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FY 2011 Annual Report

National Program 214—Agricultural & Industrial Byproducts

Introduction

According to the National Agricultural Statistics Service, over one billion tons of 

agricultural (e.g., manure), municipal (e.g. biosolids), and industrial (e.g. coal 

combustion products) wastes with potential uses in agriculture are generated annually in 

the United States. Many of these materials are spread, sprayed or otherwise applied to 

agricultural land because of the benefits they provide. These benefits include: providing a 

nutrient source for crops; improving soil chemical, physical and biological properties; 

improving soil water storage and use; reducing movement of contaminants to water and 

air; and reducing production costs and energy use. However, improperly managed 

manure and other byproducts can pose a threat to soil, water and air quality, and to 

human and animal health.

The goal of the Agricultural and Industrial Byproducts National Program is to develop 

and evaluate management practices and systems, control technologies, and decision tools 

to allow producers and their advisors to (1) use manure and other byproducts effectively 

and safely while protecting the environment and human and animal health and (2) 

provide policy-makers and regulators with information and tools to establish appropriate 

conservation and environmental credit trading programs, and make environmental 

protection decisions. To achieve this goal, this National Program is focused on four major 

areas of research: atmospheric emissions, nutrient management, pathogens and 

pharmaceutically active compounds, and municipal and industrial byproducts. 

Sustainable agriculture depends on effective management of manure and byproducts. 

Selected accomplishments from these four components are described in the following 

section.

Nutrient Management 

The utilization of nutrients in manure in an environmentally sustainable manner is one of 

the critical management issues facing livestock producers. Movement of nutrients in 

excess amounts from manure and other byproducts to soil, water and air can cause 

significant environmental problems. Nitrogen and phosphorus from manure and other 

sources have been associated with algal blooms, accelerated eutrophication of lakes and 

streams, and development of hypoxic zones in the Gulf of Mexico. ARS scientists are 

conducting research to develop management practices, control technologies, and decision 

tools for effective agricultural use of nutrients from manure and other byproducts, while 

protecting environmental quality and public health.

Selected Accomplishments

Beneficial use of nickel (Ni) hyperaccumulator plant as a nickel fertilizer. Research 
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by ARS pecan nutritionists in Byron, Georgia has shown that severe Ni deficiency has 

occurred in pecans in the U.S. Typically, Ni sulfate is marketed as a Ni fertilizer for 

crops such as pecans that need supplemental Ni. Previous research has shown that the 

plant Alyssum is a hyper accumulator of Ni from soil. Research was conducted to 

evaluate the use of Ni extracted from high-Ni soils by Alyssum Ni hyperaccumulator 

biomass as an alternative Ni fertilizer. The Alyssum extract was just as effective as the Ni 

sulfate chemical, and could be produced at far lower cost. Use of ground biomass to 

fertilize pecan and other crops which respond to fertilizer Ni could become an organic 

farming practice.

Midwest cropping system effects on soil quality. Cropping systems may improve or 

decrease soil quality depending on the specific crop rotation, nutrient amendments, and 

tillage practices employed. An ARS researcher in Marshfield, WI, collaborated with 

Univ. of Wisconsin researchers to determine the effect of six cropping systems in the 

Wisconsin Integrated Cropping Systems Trial on soil properties after 18 years of 

continuous treatments. Treatments included three grain-based systems (continuous corn 

and two grain rotations), two forage-based systems (organic and conventional), and a 

grass-legume pasture. Results showed that different Midwest long-term cropping systems 

have significant effects on most chemical, physical, and microbial soil properties (soil 

quality indicators). In particular, the intensively managed grass-legume pasture was 

higher in most soil quality indicators than all other corn or forage-based systems. The 

alfalfa-based systems had higher levels of soil carbon and nitrogen and some physical 

variables than did the grain-based systems but soil quality indexes were not different. 

There were few differences in soil quality parameters between the conventional and

organic dairy cropping systems, a result explained by the fairly similar crop rotations and 

manure inputs. Overall, on these productive, high-organic matters, prairie-derived soils 

under good management, all of the cropping systems in this study maintained an 

acceptable level of soil quality.

User-friendly model developed to predict annual phosphorus loss in runoff. Nonpoint source pollution of fresh waters by agricultural phosphorus (P) can limit water use 

for drinking, recreation, and industry. An ARS researcher at Madison, WI developed and 

validated a user-friendly spreadsheet model (Annual P Loss Estimator -APLE) to predict 

long-term changes in soil P and P loss in runoff for a wide variety of agricultural 

conditions. APLE is especially designed to assess the impact of manure management, 

including grazing or mechanical application, surface application or incorporation, rate 

and timing of manure application, and manure P content as a function of animal diet. 

