Effects of Sewage

Effects of Sewage
104
Desert Plants 8(3)
Effects of Sewage
Sludge on Yield and
Quality of Wheat
Grain and Straw in an
Arid Environment1
1987
Abstract
A 6 -year experiment (1978) through 1983) was conducted at
the Mesa Agricultural Center, Mesa Arizona, U.S.A. to study the
effectiveness of dried sewage sludge as a fertilizer source for the
production of grain and straw from 'Zaragoza' wheat (Triticum
aestivum L.). Three fertilizer treatments were applied each year
before planting on a laveen loam soil, a member of the coarse loamy, mixed, hyperthermic Typic Calciorthids. The treatments
consisted of: (1) suggested rates of nitrogen (N), phosphorus (P),
and potassium (K) in Arizona -160, 81, and 0 kg ha -' of N, P205,
and K20; respectively; (2) 10 Mg ha -' of dried sewage sludge to
supply N in amounts equal to the suggested rate; and (3)
inorganic fertilizer to provide N, P, and K in amounts equal to
those applied in the sewage sludge -160, 310, and 36 Kg ha -' of N,
P2051 and K20; respectively.
A. D. Day!
Department of Plant Sciences
University of Arizona
R. K. Thompson
Department of Plant Sciences
University of Arizona
Average number of days from planting to harvest, plant
height, grain yield, grain volume -weight, and grain /straw ratio
were similar for wheat grown with all fertilizer treatments. In
vitro dry matter disappearance (IVDMD) and total protein
concentration in wheat grain were similar for all fertilizer
treatments. In vitro dry matter disappearance and total protein
concentrations in wheat straw grown with sewage sludge alone
were higher than they were in straw from wheat grown with
suggested N, P, and K from commercial fertilizer. Wheat grain
and straw from all fertilizer treatments contained relatively low
concentrations of cadmium, zinc, copper, lead and nickel.
R. S. Swingle
Department of Animal Sciences
University of Arizona
Concentrations of N, P, K, Na and total soluble salts were higher
in soil fertilized with dried sewage sludge for 6 years than they
were in the original soil.
Additional Index Words: Municipal wastes, pollution, fertilizer,
environment, livestock feed, soil fertility, soil amendments,
heavy metals.
Literature Review
Most major cities have sewage processing plants which
produce large quantities of sewage sludge. There is a growing
interest in the disposal of sewage sludge in soil; however, the
continuous application of sewage sludge on agricultural lands
may be limited by the accumulation of toxic heavy metals in the
soil. Sewage sludge contains nitrogen (N), phosphorus (P), and
potassium (K), the principal elements needed for plant growth.
The increased cost of chemical fertilizer may make sewage
sludge a valuable fertilizer source once the proper application
rates and cultural practices are established.
Several research findings have shown the effectiveness of
sewage sludge as a fertilizer source. Cunningham et al. (1975)
reported that N, P, and K released from sewage sludge
incorporated into the soil increased the grain yields of corn (Zea
mays L.) and rye (Secale cereale L.). Sabey et al. (1977) noted that
the application of sludge alone or in mixtures with wood wastes
resulted in more wheat (Triticum aestivum L.) growth than did
chemical fertilizer containing high rates of N, P, and K. Day and
Tucker (1977) found that the yield and grain quality of sorghum
(Sorghum bicolor L.) irrigated with sewage effluent were higher
than the yield and quality of sorghum supplied with inorganic
fertilizers containing N, P, and K in amounts equal to those in
sewage effluent. The vegetative growth and grain yields of crops
grown on sludge amended soils were equal to or higher than the
vegetative growth and yield of crops grown with inorganic
fertilizers at conventional rates (Leslie, 1970; Mays et al., 1973).
The major concern in using sewage sludges as fertilizer
sources is their heavy metal content, which could be harmful to
crops and to crop consumers if they are applied in excessive
I Contribution No. 4136 From the Arizona Agricultural
Experiment Station, Tucson, Arizona 85721.
amounts (Ohio Agricultural and Research Development Center,
1975). Johns and Van Laerhoven (1976) stated that the uptake of
heavy metals by plants is influenced more by the nature of the
Day, Thompson, Swingle
Sewage Sludge
105
Table L Average days from planting to flowering, plant height, lodging, grain yield, grain volume -weight, straw yield, and grain /straw ratio for spring wheat
grown with three fertilizer treatments at the Mesa Agricultural Center, Mesa, Arizona (6 -year average).
