New website helps farmers pick safe times to spread manure

CALS staffers in two departments helped create a new web-based tool that helps farmers decide when conditions are right to spread manure on their land, so it stays on the fields to fertilize the soil instead of risking pollution of streams and groundwater. John Panuska in the Department of Biological Systems Engineering and Laura Good and Rick Wayne in the Department of Soil Science were among experts from a number of state and federal agencies who developed the web-based Wisconsin Manure Management Advisory System, which was launched on June 14.

Good and Panuska contributed their knowledge of hydrology and runoff modeling to help determine the thresholds for low, medium and high risk of manure runoff. Wayne did the programming and built the website, which is hosted in the soils department.

The system is comprised of two mapping tools that help farmers manage both the long- and short-term risk of manure runoff. One tool, nutrient application restriction maps, will help farmers manage long-term runoff risk. The maps show appropriate areas and seasons for applying manure and fertilizers, based on over 30 years of weather history. This helps avoid long-term phosphorus build-up in soils, reduces the chances of nitrogen leaching into groundwater, and cuts the risk of winter spreading on fields where it should be avoided. The second tool, called the runoff risk advisory forecast, helps farmers during the few times each year when runoff risk is high and they need “just-in-time” planning to avoid it. These maps are updated twice daily to show what parts of the state are at high risk for runoff in the next three days, based on rainfall, snowmelt, soil moisture, temperatures and weather forecasts.  In the winter, they will show whether soils are frozen or snow-covered, or snow is melting.
Both tools are available at

“We’ve been developing these systems over several years as part of our efforts to better manage animal waste and fertilizer applications,” said Jim VandenBrook, water quality section chief for the Wisconsin Department of Agriculture, Trade and Consumer Protection.

“We’ve drawn on the expertise of a lot of state and federal partners to come up with a practical system. Crop consultants and nutrient management planners have already been using the nutrient application restriction maps, as have farmers. With the addition of the new runoff risk advisory forecast, farmers don’t have to guess how risky it is to spread manure.”

Other agencies involved in creating the mapping website include the Wisconsin Department of Agriculture, Trade and Consumer Protection; Wisconsin Department of Natural Resources; National Oceanic and Atmospheric Administration-National Weather Service River Forecasting Center; U.S. Department of Agriculture-Natural Resources Conservation Service; Discovery Farms; UW-Platteville and its Pioneer Farm; and U.S. Geological Survey.