From the Chicago Tribune:

Farmers are making significant cutbacks in erosion of soil and nutrients into the Great Lakes, where runoff is suspected of being a leading contributor to rampant growth of algae that damages water quality, a new U.S. Department of Agriculture report said.

The study estimated that because of changes in cultivation practices, the amount of sediments washing into rivers and streams that feed the lakes is 50 percent less than it would have been otherwise. Nitrogen and phosphorus runoff is about one-third lower than it would have been without the improvements. Read more.