Fertilizer
treatment
Lodging
Grain
yield
Grain
volumeweight
Straw
yield
Grain/
straw ratio
(cm)
( %)
(kg ha -')
(kg hl-1)
(kg ha -')
(ratio)
106 a
10 b
6,249 a
80 a
9,076 b
0.69 a
79 a
9,683 a
0.66 a
79 a
9,578 a
0.67 a
Planting to
flowering
Plant
height
(day)
151 a+
Suggested N, P, K
from commercial
fertilizer
Sewage sludge to
provide suggested N
with no additional
152 a
fertilizer
110 a
22 a
6,354 a
N, P, K from
commercial
fertilizer equal to
N, P, K in sewage
sludge
153 a
111 a
20 a
6,396 a
+Means, within columns, followed by the same letter are not different at the 5% level of significance.
source material and rate of application of sewage sludge than by
its heavy metal content. Wei et al. (1985) found that the addition
of sewage sludge to clay loam soil decreased bulk density and
increased infiltration rate.
The objectives of the research reported in this paper were to
investigate the effects of dried sewage sludge on the yield and
quality of wheat grain and straw and to study the accumulation
of plant nutrients in soil fertilized with dried sewage sludge for 6
vesting were: (1) days from planting to maturity, (2) plant height,
(3) lodging, (4) grain yield at 120 g kg -' moisture, (5) grain volume- weight, (6) straw yield, and (7) grain /straw ratio.
years.
hay was used as the source of inoculum. Total protein in the
grain and straw was determined by the micro Kjeldahl method
(AOAC, 1955). For heavy metal analysis, the ground samples
were digested with concentrated nitricperchloric acid. Metal
Materials and Methods
An experiment was conducted at the Mesa agricultural Center, Mesa, Arizona, U.S.A. from 1978 through 1983 to compare
the effects of dried sewage sludge and inorganic fertilizers on the
yield and quality of grain and straw from 'Zaragoza' wheat. This
study was conducted in conjunction with a fertilization program
for small grains initiated in 1978 and continued through 1983.
Three fertilizer treatments were used: (1) suggested rates of nitrogen (N), phosphorus (P), and potasium (K) for wheat in Arizona,
(2) dried sewage sludge from the City of Phoenix Sewage Treatment Plant to supply N in amounts equal to the suggested rate,
and (3) inorganic fertilizers to provide N, P, and K in amounts
equal to those applied in the sewage sludge. The suggested fertilizer rate used for wheat was based on past cropping history, soil
tests, and the 1973 University of Arizona recommendations. The
After harvest each year, grain and straw samples were dried
and ground to pass through a 40 -mesh screen. In vitro dry matter
disapearance (IVDMD) was determined using a modification of
the two -stage method developed by Tilley and Terry (1963). Rumen fluid obtained from a fistulated steer maintained on alfalfa
concentrations were then determined by atomic absorption. Lab-
oratory soil analysis to determine soil physical and chemical
changes due to the treatments applied were conducted at the
University of Arizona Soil, Water, and Plant Tissue Testing laboratory before the application of fertilizer treatments in 1978 and
after the termination of the experiment in 1983. Soil pH, electrical conductivity, soluble salts, sodium, and potassium were de-
termined from saturation extract. McGeorge and Breazeale's
method of CO2 extraction was used to evaluate NO3 -N and
PO, -P. Organic matter was analyzed using the method developed by Walkley (1947). All data were analyzed using the stan-
dard analysis of variance and means were compared using the
Student -Newman -Keuls' Test as described by Steele and Tonie
dried sewage sludge contained 16 g kg -' N, 31 g kg -' PZOSi and 3.6
g kg-' K. Based on the analysis, 10 Mg ha -' of dried sewage sludge
(1960).
were applied to supply 160 kg ha-' N (suggested N level). The
three fertilizer treatments were applied during seedbed preparation, prior to planting in December of each year on a Laveen
loam soil. The Laveen series is a member of the coarse -loamy,
mixed hyperthermic Typic Calciorthids. The experimental design was a Randomized Complete Block, with four replications.
The plot size was 52.5 m by 3.6 m (189 m2). The specific treatments for each plot remained unchanged throughout the experimental period, once the treatments were randomized at the beginning of the experiment. In December of each year, the plots
were fertilized, pre -irrigated, and then planted with wheat at the
rate of 112 kg ha-'. The wheat was irrigated as needed to prevent
Results and Discussion
soil moisture stress throughout the growing season. About 76 cm
ha -' of irrigation water were required to produce wheat grain.