Parts of the model have been incorporated into the WI P Index, and the model is being 

used to help evaluate and improve predictions by other P Indexes, which are used by 

producers and their consultants across the US to comply with the USDA 590 nutrient 

management standards.

Liming marginal acidic soils may be unnecessary if using poultry litter for cotton 

fertilization. Soils with borderline acidity have to be limed to correct the low pH before 

planting cotton or other row crops. But liming may not be necessary if using poultry 

manure in place of conventional synthetic nitrogen fertilizers. ARS scientists in the 
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Genetics and Precision Agriculture Research Unit at Mississippi State, MS, studied the 

productivity of cotton fertilized with manure versus a commercial nitrogen fertilizer in an 

upland soil with marginal soil acidity. Their results showed fertilizing with ammonium 

nitrate, an inorganic nitrogen fertilizer, further acidified the soil, elevated leaf manganese 

concentration to potentially toxic levels, and reduced lint yield. Poultry manure, unlike 

ammonium nitrate, maintained or reduced acidity of the soil, prevented the elevation of 

tissue manganese concentration, and improved lint yield. Fertilizing with poultry litter 

makes liming unnecessary for profitable cotton production in soils with marginal soil 

acidity and productivity.

Poultry manure application time impact. Although spring-applied litter has the best 

agronomic response, this is often not practical because of typical weather patterns in the 

southeast, thus forcing producers to apply broiler litter in the fall. However, fall 

application of broiler litter before a winter fallow results in substantial leaching losses of 

nitrogen (N) and reduces the potential fertilizer value of the manure. ARS scientists in the 

Genetics and Precision Agriculture Research Unit at Mississippi State, MS, studied the 

impacts of a cover crop of winter rye on fall application of litter. Overseeding a cover 

crop to fall-applied broiler litter synchronized available N with crop needs, maximized N 

use efficiency, and minimized the risks of leaching losses of N. This practice helps fill 

critical gaps in understanding whether detrimental effect of fall-applied broiler litter can 

be mitigated by a combination of cover cropping strategies. The management practice 

positively impacts the agronomic and economic aspects to the farmers and is currently 

being implemented in some areas in the region. A module based on this work was 

selected and written into a Continuing Education (CEU) article for Crops & Soils 

magazine and went out to approximately 14,000 certified crop advisers and soil scientists. 

Url is: 

http://www.magnetmail.net/actions/email_web_version.cfm?recipient_id=720941971&m

essage_id=1354045&user_id=Soc_Agrnmy.

New application technology to band poultry litter beneath the soil surface reduced 

nutrient losses in runoff. Use of poultry litter as a soil amendment often results in 

excessive nutrients in runoff water. ARS scientists at the USDA-ARS National Soil 

Dynamics Laboratory (NSDL) recently developed an experimental implement to place

poultry litter beneath the soil surface. Use of this implement to subsurface apply poultry 

litter in soil can potentially reduce the impact that nitrogen (N) and phosphorus (P) loss 

from poultry litter has on water quality. Rainfall simulation studies were performed to 

evaluate how subsurface application of poultry litter in a bermudagrass pasture would 

impact nutrient losses in surface water runoff at two field sites containing soil from the 

Piedmont and Coastal Plain regions of the southeastern U.S. Subsurface banding of 

poultry litter was compared to surface applied poultry litter, inorganic fertilizer, and a 

nonfertilized control. Subsurface banding poultry litter reduced the impact of N and P 

loss in surface water runoff to levels observed in the non-fertilized pasture.

Plant growth-promoting rhizobacteria improved plant uptake of nitrogen.

Rhizobacteria are root-colonizing bacteria that form mutually beneficial relationships 

with many plants. Previous research has demonstrated that plant growth-promoting 
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rhizobacteria (PGPR) can potentially increase plant growth. It has been speculated that 

one of the mechanisms for this is stimulated nitrogen (N) uptake by plant roots exposed 

to PGPR. Specifically, it is believed that the increased plant N is a result of increased 

fertilizer N utilization efficiency. ARS scientists at the USDA-ARS National Soil 

Dynamics Laboratory (NSDL) conducted studies that demonstrated PGPR could enhance 

plant uptake of N. Results showed that the dry biomass and N uptake in plants which 

received 70% to 90% of recommended N fertilizer with PGPR inoculation was 

comparable to plants that received full rates of fertilizer without PGPR. These results 

indicate that application of PGPR could be used to reduce fertilizer N application needed 

for crop production.

