Updating manure values in SNAPplus for better nutrient management planning

PI: Joel Peterson


Peterson is professor and chair of agricultural engineering technology at UW–River Falls. He has industry experience with private engineering consulting firms as well as the U.S. Army Corps of Engineers and the Minnesota Board of Water and Soil Resources.

SnapPlus is a nutrient management planning software that allows farmers, planners, and others to estimate soil and nutrient runoff losses on a field-by-field basis and is a key tool to help decision makers protect soil and water quality. Excreted manure nutrient values from laboratory testing may be used as input to the program, if available. In the absence of laboratory results, default values, derived from laboratory analyses conducted in 2012 across Wisconsin, are used for manure nutrient values in confined housing where the manure is recoverable. Increases in dairy productivity and diet have led to changes in manure nutrient excretion values. This project will update the manure nutrient values for indoor housed and grazing animals, compare them to regression and mass-based volume and nutrient excretion values contained in ASABE standard D384 and recommend changes if necessary. Finally, researchers will implement any recommended changes and evaluate the impact of those changes in a case study. Laura Ward Good from the Department of Soil Science at UW–Madison is collaborating on this project.