Keeping yields, profits and water quality high

Over the period of 2003-2006, both synthetic Nitrogen fertilizer and herbicide use was lower in the three- and four-year LEI systems than in the two-year conventional system. Corn and soybean yields were as high or higher in the LEI systems as in the conventional system, and matched or exceeded average yields on commercial farms in Boone County. Further, lower herbicide inputs did not lead to increased weed problems. Without government subsidy payments, net returns were highest for the four-year LEI system, lowest for the three-year LEI system, and intermediate for the two-year conventional system. With subsidies, differences among systems in net returns were smaller, as subsidies favored the conventional system, but rank order of the systems was maintained.

“The results suggest that large reductions in agrichemical use can be compatible with high crop yields and profits,” says Dr. Matt Liebman, an agronomy professor at Iowa State University.

The project was supported by the USDA National Research Initiative (Biology of Weedy and Invasive Species Panel), and the Leopold Center for Sustainable Agriculture and the Department of Agronomy at Iowa State University. The project is continuing with additional investigations of energy use, soil quality, and weed population dynamics. Additional economic analyses will be conducted to determine the impacts of rapidly changing crop prices and input costs.

The full article is available for no charge for 30 days following the date of this summary. View the abstract at http://agron.scijournals.org/cgi/content/abstract/100/3/600.

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