Managing slurry manure based on its carbon-to-phosphorus composition.

Determining the fertilizer value and optimal amount of manure to apply to a crop in 

phosphorus-limiting manured cropping systems requires accurate knowledge of manure 

composition, the phosphate content, and conversion rate of organic phosphorus forms to 

the soluble phosphate by microbes under the conditions existing at the site of storage 

before land application. ARS scientists in Beltsville, MD demonstrated the linkage 

between organic-mineral phosphorus conversion to the manure carbon-to-phosphorus 

composition. As the ratio widened, the conversion of insoluble organic phosphorus to 

soluble phosphate increased and phosphate accumulated in the slurry regardless of how 

much phosphate is already present. On-farm manure handling and storage conditions 

should be managed to minimize this conversion to soluble forms that are easily carried 

away in water by adjusting the carbon content (manure solids) in slurries manure solids to 

reduce the slurry's carbon-to-phosphorus ratio and lower risks of high levels of mobile 

and easily lost phosphate to runoff when these manures are land-applied. 

Supplementation of phosphorus for developing replacement heifers: bone 

development. When phosphorus is fed to cattle in amounts greater than what they can 

utilize, the excess is excreted in the manure. If phosphorus-rich manure is later spread on 

farm fields to provide nutrients for growing crops, it also may cause an excess of 

phosphorus in runoff that can promote the undesirable growth of algae in lakes. For 

growing dairy heifers, phosphorus is essential for bone growth and development. The 

amount of dietary phosphorus needed in dairy heifer diets is very similar to that found 

naturally in many forages comprising typical heifer diets; this suggests that adding 

supplemental phosphorus to heifer diets may not always be necessary. However, no longterm studies addressing this issue exist; therefore, a study was conducted by University of 

Wisconsin and USDA-ARS scientists at Marshfield (WI) with dairy heifers ranging from 

4 to 22 months of age. Dairy heifers were fed diets with or without supplemental 

phosphorus resulting in dietary phosphorus concentrations of 0.29 or 0.39%. Results 

show that phosphorus supplementation for developing replacement heifers had minimal 

effect on the extent of frame development, bone density, or bone metabolism. Potentially, 

this information will help dairy producers and nutritionists formulate heifer rations that

contain adequate, but not excessive, amounts of phosphorus so that the growth needs of 

the heifers are met without adding excess phosphorus to the environment.
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Pathogens and Pharmaceutically Active Compounds

Pathogens and pharmaceutically active compounds in manure, biosolids, and other 

byproducts can be transmitted to animals and humans through food supplies, water and 

possibly air. Livestock and poultry can also be re-infected not only via water and air, but 

from other vectors such as birds, rodents and insects. The most significant of the manureborne zoonotic pathogens are the protozoan parasites Cryptosporidium parvum and 

Giardia duodenalis, and the bacterial pathogens Salmonella, Campylobacter, Escherichia 

coli, and Listeria monocytogenes. Pharmaceutically active compounds such as hormones 

and antibiotics may also be present in animal waste and disseminated in the environment. 

The potential for serious health effects both on and off the farm, the lack of knowledge 

about pathogen survival in manure during collection, storage, treatment and application, 

and uncertainty about fate and transport of pathogens in soil, water and air from the 

animal production site or manure application area, clearly point to the need for research 

on these issues.

Selected Accomplishments

Design and use of a Salmonella vaccine strain to reduce Salmonella presence and 

disease in swine. The foodborne pathogen Salmonella is a leading cause of food-related 

disease and death in the U.S. Salmonella are often present in the gastrointestinal tracts of 

both wild and domesticated animals. For example, Salmonella can be isolated from over 

50% of swine production facilities. However, pigs that have Salmonella usually do not 

show clinical disease, but because they carry the bacteria in their gastrointestinal tracts, 

they are a potential food safety risk for pork consumers. Agricultural Research Service 

researchers in Ames, Iowa, designed and evaluated a Salmonella vaccine strain in swine 

to determine if vaccinated pigs would have reduced disease severity and gastrointestinal 

colonization upon exposure to a pathogenic Salmonella strain. Disease severity, 

Salmonella shedding in the swine feces, and Salmonella gastrointestinal colonization 

were significantly reduced in the vaccinated pigs compared to the non-vaccinated pigs. 

This Salmonella vaccine is a promising intervention for the reduction of Salmonella in 

swine, resulting in enhanced pork safety and decrease potential risks for the consumer.

