It will take big changes to current farming practices to reduce phosphorous runoff into Lake Erie.
According to a new study by the University of Michigan Water Center, stronger measures are needed to achieve the 40 percent drop from 2008 runoff levels agreed to last month by the U.S. and Canadian governments.
Phosphorous from farm fertilizers feed the kind of toxin-producing algae blooms that contaminated Toledo's drinking water in 2014 and caused a two day shut down of the city's tap water.
"There are ways to get to forty percent load reduction," said Don Scavia, lead author of the study and director of the Graham Sustainability Institute which overseas the Water Center. "But it's going to take an unprecedented amount of incentives to get agriculture to make it happen."
Scavia said that meeting the goal will require widespread use of strong fertilizer management practices, conversion of thousands of acres of cropland into grassland, and putting in stream-side vegetative buffers.
The Michigan Agri-Business Association challenged the UM study, stating that it relied on 15 year-old data and ignored fertilizer management improvements in use across Michigan.
This article was updated on March 24, 2016 to include a response from the Michigan Agri-Business Association.