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Advances in agronomy volume 52



Advisory Board
Martin Alexander

Eugene J. Kamprath

Cornell University

North Carolina State University

Kenneth J. Frey

Larry P. Wilding

Iowa State University

Texas A& M University

Prepared in cooperation with the


American Society of Agronomy Monographs Committee
M. A. Tabatabai, Chairman
S. H. Anderson
D. M. Kral
P. S. Baenziger
S. E. Lingle
W. T. Frankenberger, Jr.
R. J. Luxmoore

G. A. Peterson
S. R. Yates


S I N

T

52

Edited by

Donald L. Sparks
Department of Plant and Soil Sciences
University of Delaware
Newark, Delaware

ACADEMIC PRESS
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Copyright 0 1994 by ACADEMIC PRESS, INC.
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Contents
CONTRIBUTORS
........................................................
PREFACE
..............................................................

vii
ix

POULTRY
WASTEMANAGEMENT:
AGRICULTURAL
AND ENVIRONMENTAL
ISSUES
J . T. Sims and D . C. Wolf

I . Poultry Waste Management: Contemporary Issues

................

11. Poultry Wastes: Production and Characteristics ...................
I11. Nitrogen Management for Poultry Wastes ........................

n! Phosphorous Management for Poultry Wastes ....................

2
13
23
35

V. Trace Elements. Antibiotics. Pesticides. and Microorganisms in
Poultry Wastes

..................................................

VI. Poultry Waste Management Programs ............................
V I I. Conclusions .....................................................
References ......................................................

51
59
71
72



RAINWATERUTILIZATION
EFFICIENCY
IN RA~U-FED
LOWLAND RICE
Pradeep Kumar Sharma and Surjit K. De Datta
I. Introduction ....................................................
I1. Constraints .....................................................

I11. Potentials .......................................................

w.

Efficient Utilization of Rainwater ................................
V. Research Priorities ..............................................
VI. Summary .......................................................
References ......................................................

85
87
91
92
112
112
113

WETLANDSOILSOF THEPRAIRIE
POTHOLES

J . L . Richardson. James L . Arndt. and John Freeland
I. Introduction ....................................................
I1. Climate. Basic Hydrologic Concepts. and Wetland Classification . .
111. Geologic Factors ................................................
rv. Water Quality ..................................................
V

121
124
138
141


vi

CONTENTS

V. Wetland Soil Properties .........................................
VI. Soil Sequences ..................................................
VII. Soils on Prairie Pothole Edges ...................................
VIII. Conclusions and Future Work ...................................
References ......................................................

148
1SO
161
163
165

NEWDEVELOPMENTS
AND PERSPECTIVES
ON SOIL POTASSIUM QUANTITY/~NTENSITY
RELATIONSHIPS

V. P. Evangelou. Jian Wang. and Ronald E . Phillips
I. Introduction ....................................................
I1. Electrochemical Considerations ..................................
111. Quantityhtensity ..............................................

IV. Basis of Molecular Interpretation of QuantityAntensity ...........
V. Rapid Approaches for Quantity/Intensity Determinations .........
VI. Experimental Observations and Future
Quantity/Intensity Applications ..................................
References ......................................................

173
176
181
189
209

215
220

MORPHOLOGICAL
AND PHYSIOLOGICAL
TRAITS
ASSOCIATED WITH WHEAT YIELD INCREASES

INMEDITERRANEAN
ENVIRONMENTS
Stephen P. Loss and K. H. M . Siddique
I . Introduction ....................................................
I1. Constraints in Mediterranean Environments ......................
111. Biomass Production and Partitioning .............................
IV. Water Use ......................................................
V. Radiation Use ...................................................
VI . High-Temperature Stress ........................................
VII . Use for Breeders ................................................
VIII . Concluding Comments ..........................................
References ......................................................

229
232
236
251
258
261
262
265
266

INDEX.................................................................

277


a
Numbers in parentheses indicate the pages on which the authors’ contributions begin.

JAMES L. ARNDT (12 I), Department of Soil Science, North Dakota State University, Fargo, North Dakota 581OS
SURJIT K. DE DATTA (as), Office oflnternational Research and Development,
Virginia Polytechnic Institute and State University, Blacksburg, Virginia 24061,
and International Rice Research Institute, Manila, Philippines
V. P. EVANGELOU (17 3 ) , Department of Agronomy, University o f Kentucky,
Lexington, Kentucky 40546
JOHN FREELAND (12 l), Department of Soil Science, North Dakota State
University, Fargo, North Dakota 58105
STEPHEN P. LOSS (229), Division of Plant Industries, Department of Agriculture, Western Australia, South Perth, Western Australia 6151, Australia
RONALD E. PHILLIPS (17 3 ) , Department of Agronomy, University of Kentucky, Lexington, Kentucky 40546
J. L. RICHARDSON (121), Department of Soil Science, North Dakota State
University, Fargo, North Dakota 58105
PRADEEP KUMAR SHARMA (as), Ubon Rice Research Center, Ubon Ratchathani 34000, Thailand, and International Rice Research Institute, Manila,
Philippines
K. H. M. SIDDIQUE (229), Division of Plant Industries, Department ofAgriculture, Western Australia, South Perth, Western Australia 6151, Australia
J. T. SIMS (l), Department of Plant and Soil Sciences, University of Delaware,
Newark, Delaware 19717
JIAN WANG (17 3 ) , Department of Agronomy, University of Kentucky, Lexington, Kentucky 40546
D. C. WOLF (l), Department OfAgronomy, University ofArkansas, Fayetteville,
Arkansas 72701