The grain was harvested with a combine when the grain was
mature (120 g kg-' moisture). Data obtained before and after har-
Average number of days from planting to maturity, plant
height, lodging, grain yield, grain volume -weight, straw yield,
and grain /straw ratio for wheat grown with the three fertilizer
treatments are presented in Table 1. Wheat grown with sewage
sludge to provide the suggested N with no additional fertilizer
and wheat grown with N, P, and K from commercial fertilizer
equal to the N, P, and K in sewage sludge had higher lodging
percentages and straw yields than did wheat grown with suggested amounts of N, P, and K from commercial fertilizer. These
data indicate that wheat fertilized with sewage sludge produced
more vegetative growth, which resulted in more lodging, than
did wheat grown with conventional treatment. Wheat growers
are interested in a low lodging percentage because a low lodging
Continued on
page 142
Desert Plants 8(3)
142
1987
percentage usually results in less harvest loss and a shorter harvest time. Average number of days from planting to harvest,
plant height, grain yeild, grain volume -weight, and grain /straw
ratio were similar for wheat grown with all fertilizer treatments.
These data suggest that wheat fertilized with sewage sludge poduced grain with the same yield and volume- weight as wheat
fertilized with suggested N, P, and K from commercial fertilizer.
Grain volume -weight is the principal quality factor that determines the price of wheat grain at the grain elevator.
In vitro dry matter disappearance (IVDMD) and total protein
concentrations in wheat grain, which are two important quality
characteristics of livestock feed, were similar in grain from all
fertilizer treatments (Table 2). Wheat grain from all fertilizer
treatments contained relatively low concentrations of cadmium,
zinc, copper, lead, and nickel; however, grain grown with sewage
sludge contained more zinc, lead, and nickel than did grain produced with N, P, and K from commercial fertilizer equal to the
Effects of Sewage
Sludge on Yield and
Quality of Wheat
Grain and Straw in an
Arid Envirônment
(Continued
from page 105)
N, P, and K in sewage sludge or grain produced with suggested N,
P, and K from commercial fertilizer (Table 2). The foregoing data
Table 2. In Vitro Dry Matter Disappearance (IVDMD), protein concentration, and heavy metal concentrations in spring wheat grain in 1983, after 6 years of
three fertilizer treatments at the Mesa agricultural Center, Mesa, Arizona.
Heavy metal concentration
Fertilizer
treatment
IVDMD
Protein
concentration
Cadmium
Zinc
Copper
Lead
Nickel
(g kg-')
(g kg-1)
(mg kg-i)
(mg kg-')
(mg kg-1)
(mg kg-1)
(mg kg -1)
930 a+
138 a
0.0 a
30.1 b
12.4 a
1.3 a
1.3 b
Suggested N, P, K
from commercial
fertilizer
10.4 b
Sewage sludge to
provide suggested N
with no additional
fertilizer
N, P, K from
commercial
fertilizer equal to
N, P, K in sewage
sludge
935 a
145 a
0.0 a
43.1 a
10.0 a
3.3 a
22.0 a
931 a
144 a
0.0 a
33.1 b
10.0 a
1.0 b
14.9 b
+Means, within columns, followed by the same letter are not different at the 5% level of significance.
Table 3. In Vitro Dry Matter Disappearance (IVDMD), protein concentration, and heavy metal concentrations in spring wheat straw in 1983, after 6 years of
three fertilizer treatments at the Mesa Agricultural Center, Mesa, Arizona.
Heavy metal concentration
Fertilizer
treatment
Suggested N, P, K
from commercial
fertilizer
Sewage sludge to
provide suggested N
with no additional
fertilizer
N, P, K from
commercial
fertilizer equal to
N, P, Kin sewage
sludge
IVDMD
Protein
concentration
Cadmium
Zinc
Copper
Lead
Nickel
(g kg-1)
(g kg-1)
(mg kg-1)
(mg kg-1)
(mg kg-1)
(mg kg-1)
(mg kg -')
470 b+
14 b
0.5 a
20.5 a
9.9 a
1.0 b
6.8 b
537 a
38 a
1.4 a
26.1 a
12.5 a
4.1 a
35.7 a
538 a
40a
1.9a
21.8a
12.4a
1.7b
9.9b
+Means, within columns, followed by the same letter are not different at the 5% level of significance.
'
Day, Thompson, Swingle
Sewage Sludge
143
Table 4. Soil analyses before fertilizer treatments in 1978 and after 6 years for three fertilizer treatments in 1983 at the Mesa Agricultural Center, Mesa,
Arizona.
Saturation extract
Fertilizer
treatment
pH
OM
N
P
Electrical
conductivity
Soluble
salts
Na
K
ESP
(g kg-1)
(mg kg-')
(mg kg-1)
(dS m-1)
(mg kg-1)
(mol L-1)
(mol L-')
( %)
Original soil
(1978)
7.8 a
7a
4.3 c
1.9 b
0.4 b
254c
1.7b
0.2b
1.3b
Suggested N, P,
K from
commercial
fertilizer
8.0 a
7a
14.7 b
1.0 b
0.8 a
532 b
3.9 a
0.4 a
3.1 a
7.9 a
6a
29.4 a
5.2 a
1.2 a
833 a
4.9 a
0.5 a
2.7 a
7.9a
6a
27.6a
4.7 a
1.2 a
840 a
5.7 a
0.5 a
3.5 a
(1983)
Sewage sludge to
provide
suggested N
with no
additional
fertilizer
(1983)
N, P, K from
commercial
fertilizer equal
to N, P, K in
sewage sludge
(1983)
+Means, within columns, followed by the same letter are not different at the 5% level of significance.
suggest that a grower can produce high quality wheat grain for
livestock feed using sewage sludge as a source of fertilizer and
that the grain will not contain excessive amounts of cadmium,
zinc, copper, lead, and nickel.