Mathematical model for pathogen transport and retention developed. Existing 

mathematical models to simulate the movement of pathogens through agricultural soils 

and groundwater do not provide reliable predictions even under relatively simple, well 

defined conditions. Researchers at the USDA-ARS US Salinity Laboratory and the 

University of California at Riverside have developed a mathematical model for pathogen 

transport and retention. The model provides a clear conceptual explanation for many 

incompletely understood observations of pathogen transport and retention in soils, and 

helps to identify areas where additional research and theory development are still needed. 

This information will be of interest to scientists and engineers concerned with predicting 

the fate of pathogens in soils and aquifers.

Animal diet affects manure-borne pathogen transport. Animal diet can affect the 

physical, chemical, and microbiological composition of the resulting manure. For 
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example, the feeding of distiller's grains as part of a finishing diet for cattle is associated 

with higher numbers of the pathogenic E. coli O157:H7. Little is known, however, about 

the impacts of diet on the transport of manure-borne microorganisms once manure is 

land-applied. ARS researchers in Lincoln, NE, investigated bacterial and parasitic 

bacterial virus transport in runoff from fields amended with manure from animals fed 

either corn or 40% wet distiller's grain. They determined that feeding 40% wet distiller’s 

grain increased the potential for viruses that specifically infect bacteria to move into the 

environment. This information is being used to develop land application practices that 

incorporate the use of manure as a nutrient source for crop production while minimizing 

potential adverse environmental impacts.

Cattle feedlot pens are more than just uncomposted manure. The public and much of 

the food safety community tend to think of E. coli O157:H7 as being synonymous with 

cattle feces and the feedlot pen that collects the feces is thought of as being just packed 

uncomposted manure. Using DNA-based bacterial community profiling, ARS researchers 

in Lincoln, NE demonstrate that the bacterial communities in the feedlot pen are distinct 

from those of the fecal source material. Fecal microorganisms face a challenging 

environment on the pen surface compared to the animal gastrointestinal tract that selects 

for the persistence of some microorganisms over others. A better understanding these 

environmental challenges facing fecal pathogens like E. coli O157:H7 can lead to new 

ways of controlling them.

Microbial risk analysis: manure vs. biosolids. The presence of microbial pathogens in 

manure and biosolids has long been recognized as a drawback to use of these waste 

residuals in settings where the public could be exposed to the pathogens. Regulations and 

recommendations in place for 20 years have minimized exposures, but recent national 

and foreign outbreaks of enteric illness call into question our understanding of pathogen 

inactivation and risk. ARS scientists in the Genetics and Precision Agriculture Research 

Unit at Mississippi State, MS, conducted an in depth quantitative microbial risk analysis 

using current (local), historical, and national data sets for various manures and municipal 

Class B biosolids. Risks were analyzed for a number of situations, including occupational 

and public exposures (raw vegetable consumption, aerosol exposure, etc.). Using 

empirical data and exposure modeling, the scientists determined that specific microbial 

risks differed for the respective waste residuals; bacterial risks are greater for manure, 

while viral risks are greater for biosolids. Using these models, the scientists estimated 

that for public risks to approach significant levels, a ‘regrowth’ step must occur that 

increases pathogens to detectable outbreak levels after residuals are applied in the 

environment; so applying residuals as field crop fertilizer under conditions that preclude 

or minimize pathogen regrowth poses minimal public risk. This research provided a first 

of its kind comparison of the two residual types and highlighted the need for more 

microbial incidence data.

Pathogen survival after land application of manure. Enteric pathogens on soils and 

plants fertilized with manure can pose risks to grazing animals and humans if the 

pathogens survive or grow in the soil or plant environments. ARS scientists at the 

Genetics and Precision Agriculture Research Unit at Mississippi State, MS, studied the 
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survival of naturally occurring bacterial pathogens and fecal indicator bacteria in swine 

manure lagoon effluent during and immediately following land application in a 

commercial farming operation. Bacteria were monitored in aerosols, soil, and on grass 

leaves. Survival of most indicator bacteria and pathogens was intermittent and most 

bacteria were either killed within 72 hours of land application or were diluted in the 

application process to levels below cultural detection limits in the soil and grass 

environments. Aerosolized pathogens were rarely detected. This study established that 

bacterial pathogens known to be present in swine manure were rarely detected in 

environmental samples after land application of lagoon effluent suggesting that: 1) land 

application of lagoon effluents dilutes bacterial pathogens and mitigates potential risks; 

and 2) efforts to track pathogens, such as from an outbreak of enteric illness, back to 

manure-contaminated plants or soil will require development of more sensitive detection 

techniques than those currently available.

