A second type of water purchase is becoming common. Type II non- irrigation groundwater rights were created by the

1980 Groundwater Management Act to formally recognize rights to pump groundwater within Active Management Areas. Unlike irrigation rights,

Type II rights can be bought and sold separately from land and transferred within their Active Management Area of origin.

In the Tucson and Phoenix area, Type II rights typically sell in small blocks of ten to three hundred acre feet per transaction for between $400 and $1,200 per acre foot (in 1986 constant dollars) though there have been a few sales at higher prices ($2,000 per acre foot).

Type II rights are being leased for

$100 -$200 per acre foot per year though state law is ambiguous about the permissibility of leasing Type II rights. Type

II rights represent a small portion of

Arizona's water resources but their location and transferability within active management areas make them an important part of the Arizona water market picture.

Dr. Bonnie C. Saliba

Department of Agricultural Economics

The Japanese Beef Market:

Trade Restrictions and Politics

Declining per capita beef consumption in the United States has caused dramatic readjustment in the U.S. beef production sector and evoked uncertainity about the future of the cattle industry. Arizona has been seriously affected.

In 1970, 860,000 fed cattle were marketed in Arizona. By 1985 that number had declined to 510,000 head. Market development, both domestic and international, has caught the attention of government officials, farm leaders and university researchers who are interested and concerned about the beef industry.

Japan presents an attractive export market. Per capita income is high and growing. Beef has only quite recently occupied an integral part of the

Japanese diet and prospects for increased consumption levels appear good. However, if grey clouds have a silver lining, this silver cloud has two linings of grey.

First, beef imports into Japan are not subject to free trade- import quotas are set and strictly enforced in Japan by a semi- autonomous quasi -public agency, the Livestock Industry

Promotion Corporation (LIPC). Second,

Japanese beef quality standards, trading mechanism, and handling techniques are very different from those in the U.S.

Increased penetration of the Japanese beef market by the U.S. will involve the solution of a myriad of technical, political, and economic constraints. A new

Department of Agricultural Economics project will evaluate the economic magnitude of Japanese beef trade barriers in conjunction with the policy formation process in Japan.

Because Japanese public policy presents the primary constraint to increased beef exports, it is important to have a clear understanding of the nature and causes of the policy. A report, currently in the preparation stage, delineates the

Japanese beef production and consumption sector, trade policies and important components of the political system. Protection levels evaluated using effective protection and tariff equivalent rates suggest that beef producers in Japan benefit from an exceedingly high level of government support.

Research on the causes of policy is proceeding. It is frequently asserted that

Japan provides such substantial protection to its beef production industry because of national food security concerns. However, preliminary evaluation of Japanese protection levels using an econometric model does not support this contention. In contrast, it appears that private interest group articulation and peculiarities associated with

Japanese political institutions provide superior explanations for Japanese beef trade policy.

As this research project proceeds it is hoped that an improved understanding of the Japanese beef market and policy situation will emerge.

Dr. Merle D. Faminow

Department of Agricultural Economics


Arid Lands

Information Center

The Arid Lands Information Center

(ALIC), continues to provide a variety of reference and information management services to individuals and institutions locally, nationally and internationally. Recently, ALIC has focused on providing technical assistance for establishing and improving information capabilities in developing countries.

Projects are underway to assist ministries in the Yemen Arab Republic,

Republic of Niger, Mauritania, Egypt and the Arabian Gulf University in


This type of technical assistance encompasses many activites including:

1) evaluating existing facilities and document collections; 2) compiling reports describing needs and long -range plans; 3) installing microcomputer based cataloging systems; 4) identifying appropriate software for in -house computer systems; 5) developing and implementing policies for acquisition, retention, treatment and circulation of documents and for management and staffing; 6) training personnel to use automated cataloging systems and to implement policies; and 7) developing specifications for construction and furnishing of library facilities.

Since August 1986 ALIC has cooperated with the UA library by providing information and documentation management assistance to Niger's Ministry of Plan. The USAID -funded project, based in the capital city of Niamey, has successfully initiated the reorganization of the ministry's vast documentation resources. All of the activities listed above have been undertaken by the UA team, and long -term implementation now is in the hands of a project- trained professional.

Dr. Robert G. Varady

Barbara Hutchinson

Office of Arid Lands Studies



Agricultural Communications is the communications support unit for the

College of Agriculture's research, teaching and extension activities.

Technological advancements in corn munications equipment, strategy and evaluation are continually monitored and implemented in this support effort by the faculty and staff specialists of Ag

Comm. Over the year, the latest in laser printing and graphics technology have been incorporated into the unit's communications support efforts directed toward desk -top publishing.

Interactive video, which blends video and computer technologies, is being studied as a new medium of information dissemination. Videotape is being applied in the development of instructional and technology transfer programs. New and more effective long distance communications techniques such as satellite teleconferencing are being applied for the exchange of research information worldwide.

As the College of Agriculture moves into the 21st century, Agricultural Communications will begin offering complete interactive audio /video satellite teleconferencing from its communications teleport to be built at the Maricopa

Agricultural Center. This state of the art satellite teleconferencing center will be linked by fiber optics, microwave and

Ku -band satellite to Extension offices and educational institutions throughout

Arizona as well as to other research centers and institutions of higher learning around the globe.

The communications promise of tomorrow led by the technological revolution of today is truly a global village closely linked in an easily accessible and efficient network dedicated to the open exchange of agricultural research data.

Thus communications technology is today already contributing to the basic purpose of academic research.