This Page Intentionally Left Blank


Preface
Volume 52 includes a number of advances in the crop and soil sciences that
should be of great interest to the readership. The first chapter is a comprehensive
review of agricultural and environmental issues associated with poultry manure
management, including discussions on production and characteristics of poultry
wastes, nitrogen and phosphorous management of poultry wastes, trace elements, antibiotics, pesticides, and microorganisms in poultry waste, and poultry
waste management programs. The second chapter discusses aspects of rainwater
utilization efficiency in rain-fed lowland rice, including constraints, potentials,
efficient utilization, and research priorities. The third chapter discusses wetland
soils of the prairie potholes. Topics that are covered include climate, basic hydrologic concepts and wetland classification, geologic factors, water quality,
wetland soil properties, soil sequences, and soils on the prairie pothole edges.
The fourth chapter is a comprehensive review of the advances in soil quantity/
intensity ( Q / I )relationships, an index that has been widely employed over the
years to assess nutrient availability in soils. Discussions on electrochemical considerations, quantitylintensity interpretations and applications, and rapid techniques for making Q/I measurements are included. The fifth chapter deals with
morphological and physiological traits associated with wheat yield increases in
Mediterranean environments and discusses constraints in these environments,
biomass production and partitioning, water and radiation use, high-temperature
stress, and use for plant breeders.
I appreciate the fine contributions of the authors.
DONALD
L. SPARKS

ix


This Page Intentionally Left Blank


POULTRY
WASTEMANAGEMENT:
AGRICULTURAL
AND ENVIRONMENTAL
ISSUES
J, T. Simsl and D. C. Wolf*
'Department of Plant and Soil Sciences
University of Delaware
Newark, Delaware 19717
ZDepartment of Agronomy
University of Arkansas
Fayetteville, Arkansas 72701

I. Poultry Waste Management: Contemporary Issues
A. Water Quality and Nutrient Management
B. Pesticides, Antibiotics, and Heavy Metals in Poultry Wastes
C. Dead Poultry Disposal
11. Poultry Wastes: Production and Characteristics
A. Poultry Production Operations and Types of Waste
B. Properties and Composition of Poultry Wastes
C. Appropriate Use of Poultry Waste Analyses
111. Nitrogen Management for Poultry Wastes
A. Forms in Poultry Wastes
B. Nitrogen Transformations in Storage and Handling
C. Nitrogen Losses Due to Drying Poultry Wastes
D. Nitrogen Transformations in Soils
E. Crop Response to Nitrogen in Poultry Wastes
IV Phosphorous Management for Poultry Wastes
A. Phosphorous Concentration and Form in Soils Amended
with Poultry Wastes
B. Phosphorous Retention and Movement in Soils Amended
with Poultry Wastes
V. Trace Elements, Antibiotics, Pesticides, and Microorganisms
in Poultry Wastes
A. Trace Elements
B. Antibiotics, Coccidiostats, and Pesticides in Poultry Wastes
C. Microbial Population of Poultry Wastes
VI. Poultry Waste Management Programs
A. Overview of Agricultural Management Plans for Poultry Wastes
B. Nutrient Management Plans
VII. Conclusions
References
1

Advances in Agrnnmy, W u m e 12
Copyright Q 1994 by Academic Press, Inc. All rights of reproduction in any form reserved.


2

J. T. SLMS AND D. C. WOLF

I. POULTRY WASTE MANAGEMENT:
CONTEMPORARY ISSUES
The poultry industry is one of the largest and fastest growing livestock production systems in the world. Globally, almost 40 million metric tons of poultry
meat and 600 billion eggs were produced in 1991 (Foreign Agricultural Service,
1992). The dominant producers of poultry meat and eggs are the United States,
China, the former Soviet Union countries, Brazil, France, and Japan (Table I).
On a worldwide basis, poultry meat and egg production is growing at an annual
rate of approximately 5%. The economic impact of the poultry industry to global
and national economies is significant and of increasing importance. For example,
in 1991 the United States produced 6.1 billion broiler chickens, 285 million
turkeys, and 68 billion eggs, with a total production value of $14.7 billion (Economic Research Service, 1992). In comparison, the total dollar value of poultry
production in the United States in 1980 was $9 billion (National Agricultural
Statistics Service, 1992). Much of the U.S. poultry production is for export
purposes. In 1991 the United States exported approximately 623,000 metric tons
of broiler and turkey meat and nearly 2 billion eggs. Major importers of U.S.
poultry products were China (Hong Kong), Japan, Mexico, and Canada (Economic Research Service, 1992). The localized nature of poultry production also
means that it can represent a large percentage of the agricultural economy in
many states or regions. In Delaware, for example, the poultry industry accounts
for nearly 70% of the total agricultural income in the state, with the value of
processed and delivered broilers in 1991 equivalent to $1.2 billion (Delaware
Department of Agriculture, 1992).
Although economically successful, the poultry industry is currently faced with
a number of highly complex and challenging environmental problems, many of
which are related to its size and geographically concentrated nature. The development of management programs that meet the increasing demand for poultry
products, while minimizing the environmental effects of poultry wastes on soils,
crops, surface waters, and groundwaters, will be the focus of this article. Other
environmentally related issues, such as air quality and odor control, disposal of
dead or diseased poultry, food safety, and animal health and welfare, also confront the poultry industry. However, from an agricultural perspective, the role of
poultry wastes in the contamination of groundwaters by nitrate nitrogen (NO,-N),
the eutrophication of surface waters by nitrogen and phosphorus, and the fate of
pesticides, heavy metals, and pathogens applied to soils in poultry wastes are the
central environmental issues at the present time.
This article will provide a brief overview of each of these issues, a description
of the types and compositions of poultry wastes, and a review of recent research
addressing the agricultural and environmental aspects of poultry waste manage-


