Manure from Minnesota's farm animals are overloading rivers and lakes with nitrogen and phosphorus
A new Environmental Working Group investigation found that manure from Minnesota’s 23,000 animal feedlots raises nitrate and phosphorus levels in the state’s rivers, lakes and drinking water.
The EWG mapped where the 49 million tons of manure produced each year by the state are likely applied to cropland as fertilizer. According to the EWG, this is often on the same land where commercial fertilizer is also used.
“For the first time, we can clearly see the extent to which farmers are overloading land in Minnesota’s farm country with animal manure and fertilizer, and where the problem is the worst,” said Sarah Porter, senior GIS analyst with EWG and co-author of the report. “This new tool illuminates why water quality across the state is declining at an alarming rate.”
The Minnesota Pollution Control Agency estimates that 56% of all of the state’s surface bodies of water do not meet basic water quality standards and that non-point source pollution, like runoff from cropland and animal operations, is responsible for about 85% of water pollution. Many Minnesota animal operations are located in the and southeast parts of the state, which happen to have the worst nitrate contamination of groundwater as well, added MPCA.
EWG’s new investigation found that in 69 of 72 Minnesota agricultural counties, nitrogen from manure combined with nitrogen in fertilizer exceeded the recommendations of the MPCA and the University of Minnesota.
EWG found that on 57% of the fields likely to receive manure, phosphorus was applied in excess of what the crops actually needed. Even further, the growth and concentration of livestock operations is overwhelming the capacity of the land to handle the 49 million tons of manure that goes on surrounding fields every year. This ultimately threatens Minnesota’s lakes and streams and the quality of life of residents.