Farming strides toward sustainability

Science Now: …[F]armers and environmentalists haven't been on the best of terms. "There hasn't been a lot of understanding between the two," says Kenneth Cassman of the University of Nebraska, Lincoln. "People in agriculture have felt persecuted for producing for the safest, cheapest food in the history of mankind." Meanwhile, some green groups are deeply suspicious of large agribusiness and its high-tech tools, including genetically modified crops. Last year, for example, an ambitious effort designed to assess the role of science in agriculture and development was derailed by disputes….

That's why Cassman and others are heartened by the development of the consortium that produced the report, run by the nonprofit The Keystone Center in Keystone, Colorado. "To have a scientific, credible conversation between agribusiness and the environmental community is really great," says Jonathan Foley, a global change scientist at the University of Minnesota, St. Paul, who studies the impact of agriculture. "This is a watershed moment."

The report analyzes the impact of growing four crops--corn, soy, wheat, and cotton, which account for 70% of farmed acres in the Unites States--from 1987 to 2007. One key finding is that the amount of land required to grow a certain amount of food has fallen.

…The analysis, led by agronomist Stewart Ramsey of the consulting firm Global Insight, also finds that the amount of energy spent on farming has fallen by 40% to 60%, probably because farmers who plant genetically modified crops are driving tractors less frequently to spray pesticides and herbicides. Irrigated water use dropped by 20% to 50%, the report found, and carbon emissions fell by about 30%. Wheat was the only crop of the four surveyed that did not post big gains in efficiency. More water is being used, and an increase in application of nitrogen fertilizers has meant an increase in energy use and climate impacts per bushel.

…Tom Tomich of the University of California, Davis, notes that the increases in efficiency per unit output, however, do not necessarily mean improvements in sustainability. The overall picture matters: Despite the improved efficiency of corn production, it still requires more energy and fertilizer than soybeans do. So when farmers plant corn instead of soybean--as they have since the expansion of biofuel demand--the overall environmental impact increases. "We're very far away from a truly sustainable agriculture," Foley says....

Constable's "The Cornfield," 1826