3

POULTRY WASTE MANAGEMENT
Table I
Global Production of Poultry Meat and Eggs and Recent Growth in the Poultry Industry
Poultry meat
production (lo00 Mg
RTC" equivalents)
Country

North America
Canada
Mexico
United States
South America
Argentina
Brazil
Venezuela
Europe
France
Germany
Italy
The Netherlands
Spain
United Kingdom
Eastern Europe
Hungary
Poland
Romania
Former Soviet Union
(includes 12 countries)
Africa and Middle East
Egypt
South Africa
Saudi Arabia
Turkey
Asia and Oceania
Australia
China
Japan
South Korea
Taiwan
All other countries
Total

Egg production
(million pieces)

1988

1993b

1988

1993

656
592
9272

727
1040
12,157

5721
17,859
69,410

5630
21,110
70,200

370
1997
373

520
3195
34 1

3300
14,850
2700

4730
14,750
2400

1434
576
996
485
829
1056

1870
640
1056
565
864
1260

15,300
17,960
I 1,234
10,761
10,856
11,736

15,700
15,600
1 1.570
10,800
10,400
1 1,420

465
35 1
370
3107

350
350
3 10
2527

4695
8220
7650
82,204

4100
7500
7200
65,250

279
545
248
236

225
560
290
335

2840
3723
2765
6200

3000
4355
3040
8100

40 1
2744
1471
235
418
3187
32,693

455
5200
1370
350
510
3856
40,923

3238
139,100
40,137
7204
4400
34,129
538,192

3784
20,500
43 ,Ooo
8500
4800
33,177
595.1 16

"RTC, Ready to cook.
1993 values as forecast by USDA Foreign Agricultural Service.


4

J. T. SIMS AND D. C. WOLF

ment. We will conclude by describing current best management practices for the
use of poultry wastes in agriculture and by offering alternative approaches that
may reduce the environmental impacts of poultry wastes.

A. WATERQUALITY
AND NUTRIENT
MANAGEMENT
Poultry wastes contain all essential plant nutrients (C, N, P, K, S , Ca, Mg, B,
Cu, Fe, Mn, Mo, and Zn) and have been well-documented to be excellent fertilizers (Bouldin e? al., 1984; Edwards and Daniel, 1992; Hileman, 1967b; Pennsylvania State College, 1944; Perkins et al., 1964; Simpson, 1990; Sims, 1987;
Sommers and Sutton, 1980; Stephenson et al., 1990; Wilkinson, 1979). However, improper management of poultry wastes has been shown to contribute to
NO,-N pollution of groundwaters and eutrophication of surface waters (Edwards
and Daniel, 1992; Liebhardt et al., 1979; Magette et al., 1989; Ritter and Chirnside, 1987; Weil ef al., 1990).
Groundwater contamination by N03-N is an issue of global concern; the
causes and related environmental effects of NO,-N pollution have been discussed
in a number of comprehensive review articles [Greenwood, 1990; Keeney, 1982;
Strebel et al., 1989; U.S. Department of Agriculture (USDA), 19911. In brief,
the basis for much of this concern is the potential effects of NO,-N on the health
of human infants and animals. Infants younger than 3 months of age that consume water contaminated with NO,-N are susceptible to methemoglobinemia,
also referred to as “blue-baby syndrome.” Methemoglobinemia is not caused
directly by NO; but occurs when NO; is reduced to nitrite (NO:) by bacteria
found in the digestive tract of human infants and animals. Nitrite can then oxidize the iron in the hemoglobin molecule from Fez to Fe3+,forming methemoglobin, which cannot perform the essential oxygen transport functions of hemoglobin. This can result in a bluish coloration of the skin in infants, hence the
origin of the term blue-baby syndrome. Methemoglobinemia is a much more
serious problem for very young infants than for adults, because after the age of
3-6 months the acidity in the human stomach increases to a level adequate to
suppress the activity of the bacteria that reduce NOT to N O ? . Although documented cases of methemoglobinemia are extremely rare, the U. S . Environmental
Protection Agency has established a maximum contaminant level of 10 mg N03-N/
liter (45 mg NOJliter) to protect the safety of U.S. drinking water supplies [U.S.
Environmental Protection Agency (USEPA), 19851. The European Economic
Community (EEC) (1980) has established a similar standard of 1 1 mg N03-N/
liter (50 mg NOJliter). Animals can also be susceptible to methemoglobinemia,
although the health advisory level for most livestock is much higher, approximately 40 mg NO,-N/liter (180 mg NOJiter).
Eutrophication is defined as an increase in the nutrient status of natural waters
+