Larry Klaas

Agricultural Communications

Helping Arizona Grow

The primary objective of the UA Economic Development Program (EDP) is to foster economic development throughout Arizona by making the UAs extensive resources available to organizations and areas that can benefit from job and income creation and job retention efforts.

Co- sponsored by the U.S. Department of Commerce's Economic Development

Administration, EDP conducts applied and basic research studies, provides technical and management assistance services, offers counseling and referral services, and sponsors workshops and seminars. The EDP serves clients in both metropolitan and non- metropolitan areas in Arizona. Clients may include state government, municipal and county governments, community organizations or trade associations and, in some cases, even business and industry and individuals.

When selecting clients and projects, preference is given to those with potential to substantially enhance regional employment and income levels. Many projects, especially short -term projects, are conducted on a "no fee" basis by program staff and consultants. Other projects are conducted on a fixed or variable price cost sharing basis.

EDP staff can help with the "scoping" of problems and approaches to problem solving. Further, as a "point of first contact" within the UA, the EDP is positioned to provide referral services for clients searching for the "right person" to accomplish a job.

Dr. Lay J. Gibson

N. Gene Wright

Office of Arid Lands Studies



Improving Vocational Student Organizations

Vocational student organizations are an integral part of vocational education.

Arizona's Future Homemakers of

America (FHA) and Home Economics

Related Occupations (HERO) allow members to explore their interest in an occupation and to learn and refine leadership, social and citizenship skills.

In an effort to better understand these youth organizations, the School of Family and Consumer Resources conducted a study into the groups' membership, management of chapters, perceptions of achievement of the organization's purpose, and reasons for joining or not joining the organization.

All FHA (49) and HERO (59) chapters affiliated with the Arizona Department of

Education in 1983 were included in the study. This included all FHA and HERO members, their advisors, and a sample of home economics students who were not FHA and HERO members. The FHA members thought their advisor gave moderate importance in getting the respondents to join FHA, whereas there was high importance from HERO respondents to join HERO. The members indicated that their respective organizational name was not a "turn -off" to members. The FHA and HERO members thought that the youth organizations were an important part of the high school program, and the FHA respondents indicated that all home economics students should be a member of FHA. However, HERO members disagreed that all home economics related occupations students should be members of the HERO CLUB.

The FHA and HERO advisors had interesting results as well. They thought the youth organization should be inter grated into classroom activities. In addition, they indicated that all studer should be members of the youth organizations.

There were many differences between those who joined the organization and those who did not. Members indicated that their home economics teacher encouraged FHA or HERO membership.

The majority of members thought that all students should join the organization while the non -members disagreed with these statements. Members responded that their parents thought they should belong to the organization, whereas non -members disagreed. In addition, the members replied that their youth organization goals were important to them.

In general, our results show that the key to an effective vocational student organization is an advisor who is committed to the organization.

Dr. Elizabeth L. Kendall

School of Family and

Consumer Resources

Fashion Help For Arthritis


Today, one out of seven Americans, more than 36 million suffer some form of arthritis. This proportion is even higher in Arizona where the mild climate seems to slow down the progressive nature of this disease and offers them some relief from pain.

When daily living activities are complicated by a physical handicap the challenge of those activities is magnified. That fact became apparent following a 1985 survey of Arizona's arthritics. The 789 respondents cited clothing and dressing problems as one of their common concerns.

Of particular concern to both men and women, those problems relating to feet and footwear -where to get attractive shoes that fit well, feel comfortable and styles that can be easily fastened. Even


M. CULBERTSON if the hands work, their hips or knees may not. This prompted the development of a videotape on "Foot Problems,

Foot Wear and Foot Care" that included interviews with a practicing podiatrist and a certified pedorthist, with special training in fitting shoes for problem feet.

This videotape, along with four others relating to the clothing needs of people with arthritis, form part of a resource center in a local rheumatology clinic plus a larger collection of clothing information at the Harrington Arthritis Research

Center in Phoenix.

Resource centers such as these serve to inform individuals, paraprofessionals and the many professionals in close proximity to clients with daily living needs relative to fashionable clothing.

The collections include displays, literature and references to clothing pamphlets that illustrate how to achieve a simple modification, for example, or catalogs from manufacturers and suppliers, audio -visual materials and actual fashionable clothing items illustrating selective clothing features, modified clothing and a collection of possible dressing aids.

Dr. Naomi A. Reich

School of Family and

Consumer Resources

Keeping The Elderly In Shape

Due to the large number of aging persons in our present population and the even larger number expected in the future, quality of life among the aged has become an important area of study.

Retirement is one of the most important events in the life of an aging

American. After retirement, how an aging person spends his or her time in relation to social interactions and the person's own physical care is important.

As part of a larger research project

Susan Blommer, Dr. Donna Iams and

Dr. Mari Wilhelm from the School of

Family and Consumer Resources, selected to study the factors affecting the aged's participation in group fitness activities. The sample consisted of 163 retired or semi -retired people age 55 to

91 living in Tucson. Results of the study suggest that gender does influence the older person's participation in group fitness activities. Women in this study were more likely to participate in such events than were men. However, the men were more likely to spend more hours per week in the actual activity.

Marital status was found to have a positive relationship to group fitness participation. The married person was more likely to be a participant than the single person. A significant number of married fitness participants were not necessarily involved in the same activity as their spouse. For the married respondents the greatest impact on participation was the health of the spouse rather than their own health. If the spouse was in poor health, the respondent was less likely to attend group fitness activities.

