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American Society of Agronomy
5585 Guilford Road • Madison, WI 53711-5801 • 608-273-8080 • Fax 608-273-2021
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Contact: Susan V. Fisk, Public Relations Director, 608-273-8091,

Hypoxia issues in the Gulf of Mexico

Nitrogen, phosphorus export into water must be reduced

October 24, 2013—The Mississippi River Basin is home to much of the United States’ fertile crop land. Though we need our food and energy crops, their production has led to an increase in the levels of nutrients such as nitrogen and phosphorus in our water sources. Increasing nutrient levels affects our rivers, lakes, and oceans. Single cell plants, called phytoplankton, feed off the increased nutrients, and in doing so start a cascade of events that leads to low oxygen levels in the water bodies. This low oxygen condition is called hypoxia. The result is dying fish and a poor ecosystem, called a “dead zone.”

The dead zone in the Gulf of Mexico, where the Mississippi meets the ocean, has received much attention in the last decade, and led to the creation of the Mississippi River/Gulf of Mexico Watershed Nutrient Task Force.

“We need to see an increase in the rate of implementing practices that lower nutrient export,” says Matt Helmers, PhD, of Iowa State University, and member of the Soil Science Society of America. “Cover crops not only decrease the amount of nitrogen and phosphorus leaving the fields, but they improve the soil in other ways. Subsurface drainage bioreactors—often called wood chip trenches—and specialized wetland systems also reduce nutrient export.”

Helmers admits the “challenges are more complex than changing the inputs to our crops,” such as corn and soybean. And, because there are not short-term financial gains to most of the practices that reduce nutrient export, the industry may be slower to adopt change. “If we don’t show reduced nitrogen and phosphorus export, we may see regulation.”

Helmers is part of the Iowa team working to develop and implement Iowa’s management plans. Currently, Mississippi, Iowa, Wisconsin, Indiana and Ohio, have plans in place. Seven states still need to finish their plans. He will be part of a panel discussion, “Hypoxia Issues in the Gulf of Mexico,” Wednesday, November 6, 2013: 12:00 PM. The presentation is part of the American Society of Agronomy, Crop Science Society of America, and the Soil Science Society of America Annual Meetings, Nov. 3-6 in Tampa, Florida. The theme of this year’s conference is “Water, Food, Energy, & Innovation for a Sustainable World” (


Media Invitation
Contact: Susan V. Fisk, 608-273-8091, Please RSVP by October 29, 2013 Members of the media receive complimentary registration to the joint meetings. If you would like a 1-on-1 interview with Dr. Helmer, contact Susan Fisk at the above email.

The American Society of Agronomy (ASA), is a scientific society helping its 8,000+ members advance the disciplines and practices of agronomy by supporting professional growth and science policy initiatives, and by providing quality, research-based publications and a variety of member services.