POULTRY WASTE MANAGEMENT

5

that causes accelerated growth of algae or water plants, depletion of dissolved
oxygen, increased turbidity, and a general degradation of water quality. The enrichment of lakes, ponds, bays, and estuaries by N and P from surface runoff or
groundwater discharge is known to be a contributing factor to eutrophication.
The levels of N required to induce eutrophication in fresh and estuarine waters
are much lower than the values associated with drinking water contamination.
Although estimates vary, and depend considerably on the N:P ratio in the water,
concentrations of 0.5 to 1.O mg N/liter are commonly used as threshold values
for eutrophication. Marine or estuarine environments, where salinity levels are
greater, are more sensitive to eutrophication and thus have lower threshold levels
of N (c0.6 mg N/liter) (USDA, 1991). The eutrophication threshold for most
P-limited aquatic systems is even lower, ranging from 10 to 100 p g P/liter
(Mason, 1991). Water bodies with naturally low P concentrations will, therefore,
be highly sensitive to external inputs of P. Once eutrophic conditions are established, algal blooms and other ecologically damaging effects can occur, including low dissolved oxygen levels, excessive aquatic weed growth, increased sedimentation, and greater turbidity. Decreased oxygenation is the primary negative
effect of eutrophication because low dissolved oxygen levels seriously limit the
growth and diversity of aquatic biota and, under extreme conditions, cause fish
kills. The increased biomass resulting from eutrophication causes the depletion
of oxygen, especially during the microbial decomposition of plant and algal residues. Under the more turbid conditions common to eutrophic lakes, light penetration into lower depths of the water body is decreased, resulting in reduced
growth of subsurface plants and benthic (bottom-living) organisms. In addition
to ecological damage, eutrophication can increase the economic costs of maintaining surface waters for recreational and navigational purposes. Algal surface
scums, foul odors, insect problems, impeded water flow and boating due to
aquatic weeds, shallower lakes that must be dredged to remove sediment, and
disappearance of desirable fish communities are among the most commonly reported undesirable effects of eutrophication.
Strebel et al. (1989) cited three main causes of NO,-N pollution of groundwaters in Europe: (1) intensified plant production and increased use of N fertilizers, (2) intensified livestock production with high livestock densities that cause
enormous production of animal wastes on an inadequate agricultural land base,
and (3) conversion of large areas of permanent grassland to arable land. Eutrophication of surface waters by N and P reflects both the contribution of agricultural inputs that are primarily nonpoint in nature, such as soil erosion and
runoff, and inputs from direct discharge of wastewaters from municipalities, industry, urban stormwater systems, and recreational developments (Mason, 1991 ).
Atmospheric deposition of N, as both precipitation (“acid rain,” primarily as
nitric acid, HNO,) and particulate matter, and fixation of atmospheric N by
aquatic organisms also contribute to the total pool of N in surface waters. Am-


6

J. T. SIMS AND D. C. WOLF

monia gas that has volatilized from areas of concentrated animal production may
also be deposited by precipitation in nearby surface waters.
Groundwater and surface water contamination by N and P in poultry wastes is
primarily an issue of nonpoint source pollution. The manures, litters, sludges,
composts, and wastewaters originating from poultry production operations are normally used in large-scale land application programs and are rarely concentrated
enough to be considered a point source of N or P. Some exceptions exist, such as
manure storage areas, the direct discharge of wastewaters from poultry processing plants into streams or rivers, and the disposal of large quantities of dead poultry in landfills due to a major disease outbreak. Situations such as these are
subject to regulation and long-term monitoring by environmental protection agencies and will not be discussed in this article. We will focus on nonpoint source
pollution caused by poultry wastes used for the production of agricultural crops.
The causes and management of N and P pollution from poultry wastes can be
viewed at essentially three scales: field, farm, and regional. At the smallest scale,
such as an agricultural field where poultry manure is used as a fertilizer, the
overapplication or poorly timed application of manure can result in excess nutrients in the soil and/or enhanced losses of nutrients by physical processes such
as leaching, erosion, runoff, or volatilization. At the farm scale, wherein literally
hundreds of thousands of animal units can be produced annually on only a few
hectares of land, the environmental issue is the availability of adequate cropland
to use the nutrients generated in the production and processing operations. A
similar scenario exists at a state or regional perspective; however, at this level
management of poultry wastes must be integrated into a broader nutrient management program that considers all sources of nutrients, including commercial
fertilizers, legumes, and municipal sludges, composts, and wastewaters.
It is imperative to keep the issue of scale in mind when addressing nutrient
management of poultry wastes. Management programs that identify proper application rates and techniques for individual fields are of little value if a farm or
region has an enormous surplus of waste. Larger scale solutions must be developed that address surpluses at the farm and regional level. Poultry production is
often highly localized within a state or region. In the United States, 90% of the
6.1 billion broiler chickens produced in 1991 were grown in 15 states; 55% of
the eggs were produced in eight states (National Agricultural Statistics Service,
1992). This localization has often been due to favorable transportation, marketing, or climatic conditions. Unfortunately, many areas in the United States where
the poultry industry is concentrated are unfavorable from the point of view of
effective use of the wastes generated by the industry. Two examples of the nature
of environmental problems that can arise when the poultry industry is concentrated in relatively small geographic area are the Delmarva (Delaware-Maryland-Virginia) peninsula and northwestern Arkansas.