The study also indicated that pre- retirement occupation plays a role in group fitness participation. It indicates that white collar workers are less likely to participate than are blue collar workers.

However, if they did participate they spent more hours per week involved in the activity than did the blue collar workers.

Future analysis will focus on the impact of income, satisfaction with participation, and self -perception in relation to group fitness participation.

Dr. Donna R. Iams

School of Family and

Consumer Resources



Promoting Cattle Weight Gain

Growth -promoting compounds which can be implanted in the ear of a suckling calf to increase weight gain have been around for years. Though the efficacy of these materials has been demonstrated by trials on thousands of calves around the country and their use approved by the FDA, many stockmen are still passing them up and missing out on extra weight gain and profit.

The Cooperative Extension Service initiated a four year study in 1983 using three well -known implant products to emphasize the importance of the use of implants as a management tool and to evaluate their effect on weight gain in suckling calves. To be effective, the practice of implanting must be done correctly.The technique used to place the implant "pellets" subcutaneously in the animals ear is critical to good results. The implant must be inserted correctly and in the right location.

During the last four years more than

1,700 calves representing a wide range of straightbred and crossbred cattle were implanted on 20 different ranches in the five northern counties of Arizona.

Test calf groups varied from 40 to over

100 head on different cooperator ranches. Trials started during spring round -up each year with the random selection of equal sized groups of steer calves, depending on the number of products to be tested plus a comparable group of "control" calves. Each animal was ear tagged, implanted or not depending on whether it was used for control, weighed individually and then turned back with its mother. Later in the year, during fall roundup, tagged calves were identified as to treatment and reweighed individually. Animal performance and response to implants was


Added Weaning Weight of Implanted over

Non -Implanted Nursing Calves






4 Yr


Ralgro (lbs.)






Compudose (lbs.)






Synovex- C(lbs.)






measured by a comparison of weight change during the five to six month period between spring and fall roundup.

In 1983 and 1984 test calves were implanted with two leading products,

Ralgro or Compudose. Ralgro contains the synthetic estrogenic agent zeranol.

This compound like many other anabolic substances stimulates the pituitary gland to produce increased amounts of the growth hormone somatotrophin.

Compudose is an anabolic substance designed to release small amounts of the steroid estradiol into the circulatory system, which also stimulates the pituitary gland to produce increased levels of the hormone somatotrophin.

In 1985 a third implant product Synovex-C became available for use in pre weaned calves. This product contains estradiol plus another steroid hormone progesterone. As with the other products, these agents also act to stimulate the production of increased levels of somatotrophin. All of these implants were used in field trials in 1985 and


The table below summarizes the additional weaning weight recorded for calves implanted with either Ralgro,

Compudose or Synovex -C over non -implanted control calves during the four year study. With the exception of 1983, approximately the same number of animals were implanted each year.

Manufacturers of the implants used in these trials indicated various duration's of response ranging from 90 to 200 days; these claims were neither confirmed or unconfirmed in the study.

Considering the price of 450 -500 pound steer calves and the added responses indicated during the test period, implanted calves accounted for an average added net return of between

$3.88- $14.69 per head as compared to non -implanted cattle.

Edward A. LeViness

Area Livestock Specialist

Cooperative Extension Service

Disease and Cattle


Infectious diseases are a major reason for poor reproductive efficiency in cattle, both as a cause of infertility and as a cause of abortion. For the last three years, the Veterinary Diagnostic Laboratory has been conducting systematic investigations for the presence of infectius agents in all samples submitted to the laboratory in cases of bovine perinatal death losses (abortions, stillbirths and mortality of the newborns). The majority of specimens have been from dairy herds in central Arizona, but a sizeable amount of cases have been from beef herds in other areas of the state.

Most of the infectious agents universally recognized as capable of producing abortion, ranging from the very common (Campylobacter fetus,

Trichomonas fetus or IBR virus) to the very rare (Trypanosoma theileri) have been found, as expected, to be present in Arizona cattle. One unexpected finding was, however, the diagnosis of a very high relative incidence of chlamydial infections in aborted, stillborn and newly born cattle.

Chlamydia are unique micro- organisms that have gained considerable attention in recent years. There are two species in the family, Chlamydia trachomatis and

Chlamydia psittaci. While the former primarily infects humans, the later infects a large number of avian and mammalian species, including man.

The strains infecting cattle can produce abortion, stillbirth and neonatal disease, as well as pneumona, arthritis, encephalitis, intestinal and conjuctival infections in this species.

Chlamydial infections are not routinely diagnosed in many diagnostic laboratories because the diagnosis is tedious, time consuming and requires specially trained personnel. As a result, the true incidence and economic importance of these diseases in cattle are largely unknown throughout entire regions of the country.

Our studies in Arizona have shown that chlamydias are the infectious agents most commonly isolated from aborted or weak newborn calves in the state, and that they are almost always part of the complex flora of bacteria and viruses infecting young dairy calves in the first few weeks of life.

Research efforts are now underway to better characterize the epidemiology and all disease conditions associated with these agents, as well as to examine the relationship between the infection and nutritional and management factors in the actual production of the clinical disease.

Dr. Carlos Reggiardo

Department of Veterinary Science


Fertility Warning Lights

Almost all U.S. dairy cattle are bred by artificial insemination. Successful breeding requires special training and skill, not only in "how" but in knowing

"when" to breed. Cows have a period of fertility which lasts about 12 hours and occurs about every 21 days when not pregnant. The age of electronics has provided a potentially effective aid to dairy operators by alerting them with a flashing red light each time a cow is in estrous, or fertile for breeding.

