Devise Animal Production and Processing Systems that Sustain or Improve the Environment
Livestock and poultry production in the United States has become increasingly concentrated in confinement facilities often located on small land areas. Manure generated at approximately 280,000 animal feeding operations around the country can be used as a nutrient source for crops, to improve soil properties, and for alternative uses such as energy production. However, improperly managed manure poses a threat to soil, water and air quality, and to human and animal health. The main problems associated with manure management are: nutrient enrichment of soil and water; atmospheric emission of odors, ammonia and greenhouse gases; and pathogens and pharmaceutically active chemicals such as antibiotics that may contaminate food and water supplies. A cooperative effort involving research, extension, and education will be required to provide animal producers with cost-effective management practices, treatment technologies and decision tools to address these problems and to help them comply with impending environmental regulations. CSREES through its land grant university partners has approximately 400 CRIS projects that at least partially focuses on animal manure management. ARS has a National Program on Manure and Byproduct Utilization that involves research at 18 laboratories across the US.
Objective 1: Develop Better Scientific Measures and Diagnostic Tools To Protect Water, Soil, and Air Quality.
Comprehensive nutrient management practices are needed at the farm and watershed scale to protect water quality. Research is being conducted to develop: improved tests for nutrients in manure and soil treated with manure; soil threshold nutrient levels for protection of water quality; methods to identify areas in a watershed susceptible to nutrient losses; improved methods for precise application of manure; and models to predict nutrient inputs to sensitive bodies of water based on soil conditions, hydrology, weather and management practices.
Several advances have been made in this area. CSREES scientists have developed infrared technology to determine the nutrient content of wastewaters. ARS scientists are determining the rate of conversion of organic nitrogen in manure to forms that can be used by crops (mineralization) under a range of soil and environmental conditions. A decision tool will be developed to help producers determine manure application rates that will meet crop nitrogen needs while avoiding contamination of water. ARS and CSREES scientists are working with the Natural Resources Conservation Service (NRCS) to develop and refine a tool, the Phosphorus Index, to identify critical areas on a farm or in a watershed that are susceptible to phosphorus losses to surface water. The Index identifies and ranks the vulnerability of soils, landscapes and management practices to phosphorus loss in runoff. The Index is being used by NRCS field staff to identify sensitive areas and target management alternatives to reduce environmental risk. Many states plan to use the Phosphorus Index to guide manure application decisions.
Improved methods to measure and quantify emissions will be required to develop cost-effective methods of emissions reduction and control. A greater understanding also will be needed of the mechanisms responsible for emissions, emission rates resulting from a variety of animal management practices, and methods to predict dispersion and transport of emissions across the landscape. ARS scientists have developed a small passive air sampler containing a solid-phase microextraction device to quantify volatile sulfur, amine and fatty acid compounds. Since gases captured by the air sampler can be measured at the parts per billion level using gas chromatography/mass spectrometry, the device can be used to determine the effectiveness of emission reduction practices. ARS scientists are developing methods to measure and quantify emissions around animal production facilities, manure storage areas and field application sites using Fourier transform infrared spectroscopy and tunable lasers. One aspect of this study involves measurement of ammonia and volatile organic compounds attached to particulates that are captured downwind of swine production units. This approach will allow potential pathways and form of movement from production facilities to be determined.
CSREES scientists in a number of states have used human odor panels to detect odors emitted from animal production facilities. Progress in the development of an “electronic nose” may eliminate the need for human odor panels. Several multistate committees , with both CSREES and ARS scientists as members, focus on air quality issues: S-275, Animal Manure and Waste Utilization, Treatment, and Nuisance Avoidance for a Sustainable Agriculture; S-291, Systems for Controlling Air Pollutant Emissions and Indoor Environments of Poultry, Swine and Dairy Facilities; NCR-189, Air Quality Issues Associated with Animal Facilities. CSREES and ARS are represented on the USDA Air Quality Task Force that has identified three priority research areas: (1) particulate matter (PM10 and PM2.5), (2) ozone, and (3) odor and odorants.
Research is needed to determine survival, transport, and dissemination of manure pathogens and pharmaceutically active compounds in the environment to assess risks to human and animal health and to develop appropriate control measures. Methods for detection and accurate quantitation of pathogens and pharmaceuticals in complex matrices such as manure and soil will be needed. ARS scientists have developed a new methodology for the separation and detection of E. coli O157:H7 in surface waters. This method will be transferred to other scientists and to commercial water testing laboratories. ARS and CSREES scientists demonstrated that pathogens did not survive in the air over beef cattle feedlots in the Texas High Plains. However, pathogens like Salmonella, E coli O157:H7, and Cryptosporidium parvum where still present two months after being seeded into a manure pile. CSREES and ARS scientists are conducting research to measure and model the fate and transport of pathogens such as E. coli, Salmonella, Campylobacter and Cryptosporidium in soil, water and air.
