Demonstration of Enhanced Technologies for Land Application of Animal Nutrient Sources in Sensitive Watersheds

Land application of animal manure has been implicated as a contributing factor of nonpoint source pollution. The application of these wastes are often made without adequate knowledge of its nutrient content, resulting in application rates far in excess of crop removal. In addition, application methods have lead to inefficient use of manure nutrients and potential pollution potential. Consequently, residual fertility has increased, and so have Nand P leaching from soil environments. Several pieces of legislation have been enacted to limit non-point source pollution including the Clean Water Act of 1972 (Public Law 92-500) and the Safe Drinking Water Act of 1974 (Public Law 93-523). The result of these legislative acts is that the USDA-NRCS has been tasked with carrying out training for, and implementation of nutrient management plans (NMPs). To develop a NMP, a manure sample must be collected and analyzed for total nitrogen (TN) and total phosphorus (TP) on an annual basis. The justification for requiring manure samples in NMPs is that published manure nutrient characteristics show significant variability as far as actual concentrations (Dou et aI., 2001; Lindley et aI., 1988). Because laboratory analysis of submitted manure samples can require up to two weeks, it has been suggested that on-farm methods for determining TN and TP would allow producers to rapidly assess nutrient concentration of nutrients in manure for calculating application rates. Although rapid methods exist for determining TN and TP (Cheschier, 1985; Van Kessel et aI., 1999), their use has not been widely adopted. A rapid on-farm method for determining TN and TP in swine slurry has been proposed by Higgins et al. (2004a,b), to provide producers with a means of predicting manure TN and TP to calculate application rates to meet crop and NRCS-