Nutrient Management. Movement of nutrients in excess amounts from manure and other byproducts to water and air can cause significant environmental problems. These nutrient losses to the environment can occur at the production site, during storage and during and after field application. Nitrogen and phosphorus from manure and other sources have been associated with algal blooms and accelerated eutrophication of lakes and streams. Utilization of nutrients in manures in an environmentally sustainable manner, is one of the critical management issues facing the U.S. livestock industry. Research is being conducted in a variety of areas to protect soil, water, and air from excess nutrients in manure. This research includes more efficient use of nutrients in animal feed; improved technologies for manure handling, storage and treatment; improved tests for nutrients in manure and soil treated with manure; soil threshold nutrient levels for protection of water quality; development of methods to identify areas on a farm or in a watershed that are most susceptible to nutrient losses; improved methods for precise application of manure; and integrated animal and cropping systems to effectively use and recycle nutrients.
Atmospheric Emissions. Three types of emissions (gases, particulates, and aerosols) affect air quality changes around animal operations, manure storage areas, and manure field application sites. Gases of particular interest include ammonia, odorous compounds, and greenhouse gases such as methane, carbon dioxide, and nitrous oxides. Ammonia emissions appear to have the greatest potential for adverse environmental and health impacts, while generation and transport of malodorous compounds provoke the greatest public concern. To develop cost-effective methods of emissions reduction and control improved methods to measure and quantify emissions will be required. 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.
Pathogens. Pathogens and pharmaceutically active compounds in manure can be transmitted to other animals and humans through food supplies and water. Production of fresh fruit and vegetables using manure or irrigating with wastewater could be mechanisms of pathogen transfer. 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 sensitive detection and accurate quantification of pathogens and pharmaceuticals in complex matrices such as manure and soil will be needed.