In 2015 Ohio, Michigan and the Canadian province of Ontario pledged to seek a 40 percent reduction in phosphorous runoff into Lake Erie within a decade. Now a study by the University of Michigan Water Center shows reducing runoff enough to prevent algae blooms will require changes on the region's farms. Jim Letizia reports.
The study says current efforts are falling short of what's needed to achieve a 40 percent drop in runoff, a target agreed to by the U.S. and Canada in February. Excessive levels of the nutrient are the leading cause of algae blooms, which in 2014 left more than 400 thousand people in Toledo and southeastern Michigan without tap water for two days because algae toxins were found in the water supply. Another bloom last year was the largest on record. Phosphorus also causes a “dead zone” in Lake Erie’s central basin. Using computer modeling, a team of scientists tested different combinations of best-management practices that could bring the algae under control. Some are already in use, such as planting vegetation buffers between cultivated fields and waterways. Others include applying phosphorus-based fertilizers beneath the land’s surface instead of on top, where it’s more likely to wash away, and planting cover crops such as winter wheat.The report says too few farmers are using voluntary practices to stop runoff and stronger measures are needed, such as converting thousands of acres of cropland into grassland. The Ohio Farm Bureau Federation says that could put some growers out of business. The federation criticized the study for focusing only on agriculture instead of other phosphorus sources such as sewage treatment plants.
