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17 April 2014 12:48 pm ,
Vol. 344 ,
Officials last week revealed that the U.S. contribution to ITER could cost $3.9 billion by 2034—roughly four times the...
An experimental hepatitis B drug that looked safe in animal trials tragically killed five of 15 patients in 1993. Now,...
Using the two high-quality genomes that exist for Neandertals and Denisovans, researchers find clues to gene activity...
A new report from the Intergovernmental Panel on Climate Change (IPCC) concludes that humanity has done little to slow...
Astronomers have discovered an Earth-sized planet in the habitable zone of a red dwarf—a star cooler than the sun—500...
Three years ago, Jennifer Francis of Rutgers University proposed that a warming Arctic was altering the behavior of the...
- 17 April 2014 12:48 pm , Vol. 344 , #6181
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Organic Farms Reap Many Benefits
30 May 2002 (All day)
Organic farmers have long touted their methods as a more eco-friendly way to nourish the world's population. But few rigorous studies have looked at the long-term costs and yields of organic farming. Now the longest and most comprehensive study to date comparing organic and conventional farming brings encouraging news for organic fans: Organic farms can be nearly as productive as regular farms for some crops, and they leave soils healthier.
A team led by agronomists Paul Mäder of the Research Institute of Organic Agriculture in Frick, Switzerland, and David Dubois of the Swiss Federal Research Station for Agroecology and Agriculture in Zürich began the 1.5-hectare trial in 1978 near Basel, Switzerland. The experiment included one group of plots that mimicked conventional farms: These were treated with chemical pesticides and herbicides and soluble nitrogen for fertilizer. For the organic plots, the team used only manure and mechanical weeding, along with plant extracts to control pests.
Over 2 decades, the average crop yield was about 20% lower in the organic plots, the team reports in the 31 May issue of Science. The best-performing organic crop was winter wheat, which yielded just 10% less than the conventional harvest. Potatoes fared the worst with about 38% lower yields. The yields are impressive given that the organic plants received less than half the nutrients given to conventional plots, says John Reganold of Washington State University, Pullman. "To add that much less fertilizer and still get 80% of the conventional yields is outstanding."
Because no synthetic fertilizer had to be produced or applied, growing organic crops also required less energy than conventional crops--up to 56% less energy per unit yield. The team also found evidence that nutrient-cycling microbes are more plentiful and efficient in organic soil, making a greater percentage of nutrients available to plants. Soils also appeared to be healthier in organic plots, with 40% more roots colonized by fungi that assist with plant nutrition. Earthworms were up to three times more abundant, and there were twice as many spiders and other pest-eating arthropods.
"This study is as complete a picture as we have from anywhere," says Phil Robertson, an agricultural ecologist at Michigan State University, East Lansing. Reganold concurs: "This gives more credibility to organic systems."
Research Institute of Organic Agriculture
Swiss Federal Research Station for Agroecology and Agriculture
USDA National Organic Program
General info on organic farming from the Organic Alliance