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I. Poultry Waste Management: Contemporary Issues

I. Poultry Waste Management: Contemporary Issues

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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

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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-



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