The past few growing seasons have challenged crop producers with just about every kind of weather problem. Yet U.S. yields have been amazingly strong. Many credit biotechnology with creating healthier, hardier plants.
Through its crop insurance program, USDA has demonstrated its belief that biotech seeds have less yield risk. Its Biotechnology Endorse-ment program reduces premiums for growers if at least 75% of acres in the unit are planted to qualifying corn hybrids. Introduced in four states in 2008 for corn hybrids from one company, the program was available in 12 states in 2010 for most traits, regardless of brand, resulting in a premium savings of more than $50 million.
The crop insurance loss ratio is one measure of crop production risk, and Iowa State University’s Center for Agricultural and Rural Development (CARD) found that ratio has been falling since biotech crops were introduced. From 1989 to 1999, the ratio was 1.12. From 2000 to 2008, it averaged 0.88 and has not exceeded 1.0 since 2003.
The economists adjusted for the fact that there are fewer and less severe droughts. "There have been enough droughts in certain regions of Illinois and Indiana to allow good measurements," says CARD economist Bruce Babcock.
They also concluded that protection against corn borers and rootworms is not the sole factor in better yields because soybean yield losses to drought have also declined.
Babcock concludes: "For corn, a return of a 1988 drought would reduce yields by 31% in 2008, far below the 45% losses from the same drought in 1988. This is a reduction in drought risk of 31%. For soybeans, estimated losses have been reduced from 28% of drought-free expected yields to 23%—a five percentage point improvement or a reduction in drought risk of about 18%."
Nature America Inc. offers analysis of 49 peer-reviewed reports of farmer surveys that compare yields and other economic indicators of those growing genetically modified (GM) varieties versus traditional varieties. The analysis reveals that of 168 results, 124 were positive, 31 showed no difference and 13 were negative for biotech. Furthermore, the yield improvements were greater in developing countries than in developed countries.
"Although today’s biotech seeds were not developed with drought tolerance as a goal, it appears that is just one of several unanticipated benefits," Babcock says. "It could be that these varieties allow earlier planting and are overall healthier or have better root systems, making them better able to deal with weather stress."
A CARD study of drought tolerance based on counties in Illinois, Indiana and Iowa found that corn yield loss under moderate drought was 20% since 2000, about half of what occurred during 1980 to 1989. "Soybean bushels per acre didn’t drop, but because of the better yield potential, the percentage did," Babcock says. (See the charts below.)
Drought in the Crosshairs. It is estimated that drought cost farmers $14 billion worldwide in 2009, and 85% of the U.S. corn crop is affected by water stress at some time during the growing season each year. Just four days of severe drought stress during the peak of summer can cut yields in half, according to James Borel, executive vice president of DuPont.
- September 2010