POULTRY WASTE M ~ A ~ E M E N T

7

1. Nutrient Management and Water Quality:
The Delmarva Peninsula
In 1991 over 537 million broiler chickens were produced on the Defmarva
~ n i n s u l a an
, area with about 800,000 ha of cropland (W. Satterfield, Delmarva
Poultry Industry, Inc., personal communication). More than 220 million broilers
were produced in Sussex County, Delaware, alone, generating an estimated
270,000 Mg of manure (wet weight basis). The annual economic value of the
nutrients in this manure, using current estimates (Stephenson et a f . , 1990),
would be approximately $8 to $10 million. Virtually all of this manure is used
in land application programs for the approximately 120,000 ha of grain crops
and vegetables grown in the county. Approximately 50% of the cropland is used
for soybeans (Gtycine mux L.), which require no fertilizer or manure N. Current
manure recommendations for corn (Zea mays L.), wheat ( ~ r j ~ jaes~ivum
c u ~ L.),
barley (Hordeurn vulgaris), and vegetables typically range from 4 to 8 Mg/ha
(no manure is recommended for soybeans). Based on these estimates, the manure
generated by the poultry industry could supply essentially all nutrients needed
by all crops, if it were evenly distributed throughout this county. Unfortunately,
the unfavorable economics of manure tr~sportationcurrently prevent movement
of manure more than a few kilometers. Further complicating the nutrient management issue is the fact that fertilizer consumption (sales) in Delaware averaged
175 kg N/ha (soybeans excluded) and 16 kg P/ha (a11 crops) (Delaware Department of Agriculture, 1992). Beyond this, the rapidly urbanizing nature of Deiaware and many other northeastern states may mean that more cropland will be
needed for land application of the municipal wastes and wastewaters generated,
and thus less cropland will be available for poultry waste application. Finally,
although location of the poultry industry on the Delmarva peninsula makes economic sense, because of the ready access to literally tens of millions of consumers in the eastern United States, from a water quality perspective the geographic
location presents major problems. The peninsula is dominated by coarse, welldrained soils that overlie shallow water tables (often less than 5 m), in a temperate area with plentiful rainfull (- 125 cm/year). Groundwaters discharge into
highly sensitive and important surface waters, including the Chesapeake Bay, the
Delaware Bay, and Delaware’s Inland Bays (a national estuary). The relatively
flat topography of the peninsula reduces erosion and runoff, but enhances infiltration and groundwater recharge. Groundwater NO,-N concentrations in many
areas of this peninsula commonly exceed the 10 mg Nlfiter drinking water standard established by the U.S. EPA (Hamilton and Shedlock, 1992). Ritter and
Chirnside (1987) surveyed more than 200 wells in southern Delaware, 70% of
which were from individual homes. They reported that more than 34% of the
wells tested in Sussex County had NO,-N concentrations in excess of 10 mg


J. T. SIMS AND D. C. WOLF

N/liter and cited intensive agricultural activity, particularly land application of
poultry manure, as the cause.
Concentration of the poultry industry in an area without adequate cropland
can also result in the accumulation of soil P to excessive levels. Most land management programs for poultry wastes are based on N management to reduce the
likelihood of groundwater contamination by NO,-N. The N : P ratio of poultry
wastes, however, usually results in the addition of P beyond crop removal in
harvested biomass, except in extremely P-deficient soils. For example, application of poultry manure at the rate normally recommended to meet the N requirements of corn (5 Mg/ha, dry weight basis), at yield goals typical to the Delmarva
peninsula (7 Mg/ha), adds about 135 kg P/ha to the soil, relative to P removal
of approximately 25 kg P/ha in harvested corn grain. The net effect of N-based
manure management, therefore, is ever-increasing soil P levels. Recent soil test
information summaries from the state of Delaware confirm this P buildup in
manured soils. Soil test summaries from 1991 to 1992 for Sussex County, Delaware showed that 77% of soil samples from agricultural fields had high or exces0.025 N H,SO,); 28% had
sive levels of soil test P (Mehlich 1, 0.05 N HCI
soil test P values in excess of 140 mg P/kg, twice the level at which no fertilizer
P would be recommended (K. L. Schilke-Gartley, University of Delaware, personal communication). Mozaffari and Sims (1994) measured soil test P in the
surface horizons (0-20 cm) of 48 cultivated fields from Sussex County with a
history of frequent manure use. The median value for soil test P was 128 mg
P/kg; 9 of the 48 soils were rated as high in P (>35 mg P/kg) and 35 as excessive
in P (>70 mg P/kg). Other surveys of soil test P in areas dominated by animalbased agriculture have shown similar trends. Baker (1986) sampled 70 agricultural fields in Lancaster County, Pennsylvania and found that the soil test P (Bray
P1, 0.03 N NH,F
0.025 N HCI) levels averaged 131 mg P/kg (range = 36
to 41 1 mg P/kg), relative to a desired value of 50 mg P/kg.
The fate and environmental impacts of P from poultry wastes are discussed in
more detail in Section IV. Clearly, however, in areas where surface waters are
sensitive to eutrophication, effective P management of poultry wastes is critical.
This management must include an understanding not only of how manure P
reacts with soils, but of the processes that can transport P from waste-amended
soils to surface waters, such as erosion, runoff, artificial drainage, and, in certain
excessively well-drained soils, leaching and groundwater discharge.

