Yield is lower in organic farming, but so is cost of production, study shows
Subject: Yield is lower in organic farming, but so is cost of production,
study shows
Date:
Fri, 31 May 2002 10:19:01 -0400
From: Stephen Tvedten <steve@getipm.com>
Organization: Get Set Inc. (www.getipm.com)
To: Paul Helliker <phelliker@cdpr.ca.gov>
Director, State of California, Department of Pesticide
Regulation
cc: Christine Whitman whitman.christine@epa.gov
5/30/02 9:31 PM - The Associated PressYield is lower in organic farming, but so is cost of production, study shows
WASHINGTON (AP) -- Crop yields on organic farms averaged about 20 percent less than those on conventional farms, but the production used about 50 percent less energy and built healthier soils, a study found.
In a 21-year comparison between organic and conventional farming in Switzerland, researchers said the fields of the organic farms had better balances of nutrients, soil bacteria, earthworms and plant pest predators than did the other farms, all signs of healthy fields.
Organic farms use no synthetic fertilizers or pesticides. In the comparison study, the organic and conventional farms had the same tillage, crop rotation and crop varieties. Both types of farms grew potatoes, barley, winter wheat, beets and grass cover.
Winter wheat production on organic fields was about 90 percent that of conventional farms. Yields of cereal crops overall generally were 60 percent to 70 percent that of conventional farms, while potato yields were 58 percent to 66 percent.
The researchers attributed the sharper reduction in potato yields on organic farms to a low potassium supply and to an infestation of insect pests. Conventional farms control for such problems with fertilizers and pesticides.
A detailed comparison of the soils showed that the organic fields had more biological activity and biomass, both signs of soil health, than did the conventional fields.
"Biomass and abundance of earthworms were higher by a factor of 1.3 to 3.2 in the organic plots as compared with conventional," the authors reported.
The organic plots also had a much higher level of bacteria and fungi which help process soil nutrients and aid in their absorption by the roots of plants.
Organic fields also had a higher ratio of spiders and beetles that feed on plant pests. In conventional farming, chemicals designed to kill pests also can kill beneficial insects.
The study, being published Friday in the journal Science, was conducted by researchers at the Research Institute of Organic Agriculture in Frick, Switzerland, and at the Swiss Federal Research Station for Agroecology and Agriculture in Zurich.
On the Net: Science Magazine:
http://www.sciencemag.org
Copyright 2002 Associated Press. All rights reserved.
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