Poultry litter provides biological control of spores of plant pathogenic fungi in soil.

Species of Bipolaris, Curvularia, and Exserohilum are plant disease-causing fungi that 

attack leaves and stems of many turfgrasses and cereal crops and also invade soil where 

they can infect roots and kill plants. The potential of poultry litter to provide biological 

control of spores of four species of these fungi in soil was evaluated for the first time. 

ARS scientists in the Genetics and Precision Agriculture Research Unit at Mississippi 

State, MS, placed spores into porous nylon membranes, incubated them in moist soil for 

two weeks with and without poultry litter added at 4% and 8% by weight, retrieved 

spores, and evaluated their ability to germinate. In repeated experiments, spores of all 

species incubated in soil without litter germinated at frequencies of 70-87% following 

their retrieval. When spores were incubated in soil containing 4% litter, germination was 

reduced to 2-42% among the four fungi, and with 8% litter, it was further reduced to 1-

17% with many spores visibly fragmented or disintegrated. These results indicate that 

poultry litter may provide significant biological control of spores of four species of plant 

pathogenic fungi when incorporated into soil, but its effectiveness as a biological control 

material differs among the species.

Comparative die-off of E. coli 0157:H7 (Escherichia coli) and fecal indicator 

bacteria in pond water. E. coli 0157:H7 is the cause of bloody diarrhea in humans and 

has been the cause of large-scale foodborne and waterborne illnesses worldwide. Several 

researchers have reported on the persistence of this pathogen in surface waters of 

watersheds containing beef and dairy cattle, which are often the principal sources of this 

pathogen. Researchers at the J. Phil Campbell, Sr., Natural Resource Conservation Center 

in Watkinsville, GA designed experiments that demonstrated die-off rates of indicator 

bacteria were several times greater than the die-off rate of E. coli 0157:H7. Unlike the 

fecal indicator bacteria, the strain of E. coli 0157:H7 the researchers used in their 

experiments appeared less susceptible to the effects of solar ultra violet (UV)-radiation 

and predation from the natural microbial community. The greater persistence of E. coli

0157:H7 in environmental surface waters can result in infectious levels in waters when 

the levels of the indicator organisms are below the criterion of water impairment. This is 

important information for regulatory agencies
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Concentrations, viability, and species distribution of Cryptosporidium in waste 

lagoons of swine operations in the Southern Piedmont and Coastal Plain of Georgia.

Waste lagoons of large-scale swine operations have been implicated as a potential source 

of the protozoan parasite Cryptosporidium that is pathogenic to humans. Applications of 

lagoon effluent to cropped and hayed fields are potential sources of surface water 

contamination and risks to public health. Based on samples of the waste lagoons at 10 

swine operations, scientists at the J. Phil Campbell, Sr., Natural Resource Conservation 

Center, Watkinsville, Georgia, and Cornell University, Ithaca, New York showed that 

Cryptosporidium parasites were present in all of the waste lagoons. The viability of the 

Cryptosporidium ranged between 2 and 12% of the total number of parasite eggs detected 

in the samples. The genetic analysis of these parasites indicated that 75% of 

Cryptosporidium parasites observed were specifically adapted to pigs. These parasites 

would only be pathogenic to humans with compromised immune systems. Only five of 

the 407 samples were identified as the species of Cryptosporidium that is pathogenic to 

healthy humans. Results of this research indicate that although swine waste lagoons are 

almost surely contaminated with Cryptosporidium parasites, the likelihood of the 

presence of the genetic type that is pathogenic to humans is relatively low. Thus, the 

human health risk associated with Cryptosporidium in swine waste lagoons is relatively 

low. This information can be used by the pork industry, agricultural extension agencies, 

and regulatory agencies to ensure safe application and management of swine waste 

effluent.

Atmospheric Emissions

Air emissions from animal production operations and land application of manure and 

other byproducts include particulate matter, ammonia, volatile organic compounds (that 

cause odor or serve as precursors for ozone formation), hydrogen sulfide, greenhouse 

gases and pathogens. Research is being conducted to: (1) develop new methods and 

improve existing methods to measure particulate matter and gaseous emissions; (2) 

develop and determine the effectiveness and environmental benefits of management 

practices and control technologies to reduce emissions; and (3) develop and test decision 

tools to predict emissions and their dispersion across a range of animal production 

systems, management practices, and environmental conditions. Tools and practices for 

measurement, control and prediction of emissions from animal production operations will 

help provide the scientific background for management, policy and regulatory decisions.