The electronic device, strapped to the rear ankle of a cow, monitors her activity level. We know from observation and have documented with the use of mechanical pedometers like the one hikers wear, that when a cow comes into estrus, she is much more active or fidgety. Its activity rate, or number of movements during a given period of time, will increase by a factor varying from about two to eight times. The electronic estrus detector measures this activity and signals when a cow is suddenly more active than she has been.

The detector, still in development stage, contains a mercury switch which closes a circuit each time a cow moves a leg.

The electronic circuit includes a microprocessor which counts and records each time the switch is closed. At the end of each hour, the average activity rate, in number of switch closures per hour, during the immediate past 12 -hour period is compared with her normal rate, or switch closure rate prior to that

12 -hour period. Thus each cow sets its own standard rate for comparison. This is necessary because some cows are normally much more active than others.

Whenever a comparison shows a doubling in activity rate, a small red light in the face of the detector package flashes, alerting the herdsman that this cow has been at least twice as active as she was during the past two days and may be in estrous. If the cow is three times as active, a second red light flashes; and a quadrupling of activity will flash a third light. When a herdsman sees one or more red lights, he can use the cow's record in conjunction with the other signs and characteristics he has learned to recognize in cows in estrous to determine whether or not the cow is experiencing a fertile period and should be bred. These other signs are often too subtle to spot in a large group of cows, but the flashing light calls attention to any cows that should be examined more closely.

We have learned that a tripling of activity rate, or two lights flashing, quite surely indicates a cow in estrous. We also know that almost all cows will at least double, but may not triple their activity rate, so some cows will never shine the second light. And there are also occasions when cows, for other reasons, may temporarily become twice as active without the presence of estrus.

Thus, one light may or may not be a positive signal for fertility. We are currently seeking a single multiplier, perhaps 2.7, that will be exceeded by all or almost all cows when in estrus, but will seldom occur from other causes of activity increase.

With the single multiplier properly identified and incorporated into the circuitry, and a single flashing red light externally visible on a unit mounted on the ankle of a cow, a herdsman can readily pick out from a large group of cows the ones that are currently fertile and should now be inseminated. He simply walks through the "red light district" where potentially fertile cows are located and more closely examines the ones flashing their red light.

Dr. Frank Wiersma

Department of Agricultural Engineering

Dennis V. Armstrong

Department of Animal Sciences

Detecting Water Borne


Cryptosporidium is a newly recognized enteric dwelling parasite that causes diarrhea in several animal species including man. Infections appear to be especially prevalent among children, immunocompromised individuals and travelers. This infection also occurs with frequency in workers affiliated with the dairy and calving industries. This latter point underscores cryptosporidium's zoonotic potential since numerous mammalian species apparently can serve as reservoirs of human infection.

While knowledge of the epidemiology of this organism is limited, transmission by contaminated water has been implicated. Giardia is currently the most commonly diagnosed intestinal parasite by public health laboratories within the

United States. Giardiasis is becoming a real health concern to the recreational public and to individuals living in communities served by inadequately treated surface water.

A survey in Arizona was conducted to determine the prevalence of Cryptosporidium and Giardia in surface waters. Sites were selected with input from the U.S. Forest Service, Bureau of

Land Management, the Navajo Nation

Department of Water Management and the Arizona Department of Health Services. A total of 71 surface water sites were tested in 1986.

Water was collected using procedures recommended by the U.S. Environmental Protection Agency. Collected effluents were centrifuged and direct smears of the pellets were made and heat fixed.

Monoclonal antibodies to Giardia and

Cryptosporidium were used to detect parasites in indirect or direct immunofluorescent assays using epifluorescence.

Monoclonal antibodies (MAbs) specific for Giardia and Cryptosporidium cell wall determinates were developed in our laboratory for the detection of these parasites using immunofluorescent assays. The Cryptosporidium monoclonal has been licensed and will soon be in

33 commercial production. The Giardia monoclonal is in the process of being licensed and will also be in commercial production in the near future. These new reagents greatly enhance the ability to more accurately and rapidly detect these two, sometime elusive, parasites,

Data from the sampling of 71 surface water sites throughout the state indicates that 28 percent of the sites were positive for the presence of Cryptosporidium oocysts and 5.6 percent of the sites were positive for Giardia cysts.

The significance of these organisms in surface water needs to be evaluated.

Nine Cryptosporidium positive sites were resampled and found to be negative. This may indicate that

Cryptosporidium is a seasonal parasite in surface water. More data is needed, however, to substantiate this.

Dr. Charles R. Sterling

Marilyn M. Marshall

Department of Veterinary Science

How Bacteria Produce


Corynebacterium pseudotuberculosis produces disease in domestic animals and occasionally in humans. The most common syndrome is caseous lymphadenitis of sheep and goats which is usually characterized by abscessation of superficial lymph nodes, following introduction of the bacteria into abrasions or wounds. Infections occasionally disseminate, resulting in development of abscesses in visceral organs and subsequent death of the animal. Most of the economic significance of caseous lymphadenitis is due to decreased milk production, condemnation of meat at slaughter, or decreased value of wool, hair and hides.

Horses and cattle also become infected with C. pseudotuberculosis, usually resulting in formation of superficial abscesses which have the potential for iissemination. Human infections are

.usually in individuals involved in handling infected animals.

