By KEVIN WALKER
Michigan Correspondent

EAST LANSING, Mich. — A recently published study suggests the increase in corn acreage used for ethanol production produces environmental and, in some cases, economic disadvantages.

The study, called Increasing Corn for Biofuel Production Reduces Biocontrol Services in Agricultural Landscapes, was published Dec. 15 in the online “Proceedings of the National Academy of Sciences.” The lead authors of the study are professors at Michigan State University and are also affiliated with the Michigan Agricultural Experiment Station (MAES).

Douglas Landis and Scott Swinton are also affiliated with the Great Lakes Bioenergy Research Center, a partnership between MSU and the University of Madison-Wisconsin. The partnership, which is funded by the U.S. Department of Energy, is doing research to help solve problems related to cellulosic ethanol production.

“I’m involved in biofuels research and I think it’s a really important area,” Swinton said. “I just don’t think we should have all our eggs in one basket. The article isn’t meant to be a diss to ethanol in general.”

The thrust of the study is that the increase in corn acreage, much of which is used for ethanol production, is hurting the soybean crop by reducing the suppression of the soybean aphid by lessening its natural predators in areas where soybeans are grown.

“The soybean aphid is an invasive insect pest that has become the most significant threat to soybean production in the United States.
Soybean aphid is consumed by a diversity of natural enemies, including predators and parasitoids, that can provide strong top-down regulation of its populations, resulting in increased crop yields,” the article states.

According to the authors, what has happened in the four states studied – Iowa, Michigan, Minnesota and Wisconsin – is that the increase in the corn harvest has been primarily at the expense of soybeans.

Farmers who grow corn also tend to grow soybeans and vice versa.
In 2007 harvested corn acreage increased by 20 percent in Michigan; there was a corresponding 13 percent decline in soybeans harvested that year. There were similar corresponding relationships in the other states under study.

“We found that (soybean aphid suppression) declined significantly with increasing proportion of corn in the landscape ... but (this) was not significantly related to the proportion of soybean,” the article states.

“Thus, exchanging corn for soybeans does not have a neutral effect on biocontrol services.

Rather, as corn area increased in the local landscape, biological control services to soybean decline.”

Although the loss of soybean aphid suppression cost producers a certain amount of money, in the separate interview Swinton acknowledged this cost was more than offset by the gain producers derived from growing more corn at a time when this commodity was selling at a high price.

According to the authors, “development of cellulosic ethanol-processing capabilities that can use a variety of feedstocks such as switchgrass, mixed prairie and woody biomass create the potential to diversify agricultural landscapes and support multiple ecosystem services.

For example, production of switchgrass, a native perennial grass, can increase wildlife habitat while reducing fertilizer use, water use and soil erosion.”

But Swinton said not to read too much into the study. “This report is not one that’s making policy recommendations, but it’s good information for growers,” he said. “This is a very narrowly focused study.”

The other study researchers are Mary Gardiner of MSU and Wopke van der Werf of Wageningen University in The Netherlands. Text of the study can be found free of charge online at www.pnas.
org/content/105/51/20552.full.pdf