Selected Accomplishments

Combining condensed tannins and borax can reduce production of emission and 

odors from swine manure. Reducing production of greenhouse gases and odorous 

compounds such as hydrogen sulfide is an important goal for large-scale swine 

production operations. Condensed tannins, which are complex phenolic compounds 

naturally found in plants and trees, were studied for their abilities to inhibit bacteria 

present in stored manure. A collaboration of Bioenergy Research Unit scientists at the 

National Center for Agricultural Utilization Research, Peoria, IL, and Michigan State 
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University have demonstrated that tannins isolated from the quebracho tree in South 

America, in combination with borax, will reduce overall gas and hydrogen sulfide 

production from manure slurries studied in the laboratory. These results can now be 

applied towards reducing odors and greenhouse gas emissions from large-scale swine 

facilities. Such reductions are of great interest to swine producers, environmental 

protection agencies, and local residents that live near swine facilities.

Airborne endotoxin and microorganism concentrations decrease rapidly downwind 

from a dairy. Airborne microorganisms could be a human health concerns near dairy 

farms. ARS researches at Kimberly, ID, measured bioaerosol concentrations at a freestall 

dairy to assess concentration changes downwind from the dairy and assess diurnal and 

seasonal variations in concentrations. Results showed that airborne endotoxin and 

bacteria concentrations 150 ft from the dairy could be several-hundred times greater than 

background concentrations. These concentrations decreased to near background 

concentrations at 600 ft downwind. Although bioaerosol concentrations did not have a 

seasonal trend, concentrations did correlate with meteorological factors such as 

temperature and solar radiation. These results suggest a reduced risk for exposure to 

bioaerosols as distance from dairy operations is increased, which is useful information for 

creating offset distances for new residential or commercial developments near dairy 

farms.

Determining the effect of animal diet on air emissions from feedlot surfaces. Air 

emissions from animal feeding operations affect the environment and pose potential 

nuisance concerns to downwind neighbors. Based on laboratory studies, there is evidence 

that animal diet impacts the types and amounts of air emissions from manure. ARS 

researchers at Clay Center, NE, developed a method for evaluating the spatial distribution 

of air emissions at the field-scale, and determined that diet had an effect on the spatial 

distribution, types and quantities of odorants produced by manure. Having the ability to 

predict the locations of elevated air emissions will allow producers to use cost-effective 

precision management techniques to minimize air emissions from feedlot surfaces.

Ammonia emissions from dairy farms and beef feedlots: A review. Ammonia is a gas 

composed of nitrogen and hydrogen; thus, ammonia emissions from cattle feedlots and 

dairies are a significant loss of potential fertilizer nitrogen from animal feeding 

operations and a source of potential environmental problems. A group of experts in the 

field of ammonia emissions, including scientists at the ARS Conservation and Production 

Research Laboratory, Bushland, TX, and other ARS and university scientists, 

collaborated to produce a comprehensive review that focused on ammonia chemistry, 

physics, animal interactions, measurement methodologies, emission sources and 

magnitudes, and modeling of emissions. This big-picture approach was published as an 

invited review article in the Canadian Journal of Animal Science and gives scientists,

regulators, action agencies, and policy makers state-of-the-science knowledge to help 

understand the factors that control and contribute to ammonia emissions and how they 

may be controlled.

Methane emissions from Southern High Plains dairy wastewater lagoons in the 
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summer. Methane is a powerful greenhouse gas that can contribute to global climate 

change. A major source of methane at dairies may be wastewater lagoons; however, the 

contributions of methane from dairy lagoons in the southern High Plains have not been 

quantified. Scientists at the ARS Conservation and Production Research Laboratory, 

Bushland, TX, teamed with researchers at Texas AgriLife Research, West Texas A&M 

University, and New Mexico State University to conduct an intensive and comprehensive 

study at a 3,500-cow dairy that included measuring methane emission from lagoons. 

Daily release of methane from the lagoons averaged 402 kilograms per hectare, or 210 

grams of methane released for each cow in the dairy. These results show that uncovered 

wastewater lagoons can be a significant source of methane at dairies and offer producers 

a potential management method to reduce methane losses.

Seasonal and annual ammonia emissions from southern High Plains beef cattle 

feedyards. Ammonia that escapes as a gas from beef cattle feedyards is a loss of valuable 

fertilizer nitrogen and can negatively impact sensitive ecosystems and degrade air quality. 

