Posted: Friday, March 08, 2013 10:34 AM
By STEVE BROWN
Studies of various cropping systems show that the effects of drought are mitigated by organic practices, even when they are part of conventional management, researchers say.
"All farmers need to drought-proof their soils," said Jeff Moyer, director of farm operations at the Rodale Institute. "That is why the use of cover crops, which is an organic strategy, can be used even on conventional farms to improve their soil quality."
Ray Archuleta, soil agronomist at USDA's Natural Resources Conservation Service, said the practice of building more organic matter in the soil is also beneficial.
"Runoff is a symptom of poor soil function," he said. "The more you can capture that water, the better it is. That is what helps us get though the drought. Healthier soils will be more resilient against drought because they have more organic matter in them."
"Soil left undisturbed for several years becomes more tolerant to weather extremes," Rick Bednarek, the NRCS state soil scientist in Iowa, said. "The organic matter in undisturbed soil contains more moisture for plant use when rainfall totals are lower than normal. Conversely, healthy soil has the structure that allows excess water to infiltrate into the ground more easily."
Drought conditions continue in parts of the U.S. According to the U.S. Drought Monitor, the 2012 drought -- which it called the worst this country has seen in decades -- is becoming the 2013 drought. It reported that 54 percent of the continental U.S. remains in some stage of drought, compared with about 38 percent a year ago.
More than 20 years of data on different cropping systems were gathered near Arlington, Wis., some of the best cropland in the state, according to Erin Silva of the University of Wisconsin.
Reduced tillage benefited both conventional and organic systems, she said. Corn was especially resilient in extreme weather, with little change in yield during flood or drought years.
Trials at Rodale produced organic corn yields 31 percent higher than conventional in years of drought, 134 bushels per acres compared with 102.
"These drought yields are remarkable when compared to genetically engineered 'drought tolerant' varieties, which saw increases of only 6.7 to 13.3 percent over conventional (non-drought resistant) varieties," Rodale reported. "We incorporated the GM crops to reflect current American agriculture, rather than to specifically study their performance."