The Wisconsin Department of Natural Resources (DNR) is offering guidelines to help producers deal with the challenges associated with manure nutrient application during this summer’s drought.
Record hot and dry weather is causing deep, wide cracks to develop in many farm fields. Wisconsin agriculture and natural resource officials are urging farmers to inspect fields for such cracks and take precautions to reduce the risk of manure entering drain tiles and winding up in lakes, streams and groundwater.
“We want to alert farmers to the dangers that applying manure to fields with deep cracks poses,” says Andrew Craig, who leads DNR nutrient management efforts. “We encourage farmers to inspect their fields before applying manure and advise they either avoid spreading on such areas or take additional actions if they do spread manure.”
Recommendations include tilling cracked soil before applying manure and having an emergency response plan and supplies in place so they can respond quickly if problems occur.
“In past years, with similar cracking, manure that’s been applied to the surface or injected has flowed down these cracks and directly into tile drains and groundwater,” says Sara Walling, resource planning and water quality section chief of the Wisconsin Department of Agriculture, Trade and Consumer Protection.
In addition to potentially contaminating groundwater and surface water, farmers lose the nutrient value of the manure because it can move below the crop root zone. Farmers and nutrient applicators will need to take precautions with any liquid manure they apply to the land, regardless of solids content, says Kevin Erb, University of Wisconsin (UW) Extension conservation professional development and training coordinator. In a normal year, the risk is highest when manure solids content is less than 2.5%.
Fields that were not worked this spring, such as wheat fields or hayfields being top-dressed, need to be looked at very carefully before application, Erb says.
He recommends farmers take the following precautions when applying manure under the current dry conditions:
· Check fields for soil cracks and locate drain tile inlets and outlets before applying manure.
· Avoid applying manure to soil-cracked fields with or without drain tiles.
· When spreading can’t be avoided, work the soil with tillage equipment to fill in cracks and close off pathways. Have spill containment and response materials and equipment ready for quick use. Even if the manure is injected, fields should be pre-worked.
· Review your farm’s conservation plan before tilling fields.
During and after application:
· Apply manure in smaller, multiple low-volume applications on pre-tilled fields to help absorb manure.
· Monitor field drainage tile outlets for manure before, during and for several days after manure is applied to fields and after the next rainfall.
· Stop applying manure immediately if manure release from tile outlet is found, contain the spill and capture the drainage and land apply in an appropriate manner.
· Use tillage implements to work up the ground ahead of the spill or use absorptive materials.
· Notify Wisconsin DNR’s spill hotline: 1-800-943-0003. Immediate spill reporting is required by state law. DNR staff will provide spill response and help to contain the spill.
More information can be found on the Cooperative Extension System resource pages at http://www.extension.org/pages/27488/preferential-flow-of-manure-in-tile-drainage. A video showing steps to take before applying manure, and how to respond if an accident occurs, can be found on DNR’s YouTube “Farm News” playlist at http://www.youtube.com/playlist?list=PL2FD88C2442E6E2AF&feature=plcp.