However the quantity of ammonia emitted from feedyards and the factors controlling 

those losses have been poorly understood. ARS researchers from the Conservation and 

Production Research Laboratory, Bushland, TX, in collaboration with researchers at West 

Texas A&M University and Texas AgriLife Research, continuously measured ammonia 

emissions from two feedyards over a two-year period. The major factors affecting 

ammonia emissions were ambient temperature and dietary crude protein concentration. 

Averaged over the two years of the study, 52% to 59% of nitrogen in the feed was lost as 

ammonia at the two feedyards. These results are the most extensive measures of ammonia 

emission from feedlots available, and they provide an important database that can be used 

by scientists to validate and verify process models of emissions, provide the cattle 

industry with accurate science-based ammonia emissions data to meet regulatory 

requirements, and give regulators more accurate, comprehensive data from which to build 

ammonia emissions inventories.

Redesigned ammonia scrubber. Ammonia, dust, odiferous compounds, and pathogens 

are emitted in the exhaust air from poultry and swine facilities. During the past year, ARS 

researchers from Fayetteville, AR, redesigned an ammonia scrubber for purifying air 

being exhausted from these facilities. This was accomplished with the aid of engineers 

and scientists brought in from Delaware, Mississippi, Oklahoma, and Tennessee. The 

new design allows for improved removal of ammonia from the air while increasing the 

airflow through the scrubber. This technology will now reduce ammonia concentrations 

emitted from poultry houses by 75% or more.

Novel bacteria for wastewater treatment. Investigators at Florence, SC, discovered a 

novel bacterium having the characteristics of oxidizing ammonia and releasing nitrogen 

gas under anaerobic conditions. The novel bacterial strain Candidatus Brocadia 

caroliniensis may be used for the treatment of wastewater having undesirable levels of 

ammonia, including agricultural, industrial, or municipal wastewaters. Compared to 

conventional biological nitrogen removal methods, this microbial method uses 60% of 

the energy normally required for aeration and does not require external carbon addition. 

In addition, by-products do not include greenhouse gases (methane and nitrous oxide). 
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This leads to a significant decrease in operational costs and provides possible 

environmental credit benefits for the users of this new technology.

Systems and methods for reducing ammonia emissions from liquid effluents and for 

recovering ammonia. ARS researchers at Florence, SC, invented new methods for the 

removal, recovery and use of ammonia from ammonia containing liquid effluents such as 

animal and municipal wastewater. The invention produces a concentrated non-volatile 

ammonium salt. The potential benefits are reduced ammonia emissions from liquid 

manure, cleaner air inside the barns with benefits to animal health, and recovery of 

ammonia as a concentrated liquid nitrogen reusable as a plant fertilizer.

Byproducts

Each year millions of tons of agricultural, municipal and industrial byproducts are 

generated in the United States. These materials are frequently considered to be wastes 

and are often disposed in landfills. However, many of these materials have

characteristics that make them potentially useful to improve soil properties for enhanced 

crop production, to prevent movement of contaminants to critical bodies of water, and to 

lower energy inputs in agricultural systems. Research is being conducted to determine 

benefits and risks of the materials, to develop and evaluate the effectiveness and 

economic benefits of byproduct-based management practices and control technologies, to 

document the environmental benefits of using these materials, and to develop guidelines 

for specific uses.

Selected Accomplishments

Develop new, value added products from industrial byproducts (coal ash). As a

result of the bombing of the Alfred P. Murrah Federal Building in downtown Oklahoma 

City on April 19, 1995, new regulations on licensing, sale and shipping of ammonium 

nitrates were developed to prevent a possible repeat of the Oklahoma bombing. 

Additionally, several government agencies are interested in reducing the value of 

ammonium nitrate as an ingredient in bombs by encapsulating ammonium nitrate in 

byproducts such as fly ash and flue gas desulfurization gypsum that are produced from 

electrical power plants. Research by an ARS scientist at Beltsville, Maryland, has 

demonstrated in greenhouse and field studies, that encapsulated ammonium nitrate was as 

effective as un-encapsulated ammonium nitrate for crop production, without increasing 

unwanted metals concentrations in soil and plants from the byproducts.