Objective 2: Design and Demonstrate Production Systems and Management Practices that Reduce any Adverse Environmental Effects of Animal Agriculture
A systems research approach involving all phases of animal feeding; manure handling, storage and treatment; land application; crop production; and conservation practices will be required to reduce or eliminate any adverse environmental effects of animal agriculture. Animal diet and animal nutrition can influence the amount of manure produced, nutrients excreted in the manure and production costs. Current and future research approaches include: defining animal nutritional requirements, diet formulation, modified crops, addition of enzymes to increase nutrient digestibility in feed, and alteration of intestinal microflora. Progress has been made in lowering phosphorus levels in the diet of lactating dairy cows without compromising animal health and performance. Addition of phytase enzyme to the diet of swine and poultry has increased their utilization of phosphorus in grain. Development of grain with phosphorus in more readily digestible forms offers the possibility for more effective use of feed nutrients. Research is being conducted to evaluate alternative levels of fiber from feed grains to help reduce the amount of manure excreted. ARS and CSREES scientists in Texas and New Mexico are conducting cooperative research through the Consortium for Cattle Feeding and Environmental Sciences (CCFES). Scientists within the CCFES have designed a series of 11 experiments to study the effects of dietary protein and phosphorus nutrition on animal productivity, manure production, manure characteristics, ammonia emissions and runoff quality from beef cattle feedyards. These experiments should answer many questions about the effect of cattle feeding operations on environmental quality.
Efficient and cost-effective methods for manure handling, treatment and storage are needed to prevent movement of nutrients, gases and pathogens to soil, water and air. Management practices, treatment technologies, and decision aids are needed to transform or capture nutrients; reduce emissions of ammonia, malodorous compounds and greenhouse gases; kill pathogens; and reduce or eliminate off-site movement of pharmaceutically active compounds. ARS scientists have found that treatment of poultry litter in commercial houses with alum (aluminum sulfate) can lower ammonia emissions and reduce the solubility of phosphorus in manure. This treatment technology improves broiler health while protecting air and water quality. Last year approximately 500 million broilers were produced on alum treated litter.
CSREES and ARS scientists are developing systems of treatment technologies to manage wastewater from swine and dairy operations. Rapid and efficient separation of manure solids from the liquid phase of swine wastewater is a critical step in the development of treatment systems. A solids/liquid separation method based on injection of polyacrylamide polymers to increase solids flocculation and a sand filtration system has been developed. This method has been shown to: reduce suspended solids in the liquid phase by a factor of 60, capture over 80 percent of the organic nutrients in the solid phase where they can be more readily used, and produce removable cakes within 48 hours. A wastewater treatment technology, based on immobilization of nitrifying bacteria inside permeable polyvinyl beads, has been shown to effectively remove ammonia from swine wastewater. This technology has the potential to treat large amounts of ammonia in swine wastewater that would otherwise volatilize and escape to the environment. Alkaline addition to the effluent from this treatment can be used to participate and capture phosphorus, and to kill pathogens. Constructed wetlands have proved to be effective in converting nitrate in wastewater into harmless dinitrogen gas. These and other methods for wastewater treatment need to be further refined, then combined into a system of treatment technologies that can be used as an alternative to anaerobic lagoons.
Agricultural management practices significantly influence the environmental fate of manure nutrients. Management practices such as timing and placement of manure application, grazing management practices, water table control through subsurface drainage, use of cover crops to recycle nutrients, and placement and design of buffers; must be developed to prevent movement of excess nutrients to water and air. ARS scientists have developed a decision tool that will allow producers to identify pasture stocking rates that will protect water quality. Research is being conducted to develop animal production systems that will balance nutrient inputs and outputs at the whole-farm scale.
A number of extension and educational activities have been developed to transfer information about new production systems and management practices to the animal agriculture community. In 1998 the Extension Committee on Organization and Policy (ECOP) and the Experiment Station Committee on Organization and Policy (ESCOP) jointly endorsed a national initiative on animal waste management. One result of this initiative has been the establishment of a network of research or extension contacts in each state who are organized on a regional basis to exchange information and plan programs. A national Livestock and Poultry Environmental Stewardship Curriculum has been developed by scientists from over 15 land grant universities, ARS and NRCS. The Curriculum was released on October 2, 2001 and will be explained at 10 workshops around the country. Research, extension and education projects have been funded through competitive and base fund programs administered by CSREES. The National Center for Manure and Animal Waste Management was funded through the Fund for Rural America program and involves cooperation among 16 institutions around the country.
Objective 3: Invent Technologies that Capture Value from Manure and Processed By-products
A variety of technologies are being developed to capture value from manure. Research is needed to optimize the use of manure for energy production through burning, methane generation or conversion to other fuels. CSREES scientists are developing thermophilic (high temperature) anaerobic digestion methods to produce methane from swine manure. Direct combustion of manure, either alone or mixed with other materials, for energy may be an option in areas with very high livestock or poultry concentrations and limited land availability. CSREES and ARS scientists are conducting research to mix, blend, or co-compost manure with selected industrial or municipal byproducts to produce materials for specialized uses. A landscape mulch produced from a blend of manure and newspaper, can be used for erosion control and grass establishment on lawns, road embankments and golf course fairways. Methods have been developed to concentrate and capture nutrients in manure which can then be used in high value fertilizers for agricultural and horticultural applications. Dried manure has been used as a component of materials used for construction of building walls. Researchers are finding ways to extract carbohydrate and protein fractions from animal manure. The carbohydrate fraction will be used for the manufacture of products such as plastics and antifreeze.