A new study from the U.S. Department of Agriculture shows that farmers using combinations of erosion-control and nutrient management practices on cultivated cropland have reduced losses of sediment, nitrogen, and phosphorus from farm fields, and decreased the movement of them to the Great Lakes and their associated waterways.
The Great Lakes Conservation Effects Assessment Project was prepared by the USDA's Natural Resources Conservation Service division. Dave White, Chief of the division, said the impetus for it was in the 2002 Farm Bill.
"Congress basically said to the USDA: 'Hey, you guys have put a lot of conservation on the ground. We want you to take a look at it and let us know if it's working. What have you accomplished? What more do you need to do?'" he said.
The report estimated that the use of conservation practices resulted in a 50 percent decline in sediment entering rivers and streams, a 36 percent decline in phosphorus and a 37 percent decline in nitrogen loading.
The USDA says this study, along with other studies along the Upper Mississippi River Basin and the Chesapeake Bay watershed, show the need for cropland to have higher conservation standards.
The study covered about 174,000 square miles — the entire U.S. side of the Great Lakes region. It's based on data gathered during a survey conducted by the USDA's National Agricultural Statistics Service from 2003 to 2006.
The USDA will be releasing 11 additional reports.