Our research group is involved in explaining the mechanism by which bacteria produce disease in animals.

Corynebacterium pseudotuberculosis has been of special interest because of the opportunities it has provided for both basic and applied research. Developing a more clear understanding of a basic host: parasite interaction has yielded information which will be useful in solving a health problem faced by sheep and goat producers worldwide.

Attempts to characterize isolates of C.

pseudotuberculosis obtained from domestic animals throughout the world revealed an unexpectedly high level of heterogeneity, suggesting that within species differentiation of the organism might be in order. The characteristic which was most consistent in separating the organisms into groups was the ability or inability to produce nitrate reductase, an enzyme which is part of a system for generation of energy when the organism are cultivated in the absence of oxygen. It was found that isolates obtained from horses were usually able to reduce nitrate (95 percent), while those from small ruminants could not do so (97 percent).

To determine if genetic differences could be demonstrated, DNA was isolated from each culture and examined by restriction endonuclease analysis, a technique in which the chromosome is enzymatically digested and the resulting fragments separated by electrophoresis. The correlation between the two grouping methods was

100 percent. An alteration in the taxonomic status of Corynebacterium pseudotuberculosis has been proposed, suggesting the establishment of biovars equi, for those isolates reducing nitrate, and ovis, for those isolates unable to do so.

The importance is these findings goes beyond the field of bacterial taxonomy.

Since all the isolates in this species are very much alike (with the exception of the ability to reduce nitrate), the factors responsible for the differential host preference are probably few in number; further detailed comparisons should reveal their identities. This will allow the development of prevention and control strategies directed at specific microbial targets. In addition, differential host preference based on such minor differences is a very rare situation. These findings may be of broader significance for the overall study of pathogenesis of bacterial disease.

All isolates of C. pseudotuberculosis produce a toxic phospholipase D (PLD), an exotoxic enzyme which we have shown to be important in initiation of infection.

PLD damages white blood cells, allowing the organism to multiply immediately following entry to the host, and producing an immunocompromised state in chronically infected animals. Improved methods for purification of PLD from cultures of C.

pseudotuberculosis developed by our group have greatly facilitated study of the enzyme and its role in disease. We have also cloned the PLD gene into E.

coli and are now characterizing it.

The results of this part of our research program are important for several reasons. The importance of PLD in the disease process suggests that it could be a focus of vaccine development efforts, perhaps a genetically- engineered product. Information from study of the genetics and molecular biology of PLD production will also expand our understanding of other proteins, including their synthesis, control of synthesis, export, and structure: function relationships.

Since its target substrate is sphingomyelin, an important phospholipid constituent of mammalian cell membranes, PLD may also prove useful as a probe for study of the biology of membranes.

Finally, corynebacterial PLD is strikingly similar in biological and physical properties to the venom PLD responsible for the lesion in bites by the brown recluse spider, Loxosceles reclusa. It may be that information on corynebacterial

PLD can be applied to amelioration of the effects of envenomation by the spider.

Dr. J. Glenn Songer

Department of Veterinary Science

35 period. In general, the growth regulator reduced terminal growth and subsequent tree size, increased yields but reduced nut size. The apparent advantage of this growth regulator is maintenance of tree size allowing for a larger number of trees to be planted per acre resulting in increased orchard management efficiency.

Irrigation experiments related to water use and scheduling were established in 1986. This long term project resulted in some preliminary information indicating that too much water

(irrigation frequency too close together) or water stress can reduce yields by increasing premature nut drop or reducing nut size. This experiment will be continued to provide the necessary frequency and amounts of water needed by pecan trees to maximize yields.

Some long term projects were established in 1986 including a grape rootstock trial for determining Texas root rot resistance and a pistachio rootstock trial for determination of

Verticilium wilt resistance, yield potential and cold resistance.

Dr. Michael W. Kilby

Department of Plant Sciences

How Hot Weather Affects

Vegetable Seeds

High temperatures often limit production of vegetable crops in arid environments such as Arizona. They have their greatest effect at different stages of development for each vegetable. High temperatures may inhibit germination resulting in poor stand establishment as often occurs in lettuce. It may also decrease flowering and fruit set in plants like beans, peppers, and tomato. High temperature may stimulate bolting which is desirable when striving to produce good quality lettuce or spinach. And they may also cause poor plant growth or plant quality in vegetables like cauliflower, sweet potato and corn.

Our research focuses on trying to understand what mechanisms are correlated with the degree of heat sensitivity in a given crop. In lettuce and tomato we have identified cultivars with widely differing sensitivities to heat during germination, based on both laboratory and field tests. We are comparing different physiological responses in the sensitive vs. tolerant cultivars.

Some of the responses we have been measuring include synthesis of heat shock proteins, membrane permeability, vigor as measured by root length, and rates of germination. If a parameter is found which correlates well with heat tolerance of a plant, this parameter might be useful as a tool for plant breeders to use in their selection of heat tolerant cultivars.

Seed vigor in response to high temperature during germination varies greatly from one seed lot to the next, depending on when and where the seed was produced. We are investigating how the seed's response to high temperature during germination is affected by the temperature during seed development.

High temperatures, for time periods as short as one hour have significantly reduced both seed set and seed size in lettuce.

Studies to determine causes for these reductions are underway. Also the vigor of the smaller seeds which did set at the high temperature is being evaluated.

Eventually we hope to increase our overall understanding of how high tern peratures during seed development affect the quality of seed and its ability to germinate and establish a vigorous stand with high temperatures.

