Reducing Nitrate-N Losses to Achieve Water Quality Goals

Abstract

<p>Nutrient losses from agricultural systems in the Mississippi River basin have contributed to the hypoxic zone in the Gulf of Mexico. In 2008, in response to this challenge, the U.S. EPA‘s Hypoxia Task Force released an action plan for a national strategy to reduce, mitigate, and control hypoxia in the northern Gulf of Mexico and improve water quality in the Mississippi River basin (www.epa.gov/ms-htf). The action plan indicated that significant (i.e., 45%) reductions in riverine nitrogen and phosphorus loads are needed to achieve the goal of reducing the size of the hypoxic zone, and improve water quality in the basin. One of the main items in the 2008 action plan was the call for state-level nutrient reduction strategies. As a result, the twelve states bordering the Mississippi and Ohio Rivers have developed and begun implementing comprehensive nutrient reduction strategies (www.epa.gov/ms-htf/hypoxia-taskforce-nutrient-reduction-strategies). Iowa was one of the first states to conduct a scientific assessment of the potential nutrient reduction of different agricultural management practices and the level of implementation that might be needed to reach the goal of 45% reduction (www.nutrientstrategy.iastate.edu).</p>