Melt brings manure runoff warning
Warm temperatures mean shrinking snowbanks across the region, but the rapid melting brings the threat of manure runoff into nearby waters, the Minnesota Pollution Control Agency said.
The MPCA is calling on farmers who spread livestock manure on cropland during winter months to take steps to ensure it doesn’t flow into ditches and streams — which could add phosphorus and nitrogen to already nutrient-polluted waters.
“Producers should consider short-term stockpiling of manure in the field until after the major snowmelt of the year,” Wayne Cords, a supervisor with the MPCA’s feedlot program, said in a news release. “While this does involve additional time and labor, there are significant benefits in the reduced pollution potential, as one well-placed short-term stockpile poses significantly less pollution hazard than a whole field of surface-applied manure.”
If stockpiling is not an option, the MPCA says to limit manure spreading to the flattest parts of a field. The slope should be less than 6 percent for solid manure and 2 percent for liquid manure.
State guidelines require manure spread on frozen or snow-covered soil be kept 300 feet away from surface water and open title intakes, the MPCA says.
“If manure is being applied within waterways or near streams, there is a twofold negative effect,” said Beau Kennedy, water planner with the Goodhue County Soil and Water Conservation District. Not only does the runoff contribute to nutrient pollution in Minnesota waters, but the loss of nutrients on fields means farmers will have to resort to purchasing commercial fertilizer to compensate.
And, because of the karst topography in northern- and eastern-Goodhue County, contaminated surface water can easily flow into area groundwater, affecting drinking water and trout streams, Kenney added.
Excess nutrients in rivers and streams promote the growth of algae, which can reduce oxygen levels and lead to fish kills, according to the MPCA. The nutrients also can flow into the Great Lakes and the Gulf of Mexico.
Farms that experience manure runoff into water must report the incident to the Minnesota Duty Officer by calling 800-422-0798, “and take immediate action to reduce environmental impact,” according to the MPCA. Temporary fixes include putting up beams to stop the runoff, plugging culverts and drain tile intakes and soaking up liquids with hay, straw and other absorbent materials.