Dr. J.M. Kobriger

Department of Plant Sciences

Computerized Cotton


Microcomputers have become an important tool on many farms for maintaining financial records and inventories. New developments in computer software may soon make the computer an indispensible tool for crop management as well.

The cotton farmer faces critical decisions daily during the growing season which require a vast wealth of experience. When to plant, irrigate, fertilize, apply pesticides, and when to terminate and harvest are among the events which must be scheduled. These decisions have become more complicated in recent years due to the increased costs of inputs in relation to economic returns for the crop.

Comax /Gossym is a computer system program developed by the USDA, to assist growers in the decision making process. Comax, an expert system, is a computer program with the capability of making decisions similar to those which would be made by an expert cotton grower. It makes the decisions based on a series of facts and rules programmed into it. Gossym, the other half of this team, simulates cotton growth using actual data collected from the field throughout the season and historic weather information to project until harvest.

Comax /Gossym assists growers in making management choices and then predicts the impact of the decision on yield. It allows the grower to pose a series of "what if" questions when faced with choosing a successful management strategy. This program and cotton management expert systems being developed in California and Texas, are evolving with improvements and additions being added continually.

An interdepartmental group in the

College of Agriculture is testing and evaluating Comax /Gossym to determine if this system, developed in the southeastern portion of the cotton belt, is suited for Arizona conditions. Initial tests indicate that it can be adapted.

Dr. W.C. Hofmann

Department of Plant Sciences

Dr. J.C. Wade

Department of Agricultural Economics

Dr. P.W. Brown

Department of Plant Sciences

Dr. D.L. Larson

Department of Agricultural Engineering


Reducing Evaporative Losses

A primary goal of irrigated agriculture is to maximize the fraction of total applied water that is used directly by plants for transpiration, growth, and yield. An important way for irrigation managers to achieve that goal is to reduce evaporative losses from the soil. In Arizona significant evaporative losses can occur from soils, particularly early in the season when plants are small and moist soil surfaces are exposed to large amounts of radiant and thermal energy available for evaporation.

Increased use of drip irrigation in Arizona has helped to reduce evaporative losses from a variety of crops such as cotton, lettuce, and grapes. Properly managed drip irrigation tends to reduce soil water evaporation by restricting the application of water (via small tubes) to relatively small soil volumes and thus minimizing the surface area of moist soil exposed to energy available for evaporation. In contrast to conventional furrow or flood irrigated fields which tend to wet most of the soil surface area, drip irrigated fields tend to appear as a patchwork of isolated wet areas surrounded by dry soil.

The reduction of evaporation from drip irrigated fields relative to that from conventional irrigated fields has not been fully quantified. Measurement of evaporation from non uniform irrigated fields is difficult, and research is being done in the Department of Soil and Water Science to develop reliable methods for that purpose. Two possible methods that are being developed include a micro -lysimetric method and a soil surface temperature- energy balance method.

Preliminary results obtained with these two methods at the Campus Agricultural Center indicate that as much as

33 to 40 percent of water applied to a dry bare soil surface via a single drip tube may be evaporated within seven days following application. These results indicate that evaporative losses from a sparsely vegetated drip irrigated field may be larger than previously thought, and may be due to enhanced evapora-

L. G. KETCHUM tion resulting from advection of energy from the surrounding dry soil to the isolated moist areas within the field.

Not all evaporative losses are considered unbeneficial to irrigated crop production. Soil water evaporation helps to cool air and plants, and thus reduce soil water losses due to transpiration. It also helps to cool the soil, which during the warm season, may aid in seed germination and root development.

Soil /plant /microclimate models are being developed to help manage the role of soil water evaporation in crop production. These models may help bring about improvements in irrigation and crop cultural practices for various crops grown in Arizona. For example, the models may aid in determining irrigation designs and soil surface shape configurations that minimize total evaporative losses, yet maximize the evaporative cooling of seeds and seedlings of strongly temperature sensitive crops such as vegetables.

Dr. Allan D. Matthias

Dr. Arthur W. Warrick

Department of Soil and Water Science

Measuring Water Stress With

Infrared Thermometry

Typical irrigation scheduling techniques have relied on indirect methods to determine when a crop needs to be irrigated. These methods included soil moisture measurements, estimated evapotranspiration, crop color, crop growth patterns, and fixed schedules.

Direct indications of plant water stress have required difficult measurements of leaf water potential, leaf transpiration rates or stomatal resistance.

The U.S. Water Conservation Water

Laboratory in Phoenix has developed a promising technique using infrared thermometry. The technique, termed the Crop Water Stress Index (CWSI), uses infrared measurements of crop canopy temperature and air moisture content above the crop. As developed, the CWSI is zero for a well watered non stressed crop and increases to one for a nontranspiring water stressed crop.

For the last two years cotton yields and water use have been compared to CWSI values. A study at the Campus Agricultural Center in 1986 is typical of the results obtained. Three stress levels were established which were irrigated when the the average CWSI value reached a predetermined point. The actual seasonal values at irrigation were

0.11, 0.21, and 0.30. The corresponding lint yields were 1,180, 1,290 and 1,400 pounds per acre with total seasonal water deliveries of 48.5, 37.4, and 33.3

inches, respectively. This shows that some crop stress increases lint yield.

Also of significance is that maximum yield did not have the highest water use.

