Is corn boom expanding Gulf of Mexico’s ‘dead zone’?By Conrad Wilson
Star Tribune, June 2 2008
Some fear an ethanol-fueled harvest in the Midwest may be behind the hard times for marine life at the other end of the Mississippi River.
WASHINGTON – Last fall, the farm fields of the Midwest yielded record profits and the greatest corn crop in recent history. But there may have been an unintended consequence hundreds of miles to the south: As the corn grew, so did the size of the "dead zone" in the Gulf of Mexico.
The dead zone is a low-oxygen area virtually uninhabitable by marine life. It emerges in the spring and summer, created in large part by high nitrogen levels and other nutrients such as phosphorus. Its size varies: Last year it was about as big as Massachusetts.
Recent studies suggest that a prime driver for the dead zone — or hypoxia — is farm-field runoff from the Mississippi River basin, although cities also play a role, contributing municipal, industrial and lawn and garden runoff.
Now, with the growing season underway, Congress late last month passed a major five-year farm bill over President Bush’s veto. It includes an increase in funds for conservation, which could keep some additional land out of production and rein in some runoff. Market conditions, however, appear to favor production.
Fueled in part by the growing ethanol industry, more corn was planted in the United States last year — 94 million acres, including 8.4 million in Minnesota — than in any year since 1944. While projections indicate those totals will be down this year, they will still be substantial. More soybeans and wheat also will be planted, although they require fewer nutrients.
"The ethanol boom is accelerating an already ongoing nitrogen problem from corn production," said Michelle Perez, senior analyst with the Environmental Working Group, an environmental and public health organization based in Washington.
Eugene Turner, a professor of coastal ecology and oceanography at Louisiana State University, says his research has shown that soil in the Mississippi Delta area accumulates carbon from year to year, which decreases oxygen in the Gulf and ultimately translates into a larger hypoxic zone.
Although Turner has said that he can’t yet scientifically prove that the ethanol boom is causing the growing hypoxic zone, his research points in that direction. The zone’s increase in size in recent years corresponds with the increase in corn planting and ethanol production, he said.
Last fall, Turner said, he measured the highest nitrate concentrations in the Gulf in 13 years. "Every year we don’t do something about lowering the hypoxic levels … we have a larger hypoxic zone," he said. "There are more corn acres planted and more nitrates coming down."
Data from the Fertilizer Institute, a trade association based in Washington, indicate that fertilizer use declined, both nationally and in Minnesota, between fiscal years 2004 and 2006 (ending in June 2006). Numbers for the year ending in June 2007 are not yet available, but the institute expects to show that there was a 7 to 8 percent increase nationally.
"Demand was flat until the ethanol boom kicked in," said Estelle Grasset, public affairs specialist at the institute. Internationally, fertilizer use has risen as well, largely because of the need to feed a growing world population, Grasset said.
Farm interests weigh in
Farm interests acknowledge that agriculture contributes to runoff, but they say it is far from the only source.
Kevin Paap, a corn and soybean farmer and president of the Minnesota Farm Bureau, said there are a number of possible reasons for the dead zone. "One of the things that we want to make sure that we take into consideration is not only the human sources, which can be nutrients as field runoff," he said. "But we also have natural sources for that."
Additionally, Paap said, "The confusing thing to me as a farmer is we’ve seen a reduced nutrient use in recent years, but we’ve seen a hypoxic zone increase. If I’m using less