A better use for waste chicken feathers. Over four billion pounds of chicken feather 

waste is generated by the U.S. poultry industry each year. Although feathers are typically 

disposed of in landfills, a new use for feather fiber is as a component of biopolymers. The 

primary advantage of feather-based biopolymers is that they reduce the use of petroleumbased feedstocks. However, an added benefit of some biopolymers is that they degrade 

relatively quickly under composting conditions. Since the fate of feather-based 

biopolymers during composting has not been studied previously, the aim of this study 
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was to characterize the biodegradability of two biopolymers containing different amounts 

of poultry feather fiber. Results from experiments conducted by ARS scientists in 

Beltsville, MD showed that feather fiber was not degraded in either biopolymer after 

composting feather-fiber biopolymer fragments under standard conditions (60 days at 135 

F). Raw feather fiber (primarily composed of the protein keratin) is itself quite resistant 

to microbial breakdown. However, results from other studies have shown that raw feather 

fiber can be degraded using special keratinase-producing fungi and bacteria. Additional 

studies are needed to see whether these organisms can speed the degradation of featherfiber bioplastics.

Net energy values of wet distiller's grains. The use of wet distiller's grains, a byproduct 

of the grain-based bioethanol industry, in beef cattle finishing diets has increased 

exponentially in the past few years; however, the true net energy values have not been 

determined. Using a respiration calorimetry system, ARS researchers at the Conservation 

and Production Research Laboratory, Bushland, TX, determined that the net energy for 

maintenance and net energy for gain values of wet distiller's grains were similar to that of 

steam-flaked corn. In addition, when the diets were formulated to be equal in total fat 

content, feeding wet distiller's grains did not affect enteric production of the greenhouse 

gas methane. These net energy values can be used by nutritionists to better formulate and 

balance finishing diets and to better predict animal performance.

Turning wood industry waste into nursery growing media. WholeTree (WT) and 

Clean Chip Residual (CCR) are potential new nursery substrates that are byproducts of 

the forestry industry containing high wood content. Initial immobilization of nitrogen is 

one concern when using these new substrates; however, the addition of composted 

poultry litter (CPL) to substrates containing high wood content could balance initial 

nitrogen immobilization and provide an inexpensive fertilizer source for growers. ARS 

scientists at the USDA-ARS National Soil Dynamics Laboratory (NSDL) conducted 

experiments on these alternative substrates with poultry litter addition in nursery

production. Results indicate that nitrogen immobilization can be overcome in WT and 

CCR substrates mixed 6:1 on a volume basis with composted poultry litter. Use of 

composted poultry litter in WT and CCR substrates could provide an alternative to 

traditional pine bark and peat based combinations in container production while 

providing poultry producers an environmentally sound means of waste disposal.

Biochars made from manures and crop residues improve soil carbon sequestration, 

water storage, fertility, and remove harmful chemicals. Investigators at the ARS 

Florence location produced biochars, a charcoal-like product, during carbonization of 

manure and plant waste materials using both thermal and hydrothermal processing. Both 

of these processes were optimized to produce biochars with diverse chemical and 

physical properties. Laboratory research showed that biochars made from nut shells were 

effective at increasing soil carbon sequestration while biochar made from grasses 

increased soil water storage. Manure biochars contained plentiful plant nutrients such as 

nitrogen, phosphorus, and potassium, but were blended with other plant-based biochars to 

produce a more nutrient balanced fertilizer-like product. Location scientists also 

discovered that hydrochar, the biochar made from hydrothermally processing poultry 
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litter, can be used as an environmental adsorbent for effectively removing harmful 

chemicals such as endocrine disrupting chemicals and estrogens. Production of these 

biochars and their blends leads to an alternative use of agricultural byproducts that can 

increase soil carbon sequestration and water storage, provide essential plant nutrients and 

reduce levels of contaminants in soils.

Risk assessment for beneficial use of flue gas desulfurization (FGD)-gypsum in 

agriculture. ARS researchers and others have been conducting research to evaluate the 

beneficial use of FGD-gypsum in agriculture. ARS is cooperating with the USEnvironmental Protection Agency in conducting a full risk evaluation of this use to 

provide information needed to make regulatory decisions about FGD-Gypsum use as 

fertilizer and soil conditioner. The electrical generating industry manufactures FGDgypsum by removing sulfur dioxide from exhaust gases. Field tests have been being 

conducted to assess the ability of FGD-gypsum to reduce the runoff of phosphate from 

soils including soils amended with poultry litter on the surface of hay fields. To date, 

research has shown that application of FGD-gypsum can significantly reduce runoff 

phosphorus and arsenic. Other studies have not found any adverse effects of amending 

soils with FGD-gypsum and have not shown any differences in soils amended with FGDgypsum compared to those amended with mined gypsum.