Concern over the enrichment of agricultural runoff with phosphorus (P) from land applied livestock manures has prompted the development of manure amendments that minimize P solubility. In this study, we amended poultry, dairy, and swine manures with two rare earth chlorides, lanthanum chloride (LaCl(3).7H(2)O) and ytterbium chloride (YbCl(3).6H(2)O), to evaluate their effects on P solubility in...

A compilation of N balance data (n = 1801) was partitioned into four groups to define the mean excretion of manure and N and to develop empirical equations to estimate these excretions from Holstein herds. Mean excretion of manure for cows that averaged 29 kg/d of milk production was 3 kg/d per 1000 kg of body weight (BW) more than the value for dairy cows reported by the American Society of Ag...

A protocol using flux chambers was employed to determine ammonia emission rates from different low level area sources (LLAS) including free stalls, open lots, manure composting areas, lagoons and separated solids in a central Texas dairy. Data including ammonia emissions from these sources were collected for summer and winter seasons of 2003. Ammonia concentration measurements were made using c...

Milk production has greatly increased in China recently, with significant impacts on the cycling of nitrogen (N) and phosphorus (P). However, nutrient flows within the changing dairy production system are not well quantified. The aim of this study was to increase the quantitative understanding of N and P cycling and utilization in dairy production through database development and simulation mod...

Management factors affect nutrient loss during animal manure slurry storage in different ways. We conducted a pilot-scale study to evaluate carbon (C) and nitrogen (N) losses from unseparated and digested dairy slurry during winter and summer storage. In addition to season, treatments included mechanical separation of digestate into liquid and solid fractions and bimonthly mixing. Chemical anal...

The Extension Service, United States Department of Agriculture, funded a special project to approach development of extension materials for dairy farmers by systems analysis. Agricultural engineers created video tapes and publications on manure, feed handling, calf housing, and milking subsystems. Dairy scientists created slide-tapes and publications on controlling feed losses during harvest, s...

Computer models are a rapid, inexpensive way to identify agricultural areas with a high potential for P loss, but most models poorly simulate dissolved P release from surface-applied manures to runoff. We developed a simple approach to predict dissolved P release from manures based on observed trends in laboratory extraction of P in dairy, poultry, and swine manures with water over different wa...

Development of cost-effective amendments for treating dairy slurry has become a critical problem as the number of cows on farms continues to grow and the acreage available for manure spreading continues to shrink. To determine effectiveness and optimal rates of addition of either alum or zeolite to dairy slurry, we measured ammonia emissions and resulting chemical changes in the slurry in respo...

Introduction Manure odor is the result of the anaerobic decomposition of the organic matter present. By altering the composition of manure, as excreted, changes in the odor of decomposing manure may occur. Compositional alteration may occur by changing the dietary nutrient composition or by altering the use of these nutrients. Feed ingredients may contribute to manure odor due to their nutritio...

Anaerobic digestion of dairy manure with energy recovery through biogas combustion is generally viewed as a positive environmental approach to increase the use of renewable energy. However, there are potential negative impacts associated with emissions of methane and nitrogen species during digestion and after spreading of digester effluent that have the potential to counteract the environmenta...