+

+

2. Nutrient Management and Water Quality: Arkansas
In 1991, Arkansas ranked first in the United States in poultry production with
over 980 million broilers, fourth in turkey production with 24 million turkeys,
and sixth in egg production with 3.7 billion eggs (Arkansas Agricultural Statis-


9

POULTRY WASTE MANAGEMENT
Table I1
Number of Poultry and Quantity of Poultry Waste Produced in Arkansas and Delaware
during 1991

Source

Arkansas
Broilers
Turkeys
Laying hens
Delaware
Broilers
Laying hens

Waste
Total
Produced waste
Number per bird produced
(millions) (dry kg) (dry Gg)

Typical level (%)

Total produced (Gg)

N

P

K

N

P

K

36
12
6

13
8
1

19
14
4

980
24
16

0.9
18.6
12.7

882
446
203

4.1
2.8
3.0

1.5
1.7
3.3

2.2
3.2
2.2

220
0.7

0.9
12.7

198
9

4.1
3.0

1.5
3.3

2.2
2.2

8
0.3

3
0.3

4
0.2

tics Service, 1992). The value of commercial broiler, turkey, and egg production
was approximately $1.37 billion, $186 million, and $286 million, respectively.
The total farm value of poultry and eggs produced in 1991 in Arkansas was
$1,851,925,000 (National Agricultural Statistics Service, 1992).
In addition to the meat and eggs produced, the poultry industry in Arkansas,
as in Delaware, generated substantial quantities of poultry waste (Table 11). Estimates for the amount of nutrients contained in the poultry waste would suggest
that the value of waste material as fertilizer would be $28 million to $40 million
in 1991 (J. T. Gilmour, unpublished data). Stephenson et al. (1990) and Smith and
Wheeler (1979) have calculated the fertilizer value of broiler litter as $31.23/Mg
and $32.67/Mg, respectively.
The majority of the poultry waste is recycled as an organic amendment on
pastureland in western Arkansas. In fact, the increase in broiler production in
Arkansas has been paralleled by an increase in beef production largely due to the
availability of an economical source of fertilizer in the form of poultry waste.
Broiler litter has been used extensively on tall fescue (Festuca arundinacea
Schreb.) and bermuda grass [Cynodon dactylon (L.) Pers.] pastures.
The annual maximum broiler litter application rate for cool-season grasses
recommended by the University of Arkansas Cooperative Extension Service is
9 Mg/ha, with no more than 5.6 Mg/ha in a single application. The USDA Soil
Conservation Service recommendation is 6.7 Mg/ha per year with no more than
3.4 Mg/ha in a single application. Both recommendations are based on providing
adequate N fertility for forage production, as is common in most state animal
waste application programs (Wallingford el al., 1975). Arkansas, Delaware, and
most other states do not currently consider P or heavy metals as limiting factors


10

J. T. SIMS AND D. C. WOLF

in land application of poultry waste. However, excessive P levels are increasingly being recognized as a limitation for poultry waste application to soils (see
Section IV).
Because the soils in the Ozark region tend to be shallow and are often over
limestone aquifers that are used as sources of drinking water, increasing concern
has been expressed regarding the role of poultry litter in NO3-N and fecal coliform contamination of groundwater (Daniel et al., 1992; Wolf, 1992; Wolf and
Daniel, 1989). Edwards and Daniel (1992) recently presented an excellent review of the environmental impact of on-farm poultry waste disposal.
Steele and McCalister (1991) reported that well water from a poultryproducing area averaged 2.83 mg NO,-N/liter compared to 1.73 mg NO,-N/liter
for a forested control area in the Ozark region of northwestern Arkansas. The
NO,-N levels in springs were also evaluated and ranged from 2.58 to 3.23 mg/
liter in the poultry-producing area, compared to 0.02 to 0.40 mglliter in the
control area (Adamski and Steele, 1988). Scott et al. (1992) reported data from
the sampling of 63 wells and 18 springs in a poultry-producing area of northwestern Arkansas and reported median NO,-N concentrations of 0.4 and 3.2 mg/
liter, respectively. However, 20 of the wells and 10 of the springs had median
NO3-N levels of 5.6 and 5.9 mg/liter, respectively. These findings suggest that
application of poultry litter to pasture land had adversely impacted groundwater
quality as shown by NO,-N concentrations above the 3 mg/liter level in wells
and springs. However, preliminary results from a recent survey of domestic well
water samples in northwestern Arkansas suggest that less than 5% of the samples
collected exceeded the 10 mg N/liter maximum concentration limit set by the
U.S. Environmental Protection Agency (S. L. Chapman, personal communication, 1992).
In addition to NO,-N contamination of groundwater, surface runoff can contaminate lakes and streams with P and result in eutrophication. Because land
application rates for poultry waste are generally derived from plant requirements
for N, excessive levels of P can be applied to and accumulate in the soil. The
1989 summary of soil test results for over 2000 soil samples collected from
pastures in selected Arkansas counties showed that the addition of manure had
resulted in large increases in available P and modest increases in extractable K
in soils with a history of manure application (J. T. Gilmour, unpublished data).
This summary showed soil test P (Mehlich 3, 0.2 N CH,COOH + 0.025 N
NH,NO, + 0.015 N NH,F
0.013 N HNO, + 0.001 M EDTA) increased
from a weighted mean of 59 mg P/kg for soils that had not been amended with
manure to 106 mg P/kg in soils amended with manure. Fertilizer P is not recommended for forage production when soil test levels are >50 mg P/kg. Extractable K was also increased by manure addition from 142 mg K/kg in nonamended
soils to 168 mg K/kg in soils amended with manure. No fertilizer K is recommended when soil test levels are >150 mg K/kg. Because P addition to lakes

