|Sustainable Systems » Ecological Agriculture & Food Security
|Title: Organic farming produces same yields but uses less energy and no pesticides
Source: Cornell University
Publication date: July 13, 2005
Posting date: August 03, 2005
Organic farming produces same corn and soybean yields as conventional farms,
but consumes less energy and no pesticides, study finds
Susan S. Lang
Cornell University, July 13, 2005 [via agnet]
ITHACA, N.Y. -- 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
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.