Based on these data and additional studies, scheduling irrigations when the CWSI value approaches 0.3 will give the highest yield. This provides a simple criteria which can be used to schedule irrigations for maximum yield. Normally irrigation need can be predicted two to five days in advance which allows time to schedule water delivery.

In addition relationships among yield, stress, and water use can be used to economicaly optimize irrigation scheduling. Similar criteria are being developed for wheat, watermelon, and pecans.

Dr. Delmar D. Fangmeier

Department of Agricultural Engineering

Dr. Donald J. Garrot, Jr.

Department of Plant Sciences

Stephen Husman

Department of Agricultural Engineering


Mechanized Irrigation


The use of surface drip irrigation systems on row crops requires the annual installation and retrieval of the laterals, to permit essential farming operations such as harvesting, tilling and planting to take place without damage to the tubing.

Several different implements are used to mechanically install and retrieve drip irrigation laterals. Installation implements generally travel along the planted rows unrolling tubing from reels and placing it on the soil surface. In contrast, tubing retrieval equipment remains at the field edge, where the tubing is attached to a reel and mechanically pulled from the field.

Meld evaluation of available equipment showed each to have one or more limtations that tended to make it

Somewhat unacceptable. Some of the problems were: high labor requirements (up to six workers for a three -reel system), low effective field capacities

(ranging from 3.7 to 84 acres per hour), relatively high operator skill requirements, and high capital investments since two implements are required (one for installing and one for retrieving).

Because of these inadequacies a project was initiated to develop handling implements for both the small and large reel systems. The specific objectives were: to design an implement for each reel size which could be used for both installation and retrieval, to reduce labor requirements and to increase field capacities.

The small reel implement is shown in

Figure. 1. The design differs from existing implements in that the reel rotates on a vertical axis and was constructed with a tapered core rather than a cylindrical

)ne. The bottom end of the reel was

Jermanently attached to the base of the tone while the top was removable to alow mounting and removal of the tubing oils. A hydraulic motor powered the

.eel during tubing retrieval, with the

,peed set using a flow control valve.

) uring installation the reel was discon-


Figure 2.

nected from the motor with a simple drum brake system was used to control reel speed. A reuseable wrapping tape was employed to hold the rolls together when they were removed from the implement.

Field evaluation of the implement showed performance to be very satisfactory for both installation and retrieval of surface irrigation laterals. A single operator was able to install or retrieve tubing at twice the rate of existing implements.

The large reel implement is shown in

Figure 2. A system which unwound tubing at a rate equal to the distance travelled was developed to eliminate manually staking the tubing to the soil surface. The system consisted of a pair of ground driven wheels which formed a frictional pulling device through which the tubing passed. A 12 V starter was used to rotate the pulling wheels and feed out extra tubing at the field ends. A hydraulically powered cutter severed the tubing when needed. An automatic reel braking system prevented reel velocity from exceeding implement forward velocity, eliminating the need for workers to ride on the implement.

The wheels were also used for lateral retrieval, with power being supplied by a hydraulic motor. Limiting the pressure prevented excessive force from being placed on the tubing when it was pulled from the field, thus preventing tube damage. Since the wheels replaced the reel used on previous machines as the pulling device, the tubing was no longer wound on the reel under tension. This eliminated tube separation at emitters when it was pulled from the field on a warm day, cooled and contracted. A speed control system was utilized to facilitate winding of the tubing on the reel at a rate equal to retrieval from the field, and to compensate for changing roll diameter.

Field evaluation of this system demonstrated that one implement could be used for both installation and retrieval of drip irrigation laterals, thereby reducing capital investment. Increased capacity combine with reduced labor requirements permitted a single worker to install or retrieve laterals at the rate of

2.5 acres per hour, compared to conventional implements which operated from approximately 1 to 2 acres per hour per worker.

Dr. Wayne Coates

Department of Agricultural Engineering


Ag Programs Stretch


International activities of the College of

Agriculture are conducted in order to improve the base of knowledge that UA scientists can utilize to solve agricultural problems in Arizona. When deemed to be important and advantageous the UA enters into long -term relationships with foreign institutions. On other occasions individual UA scientists make the world their laboratory and conduct research on an individual basis.

Arizona farmers have seen many changes in production methods and the introduction of new crops to the state.

Most likely the future will bring more changes than the past. The problems we face in the arid Southwest are similar to those that farmers must deal with in many parts of the world. Currently, the UA is conducting three multi -year projects in arid regions.

In the Cape Verde Islands, off the coast of West Africa, the UA is helping to establish an agricultural research institute.

In Lesotho, a country totally surrounded by The Republic of South Africa, UA personnel are working in the areas of vegetable production, improvement of breeds of sheep and beef cattle (based on local breeds), range management techniques, and agro- forestry. In

Mauritania, situated in the Sahara Desert on the western coast of Africa, UA personnel are studying the complex social interactions involved in trying to bring agricultural change to a region.

And in Portugal UA Agricultural Economics faculty members are assessing the impact of national policies on agricultural production.

College of Agriculture scientists travel to numerous conferences and symposia around the world each year to gain the most current knowledge on a variety of agricultural topics. In recent months faculty members have traveled to Mexico to work with one of the top recombinant DNA experts in the world, tested new detection methods in Peru for identifying the causes of diarrhea in animals, and met with Japanese counterparts in order to analyze trade issues and production marketing and distribution in the beef industry. In January of this year, eight UA faculty members traveled to Cairo, Egypt to participate with experts from around the world in the Second Desert Development Conference. Other activities have been conducted in Brazil, China, Eucador,

Jordon, Kenya, Philippines, Senegal and Turkey.

