Organic methods outpace conventional in long–term research

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 AMES, Iowa -- After nine years of comparison, the clear differences between organic and conventional crop production systems are emerging: the longer rotations and careful management of the organic system show greater yields, increased profitability, and steadily improved soil quality over conventional practices.

Those are the conclusions drawn from experimental plots set up at the Iowa State University Neely-Kinyon Research Farm near Greenfield. The plots are part of the Long-Term Agro-ecological Research (LTAR) initiative led by Kathleen Delate of the ISU agronomy and horticulture departments and supported by the Leopold Center for Sustainable Agriculture since 1997. The study is believed to be the largest randomized, replicated comparison of organic and conventional crops in the nation.

Delate is now finishing her tenth year of organic production at the farm, and has nine years of comparative data from the combined crop trials.

"We set up the experiment in 1998 to examine suitable crop rotations that would provide high yields, grain quality and adequate soil fertility during the three-year transition to organic and following certification," she explained.

"We replicated conventional and organic systems, using identical crop varieties, and found that organic crop yields were equal to conventional acres in the three years of transition. In the fourth year, organic corn yields in the longest rotation outpaced those of conventional corn. Organic and conventional soybean yields have been similar every year of the trial."

But the biggest differences are in soil and water quality. Delate said the organic plots infiltrate more water, which reduces soil runoff and more effectively recharges groundwater supplies. The organic soils also cycle nutrients more efficiently, making them available when and where the plants need them. Soil structural stability also remained good, despite increased tillage involved with the organic rotations.

Delate will discuss her research at the 7th Annual Iowa Organic Conference November 19 in Ames. The conference also includes sessions on organic livestock production, weed management, direct marketing and opportunities for selling organic crops, and ways of producing fruit and vegetable crops in an organic system.

For more information about the ISU Organic Agriculture program, go to: http://extension.agron.iastate.edu/organicag/ or call (515) 294-5116.

Through its research and education programs in the areas of policy, marketing and ecology, the Leopold Center supports development of profitable farming systems that conserve natural resources. The Center was established by the 1987 Iowa Groundwater Protection Act.

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The Leopold Center was established by the 1987 Iowa Groundwater Protection Act as a research and education center at Iowa State University to develop sustainable agricultural practices that are both profitable and conserve natural resources. Iowa State does not discriminate on the basis of race, color, age, religion, national origin, sexual orientation, sex, marital status, disability, or status as a U.S. Vietnam Era Veteran. Any persons having inquiries concerning this may contact the Director of Affirmative Action, 3210 Beardshear Hall, (515) 294-7612.

This page was found at http://www.leopold.iastate.edu/news/11-13-2007/organic-methods-outpace-conventional-long-term-research on 01/21/2013