Study finds organic yields trail conventional farming methods

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A sign along organic fields in Minnesota warning that no chemical weed killers should be sprayed near there. A new study finds that on average, organic farms produce fewer bushels of grain, vegetables and fruit per acre than farms that use chemical pesticides and fertilizers.
MPR Photo/Mark Steil

A new study published today in Nature, the international weekly journal of science, concludes that organic farming methods produce less food per acre than conventional practices.

The study, done with help from a Minnesota researcher, covered a wide variety of organic agricultural production, from large Midwest farms to small operations in developing countries. But despite the geographical variation the basic findings were always the same.

On average organic farms produce fewer bushels of grain, vegetables and fruit per acre than farms that use chemical pesticides and fertilizers, said study co-author Jonathan Foley, director of the Institute on the Environment at University of Minnesota.

"The conventional farms just have more tools in their arsenal," Foley said. "And they have a much higher yield than their counterparts in the organic world. Often as high as 40-percent difference."

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The study notes that while organic production has environmental benefits, it may fall short in producing the yields needed for a growing world population. It concludes that the planet may benefit from a system that blends the best of the organic and conventional farming models.

Foley said organic farmers should consider using commercial fertilizers, instead of relying solely on animal manure and decomposing vegetation to provide plants with nitrogen. He said the organic method is less efficient in providing that critical nutrient.

"Adding a small, targeted, only if necessary, input of chemical fertilizer at the right time in small doses would help the plant grow a little bit more," Foley said.

But using such industrial fertilizers is forbidden in the organic farming world. To label their grains and other crops 'organic', they must follow organic farming conventions, which include the chemical fertilizer ban.

Minnesota organic farmer Carmen Fernholz, who farms 500 acres near Madison, said the fertilizer recommendation is short-sighted. He said the chemical yield boost could destroy the beneficial microbial life found in organic soils.

For Fernholz, there's a better way to boost organic yields.

"We have to ratchet up the research," he said.

For years, Fernholz said, government research dollars have largely benefitted conventional agriculture. He said organic farming should receive the same amount of research and development funding.

Fernholz said in some years he can match conventional yields. More research could help organic farmers fine-tune their systems, so that those high yields become normal, he said.