Michael Palmbach

International Programs

"Eye In The Sky"

Inventories African


As part of a program to develop an effective, responsive research establishment in West Africa's Mauritania the

Arizona Remote Sensing Center has developed new ways of using conventional video and 35mm cameras to help characterize current agricultural practices along Mauritania's Senegal

River. The aerial reconnaissance is done in support of an intensive ground survey.

The aerial reconnaissance was done in two phases. In the first phase, the aerial reconnaissance team flew along the river in a light aircraft and acquired continuous oblique video images out the window. When they landed, members of the ground survey team were able to review the video tapes and select 35 villages for intensive study. Later, the ground survey team visited each village and conducted interviews with farmers and local officials.

In the second phase of the aerial reconnaissance, the team mounted two

35mm cameras and one video camera on a specially- designed camera mount.

With this mount, the team was able to swing the camera array out of the aircraft door and take vertical pictures.

Objects on the ground, such as agricultural fields, could later be measured on these vertical photographs.

Each of the two 35mm cameras carried a different lens. One had a 28 mm wide angle lens that provided a view of a large area. The other was a 135 mm telephoto lens that gave a very detailed view of a small area. With these photos, the team was able to measure agricultural plot sizes, village areas, and plant densities within individual fields.

The team also made estimates of population and relative village wealth by counting the number of buildings in a village and noting the types of roof materials that were used (i.e. mud, thatch, metal or tile).

The video camera and monitor were used to help guide the airplane over villages. The video tapes were used later to help index the 35mm photographs.

Dr. Charles Hutchinson

Arizona Remote Sensing Center

Office of Arid Lands Studies


LAPIS Project Aids Lesotho

Approximately the size of Maryland,

Africa's Lesotho has the distinction of being the only country in the world which is entirely 5,000 feet or more above sea level. Only 13 percent of the country's land area is arable. This land base, which is the home of 90 percent of Lesotho's 1.4 million people, is under considerable production pressure which results in overgrazing and soil erosion.

With the drought in the 1980s has come decreasing per capita productivity and an increasing number of landless persons. Added to this is the fact that

Lesotho is the only country in the world completely surrounded by another country. Lesotho lies wholly within the borders of the Republic of South Africa.

Opportunities for a brighter future rests in the hands of the people of Lesotho, and their success in improving agriculture production. The hope for the future is for the 250,000 men who are currently working in the mines of South

Africa to return to productive agriculture work in their own country.

The College of Agriculture is involved in helping people of Lesotho lessen their dependency on South Africa as a supplier of food. The UA is the lead university for the U.S. Agency for International Development (USAID) Lesotho

Agricultural Production and Institutional

Support (LAPIS) project. LAPIS is designed with three interrelated components: production, research and education. Goals of LAPIS include self- sufficiency in food production, increasing rural income, decreasing unemployment, increasing the nutritional standard, and improving the ability of the government of Lesotho to provide services to their farmers.

Michael Palmbach

International Programs

Rural life in Africa's Lesotho.


Senegal Farming Research

A multi -disciplinary team of 16 scientists from the Office of Arid Lands

Studies, the UAs Environmental Research Laboratory and the Bureau of

Applied Research in Anthropology conducted a rainy season farming systems reconnaissance survey along the

Senegal River in West Africa.

The primary objective of this study was to provide information on the farming systems found in the Middle Valley of the Senegal River to help concerned national and international agricultural development organizations establish research priorities for a research statior at Fanaye.

Several hundred farmers were contacted and indepth interviews were conducted with more than 60 farm families. In addition, general inquiries were directed to several hundred women in 12 villages regarding food consumption patterns. Rainy season data were collected on cropping patterns (irrigated and rainfed), animal husbandry, off -farm economic activities, marketing and consumption.

The study, funded by the U.S. Agency for International Development (USAID) under the auspices of the Senegal Agricultural Research Project II, also focused on some of the key constraints facing farmers in this region of the river basin.

This information provides a basis for orienting research to the needs of farmers.

Dr. Timothy R. Frankenberger

Office of Arid Lands Studies


Research Sponsorship

Fiscal 1986


Total College of Agriculture

Sponsored Research Funding

Federal Government


Individuals -

Private Gifts


Other Educational



State Government








Local Government


1983 1984



million million


$ 7.0





Sponsored Research Funding Breakdown Fiscal 1986




Art Director


Circulation Manager


Arizona Land and People (ISSN 0033 -0744) is published quarterly by Agricultural

Communications, College of Agriculture, University of Arizona, Tucson, Arizona 85721.

Second -class postage is paid at Tucson.

The College of Agriculture includes the School of Family and Consumer Resources, the

School of Renewable Natural Resources, the Office of Arid Lands Studies, the Agricultural Experiment Station, the Cooperative Extension Service, and Resident Instruction. It is an equal opportunity employer.

Subscriptions are free on request. Letters to the editor are welcome. Information in

Arizona Land and People becomes public property upon publication.

It may be reprinted, provided that no commercial endorsement is implied.

Please credit authors, photographers, this magazine and the university.

Dean: Eugene G. Sander. Editorial Board: Kennith Foster, Larry Klaas, Roy Rauschkolb and George Ware.



College of Agriculture

The University of Arizona

Tucson, Arizona 857? 1


assageofthe Federal

"Hatch Act"

created state agricultural experiment stations within the land-grant institutions-establishing the research base for scientific agricultural research.



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