Creating Opportunities for In-Season Manure Applications Using Cover Crops and Alternative Forages
2022
- Nutrient and Pest Management Program, UW Madison
Project Media
Dairy manure is a valuable nutrient source for row crop production but requires judicious management to reduce potential application risks to ground and surface water quality. The first-year nutrient “book values” of liquid dairy manure (< 4% dry matter, < 1 hour to incorporated or injected) is estimated at 7 pounds of nitrogen (N), 3 pounds of P2O5, and 11 pounds K2O per 1,000 gallons (Laboski and Peters, 2012). Therefore, manure applications followed by potential nutrient runoff and/or leaching events can pose water quality risks. According to the Wisconsin Water Quality Report to Congress (WDNR, 2020), 13% of Wisconsin’s evaluated surface water bodies are classified as impaired, with phosphorus as the most frequently cited pollutant. In terms of groundwater, nitrate is the state’s most widespread contaminant, with approximately 10% of private drinking water wells exceeding the safe drinking water standard (WDNR, 2021). It is estimated 90% of Wisconsin’s groundwater nitrate enrichment results from agricultural input use, including manure and fertilizer applications (WDNR, 2021).