Right practice, right place: A conservation planning toolbox for meeting water quality goals in the Corn Belt

O n August 2, 2014, the residents of Toledo, Ohio, were warned that their drinking water was potentially contaminated with microcystin, an algal-related toxin that can cause various illnesses and liver damage, and unsafe to drink (Bullerjahn et al. 2016). They were the latest victims of a series of water quality crises in the United States, many (including the Toledo event) attributable in large part to nutrients lost from agricultural landscapes. Meanwhile, hypoxia in the Gulf of Mexico continues unabated (USEPA 2015), with the 2017 dead zone being the largest recorded (NOAA 2017). In response to these crises, states in the Mississippi River and Great Lakes drainage basins are undertaking ambitious efforts to achieve 40% to 45% reductions in nutrient losses from agriculture. There is a growing consensus that in-field conservation practices, such as improved nutrient management, conservation tillage, and cover crops, will not, singly or together, achieve the 45% nutrient reduction goals (Schilling and Wolter 2009; Iowa Nutrient Reduction Strategy 2013). Meeting these water quality goals will require combining in-field nutrient management practices with downstream nutrient removal practices, such as bioreactors and filter strips at the edges of fields and wetland creation and floodplain restoration below fields (McLellan et al.