Ithaca, New York
July 13, 2005
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.
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