IVDMD and total protein concentrations in wheat straw
grown with sewage sludge alone and straw grown with N, P, and
K from commercial fertilizer equal to the N, P, and K in sewage
sludge were higher than they were in straw from wheat grown
Literature Cited
Association of Official Agriculture Chemists. 1955. Methods of
Analysis. 8th ed. AOAC, Washington, D.C. 1008 pp.
Cunningham, I. D., D. R. Keeney, and J. A. Ryan. 1975. Yield and
metal composition of corn and rye grown on sewage sludge
amended soil. Journal of Environmental quality 4:448 -454.
Day, A. D., and T. C. Tucker. 1977. Effects of treated municipal
wastewater on growth, fiber, protein, and amino acid content
with suggested N, P, and K from commercial fertilizer (Table 3).
These data indicate that wheat can utilize the plant nutrients in
of sorghum grain. Journal of Environmental Quality
sewage sludge as effectively as it can utilize the nutrients in
Johns, M. K. and C. J. Van Laerhoven. 1976. Effect of sewage
sludge composition and lime regime on plant availability of
heavy metals. Journal of Environmental Quality 5:246 -251.
Leslie, R. 1970. Liquid sludges as a farm fertilizer. compost Sci-
commercial fertilizer in the production of high quality straw for
livestock feed in an alkaline soil. This is an important research
observation for both wheat growers and livestock feeders because low -cost wheat straw can be substituted for part of the
high -cost alfalfa hay in cattle feed -lot diets. Wheat straw from all
fertilizer treatments also contained relatively low concentrations
of cadmium, zinc, copper, lead, and nickel; however, straw
grown with sewage sludge contained more lead and nickel than
did straw produced with N, P, and K from commercial fertilizer
equal to the N, P, and K in sewage sludge or straw produced with
suggested N, P, and K from commercial fertilizer (Table 3).
Laboratory analyses showed that the dried sewage sludge used
in this experiment contained 50 mg kg ' Cd, 4000 mg kg -' Zn,
550 mg kg-' Cu, 200 mg kg -' Pb, and 165 mg kg -' Ni. Wheat
plants did not show any toxic effects from any of the fertilizer
treatments. To investigate the effects of heavy metals on wheat,
sewage sludge rates higher than those used in this experiment
may be required. Results from soil analyses conducted in 1978
prior to the initiation of the experiment and in 1983, following
the application of the three fertilizer treatments each year for 6
years, are presented in Table 4. Concentrations of N, P, K, Na,
and total soluble salts were higher in soil fertilized with dried
sewage sludge for 6 years than they were in the original soil
(Table 4). Fertilization with dried sewage sludge for 6 years did
not decrease wheat grain and straw yields or result in any adverse effects on Laveen loam soil that could not be corrected
with minor changes in field crop culture.
6:325 -327.
ence 11:24 -25.
Mays, D. A., G. L. Terman, and J. C. Dugan. 1973. Municipal
compost: Effects on crop yield and soil properties. Journal of
Environmental Quality 2:89 -92.
Ohio Agricultural and Research Development Center. 1975.
Ohio Guide for Land Application of Sewage Sludge. Ohio
Coop. Ext. Ser. Bull. 598.
Sabey, B. R., N. N. Agbin, and D. C. Markstrom. 1977. Land
appication of sewage sludge: IV. Wheat growth, N content, N
fertilizer value,and N use efficiency as influenced by sewage
sludge and wood waste mixtures. Journal of Environmental
Quality 6:52 -58.
Steel, R. G. D., and J. H. Torne. 1960. Principles and Procedures
of Statistics. McGraw -Hill Book Company, Inc. New York.
Tilley, J. M. A., and R. A. Terry. 1963. A two -stage technique for
the in vitro digestion of forage crops. Journal of the British
Grasslands Society 18:104.
Walkley, A. 1947. A critical examination of a rapid method for
determining organic carbon in soils: Effects of variation in
digestion conditions and of inorganic soil constituents. Soil
Science 63:251 -264.
Wie, Q. F., B. Lowery, and A. E. Peterson. 1985. Effects of sludge
application on physical properties of a silty clay loam soil.
Journal of Environmental Quality 14:178 -180.
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