+


POULTRY WASTE MANAGEMENT

I1

and streams can often be the critical nutrient to initiate the eutrophication process, concern regarding high P levels in manure-amended soils continues to grow
(Decker, 1992). Erosion of surface soil with high P concentrations can represent
a potentially serious environmental problem as does direct transport of soluble P
or surface-applied poultry waste into water systems.
Contamination of groundwater and surface water with pathogenic microorganisms is also an important environmental concern. Fecal coliform and Escherichia coli are generally used as indicators of pathogens in water sources. Runoff
from areas where poultry waste has been applied can contaminate surface water
with fecal microorganisms. In northwestern Arkansas, fecal coliform levels often
exceed the 200 fecal coliforms/100 ml limit established for primary contact
water, and poultry waste applied to pasture land may often be the primary source
of fecal coliforms (Arkansas Department of Pollution Control and Ecology,
1992).
Because nutrient and bacterial contamination of groundwater and surface
water has had such an important impact on drinking and recreational water
sources in Arkansas, there is little doubt that greater attention will be focused on
management practices to protect water quality and recycle nutrients in poultry
waste in the poultry-forage-beef production systems that dominate production
agriculture in the state.

B. PESTICIDES,
ANTIBIOTICS,
AND HEAVY
METALS
INPOULTRY
WASTES
Nutrients are not the only constituents of poultry wastes that can have an
environmental impact. Pesticides used to control insects in poultry houses and
heavy metals, antibiotics, and coccidiostats used as feed additives for nutritional
or disease-related purposes are also of concern. Limited research, however, has
been conducted on the fate of these waste constituents following their application
to agricultural soils.
Pesticide degradation and mobility in soils are issues of great national interest.
Most studies have evaluated the fate of pesticides directly applied to soils for the
control of weeds, insects, or pathogens. One example of a pesticide used in
poultry production is cyromazine, an s-triazine larvacide that is mixed with poultry feed and passed through the animal to control fly populations in broiler
houses. Recent preliminary research has shown that heavy manure applications
and intensive rainfall can cause cyromazine losses in runoff (Pote et al., 1994).
Antibiotics and coccidiostats include compounds such as amprolium, salinomycin, streptomycin, tetracycline, and terramycin. Very little research has been
conducted on the environmental fate of any of these chemicals after manure or
litter containing them is applied to the soil.


12

J. T. SIMS AND D. C. WOLF

Heavy metals are often the land-limiting constituent in organic waste management programs for municipalities and industries. As an example, in Delaware,
the length of time an agricultural field can receive municipal sewage sludge is
ultimately based on total heavy metal inputs. Lifetime site loading rates currently
used for Cd, Cu, Ni, Pb, and Zn applied to a soil with a cation exchange capacity
between 0 and 5 cmol/kg are 5, 140, 140, 560, and 280 kg/ha. Heavy metal
concentrations in poultry wastes can be similar to or even exceed those reported
for domestic sewage treatment plants. Metals are normally added to the poultry
diet as salts, such as CuSO,, NaSeO,, or as acids, such as 3-nitro-4-hydroxyphenylarsonic acid; they may also occur naturally in the grains used in the diet.
The median values for As, Cd, Cr, Cu, Ni, Pb, and Zn reported for sewage
sludge in the northeastern United States were 10, 15, 500, 800, 80, 500, and
1700 mg/kg, respectively (Baker, 1985). Malone et al. (1992) collected broiler
litter samples from 60 poultry farms in Delaware and found that Cu and Zn
values ranged from 289 to 920 and 315 to 680 mg/kg. Analyses of 275 manure
samples submitted by farmers to the University of Maryland from 1985 to 1989
had average values of 168 and 223 mg/kg for Cu and Zn; maximum values were
527 and 620 mg/kg, respectively (Bandel, 1988). Kunkle et al. (1981) reported
average As, Cd, Cu, Hg, Pb, and Se values after five flocks of broiler chickens
were 35, 0.5, 319, 0.3, 3, and 0.3 mg/kg. The addition of heavy metals in
poultry wastes to soils is not regulated at the present time, despite the similarity
in heavy metal concentrations noted with wastes that are regulated. This suggests
that research on,the fate of metals in soils amended with poultry wastes may be
needed to determine if guidelines or regulations similar to those mandated for
municipal and industrial wastes are necessary for poultry wastes.

