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Victor Ananias
101 Soruda Organik Ürün Rehberi




Organic farming produces same corn and soybean yields as conventional farms
Kategoriler: Gıda ve Tarım, Ekolojik Tarım Yöntemleri
Tarih: 24-Ağustos-2005
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Organic farming produces the same yields of corn and soybeans as does conventional farming, but uses 30 percent less energy, less water and no pesticides, a review of a 22-year farming trial study concludes.

David Pimentel, a Cornell University professor of ecology and agriculture,
concludes, "Organic farming offers real advantages for such crops as corn and
soybeans." Pimentel is the lead author of a study that is published in the July
issue of Bioscience (Vol. 55:7) analyzing the environmental, energy and economic
costs and benefits of growing soybeans and corn organically versus
conventionally. The study is a review of the Rodale Institute Farming Systems
Trial, the longest running comparison of organic vs. conventional farming in the
United States.

"Organic farming approaches for these crops not only use an average of 30
percent less fossil energy but also conserve more water in the soil, induce less
erosion, maintain soil quality and conserve more biological resources than
conventional farming does," Pimentel added.

The study compared a conventional farm that used recommended fertilizer and
pesticide applications with an organic animal-based farm (where manure was
applied) and an organic legume-based farm (that used a three-year rotation of
hairy vetch/corn and rye/soybeans and wheat). The two organic systems received
no chemical fertilizers or pesticides.

Inter-institutional collaboration included Rodale Institute agronomists Paul
Hepperly and Rita Seidel, U.S. Department of Agriculture's Agricultural Research
Service research microbiologist David Douds Jr. and University of Maryland
agricultural economist James Hanson. The research compared soil fungi activity,
crop yields, energy efficiency, costs, organic matter changes over time,
nitrogen accumulation and nitrate leaching across organic and conventional
agricultural systems.

"First and foremost, we found that corn and soybean yields were the same across
the three systems," said Pimentel, who noted that although organic corn yields
were about one-third lower during the first four years of the study, over time
the organic systems produced higher yields, especially under drought conditions.
The reason was that wind and water erosion degraded the soil on the conventional
farm while the soil on the organic farms steadily improved in organic matter,
moisture, microbial activity and other soil quality indicators.

The fact that organic agriculture systems also absorb and retain significant
amounts of carbon in the soil has implications for global warming, Pimentel
said, pointing out that soil carbon in the organic systems increased by 15 to 28
percent, the equivalent of taking about 3,500 pounds of carbon dioxide per
hectare out of the air.

Among the study's other findings:

· In the drought years, 1988 to 1998, corn yields in the legume-based system
were 22 percent higher than yields in the conventional system.

· The soil nitrogen levels in the organic farming systems increased 8 to 15
percent. Nitrate leaching was about equivalent in the organic and conventional
farming systems.

· Organic farming reduced local and regional groundwater pollution by not
applying agricultural chemicals.

Pimentel noted that although cash crops cannot be grown as frequently over time
on organic farms because of the dependence on cultural practices to supply
nutrients and control pests and because labor costs average about 15 percent
higher in organic farming systems, the higher prices that organic foods command
in the marketplace still make the net economic return per acre either equal to
or higher than that of conventionally produced crops.

Organic farming can compete effectively in growing corn, soybeans, wheat, barley
and other grains, Pimentel said, but it might not be as favorable for growing
such crops as grapes, apples, cherries and potatoes, which have greater pest
problems.

The study was funded by the Rodale Institute and included a review of current
literature on organic and conventional agriculture comparisons. According to
Pimentel, dozens of scientific papers reporting on research from the Rodale
Institute Farming Systems Trial have been published in prestigious refereed
journals over the past 20 years.

Haber No: 870