C. DEADPOULTRY
DISPOSAL
Animal mortality, a common problem in the poultry industry, can result in
significant waste disposal problems for farmers; these problems can be enormously greater if a major disease outbreak occurs. In 1991 more than 36 million
chickens, excluding broilers, were lost due to mortality (National Agricultural
Statistics Service, 1992). The number of broilers lost is more difficult to estimate
given the large number of individual farmers involved in broiler production.
However, based on the normal mortality estimates of 2-3% commonly used for
broilers by the poultry industry, over 120 million broilers die and must be disposed of each year. Until recently, on-farm disposal has normally involved burying the dead poultry in large pits, with little if any consideration given to the
potential for groundwater pollution as the carcasses decompose. Recent advances
in composting and farm-based acid-rendering tanks have provided some alternatives for normal mortality, but are still inadequate to handle catastrophic losses
involving tens of thousands of birds. Further, the possible transmission of dis-


POULTRY WASTE MANAGEMENT

13

h

m
.-

fcn

400

'

+ Poultry Compost

Y

Y

aJ

Y

2
n

300

Figure 1 Effect of composting raw poultry manure on the rate and extent of N mineralization
in an Evesboro loamy sand soil, relative to the typical pattern of N uptake by corn (Sims er a [ . ,
1993).

ease organisms during the handling and land application of dead poultry composts is a major concern to the poultry industry. Initial research has shown that
two-stage composting can destroy many pathogenic organisms, but the fear of
increasing poultry mortality by the distribution of inadequately composted poultry wastes remains.
Composting dead poultry with a carbon source (e.g., straw) and with poultry
manure has been shown to decompose poultry carcasses successfully (Murphy
and Handwerker, 1988; Palmer and Scarborough, 1989; Sims et al., 1993). The
dead poultry compost, as with other composted wastes, is a stable material that
releases N more slowly than does raw manure or broiler litter (mixture of poultry
excreta and woodchips or sawdust). Composting of dead birds has the potential,
therefore, to improve the agronomic and environmental efficiency of land application programs using poultry wastes by improving the synchrony of N release
with crop N uptake (Fig. 1).

11. POULTRY WASTES: PRODUCTION
AND CHARACTERISTICS
As with all industries, there are many different types of waste materials generated during the production of poultry and eggs. Effective environmental man-


14

J. T. SIMS AND D. C. WOLF

agement of any poultry waste begins with an understanding of its composition
and the physical, chemical, and microbiological reactions that control the fate of
potential pollutants in the waste following land application. Simpson (1990) recently reviewed the topic of agricultural use of poultry wastes and identified the
three most common poultry wastes as (1) poultry manure (urine and feces) or
poultry litter (a mixture of manure and the woodchips used as a base in broiler
houses), (2) dissolved air flotation (DAF) sludge originating from poultry processing plants, and (3) composts produced from hatchery wastes and dead birds.
Wastewaters from poultry processing plants are also commonly applied to agricultural lands, but these operations are relatively small in magnitude relative to
programs that involve land application of manures, litters, sludges, and composts. Wastewater irrigation also normally requires strict adherence to regulations established by state environmental agencies. Limited information is available on the nature and use of wastewaters, DAF sludges, and poultry composts.
Consequently, our discussion will focus on the production and composition of
poultry manure and litter, although some information on dead poultry composts
will be provided because of the emerging importance of this issue.

A. POULTRY
PRODUCTION
OPERATIONS
AND TYPES
OF WASTE
The major poultry production operations include broiler chickens, turkeys,
and eggs (layer chickens). Broilers account for approximately 80% of the poultry
meat produced in the United States and 72% of the production on a worldwide
basis (Economic Research Service, 1992). Other types of poultry operations include breeders, used to produce eggs for broiler and layer operations; pullet
replacement operations that produce chickens for layer and breeder operations;
and miscellaneous poultry such as ducks, geese, and pigeons. The production
facilities used for all poultry operations are similar and, for all practical purposes, today consist solely of total confinement housing. Some limited semiconfinement or free-range poultry operations exist, but from a poultry waste
management perspective, the vast majority of manures, litters, sludges, and
composts originate from broilers, layers, and turkeys produced in total confinement housing.
Two types of confinement housing are commonly used for poultry operations:
(1) caged pit systems and (2) floor/litter systems. A variety of confinement designs exist, but the houses illustrated in Fig. 2A are reasonably typical examples
of these two systems. Caged pit systems are most commonly used for layer or
pullet operations and consist of cages suspended above either a deep or shallow
pit. Manure from the birds falls into a pit, where it is removed periodically by
scraping or flushing. Caged pit manure contains no bedding material and is nor-

,


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