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Public Radio's Environmental News Magazine (follow us on Google News)

What's Corn Got To Do With It?

Air Date: Week of

In this thermal resonance image, the red colored areas show abnormally large summer blooms of phytoplankton due to high levels of nitrogen run-off in the Gulf. (Courtesy of NOAA)

Fertilizer runoff from farms in the Corn Belt is contributing to a growing marine dead zone in the Gulf of Mexico. Host Steve Curwood talks with scientist Don Scavia of the University of Michigan. Professor Scavia thinks he knows how to stop the dead zone...with a little help from the 2007 Farm Bill.


GELLERMAN: It’s peak growing season in the Midwest corn belt, where they say it’s a good year if stalks are knee high by the fourth of July, but what helps crops grow in the Midwest runs down into the Gulf of Mexico. And that means trouble. Millions of tons of fertilizer used on farms throughout the vast Mississippi watershed run downriver into the gulf, creating a huge dead zone where most marine life can’t survive.

It’s been expanding for decades, but some marine scientists think this year’s farm bill, which Congress is now getting ready to debate, might help bring the dead zone back to life.

Living on Earth’s Steve Curwood recently spoke with Don Scavia. He’s a Professor of Natural Resources and Environment at the University of Michigan, and one of the editors of a new book called “From the Corn Belt to the Gulf.”

CURWOOD: Explain basically, what happens to create a dead zone?

SCAVIA: Well, it’s generally caused by an excess amount of nutrients going into the ocean, or into the Great Lakes. Those nutrients cause algae to grow beyond what the ecosystem can accommodate. The algae will sink to the bottom and decompose and that process of decomposition uses up the oxygen. If that concentration of oxygen gets below the level to sustain fish and organisms that we really care about, we call it a dead zone.

CURWOOD: So, connect the dots here for us, Don. Explain how the run off of nutrients from farms hundreds of miles up the Mississippi get out into the Gulf of Mexico and cause all this.

SCAVIA: Well, agriculture, particularly corn agriculture, is very leaky. You put fertilizer on the ground, a lot of the nitrogen in that fertilizer will get very quickly into the ground water, into the small streams, to the large streams, to the rivers, eventually to the Mississippi River and down into the Gulf. And it’s quite amazing how quickly that water moves from the farm field to the Gulf.

CURWOOD: Now, this isn’t the only dead zone in the world or in America, right?

SCAVIA: That’s right, there are dead zones caused by the same sort of process around the world. The Baltic Sea is probably the largest one. The Gulf of Mexico is the second largest in the world. But in the United States, half of our bays and estuaries have the same sort of problem. Even Lake Erie. The dead zone in Lake Erie that we thought we had solved decades ago has returned. So it’s a problem around the country.

In this thermal resonance image, the red colored areas show abnormally large summer blooms of phytoplankton due to high levels of nitrogen run-off in the Gulf. (Courtesy of NOAA)

CURWOOD: Now, why is there so much attention to the Gulf dead zone?

SCAVIA: The attention there has come from a recent law that was passed to actually do an analysis and develop an action plan for it. And a lot of that was driven by the concern that the fisheries, particularly the shrimp fishery which could be somewhere between half and three quarters of a billion dollar-a-year fishery, may be at risk if this dead zone continues or in fact may grow in the future.

CURWOOD: So, how can farmers grow the food we need without adding to this problem downstream?

SCAVIA: Farmers can grow their crops in ways that are beneficial to the environment. If we were to put in and actually subsidize farmers to put in buffer strips between their crops and the streams, to encourage the construction of wetlands, to incentivise farmers to use only the amount of fertilizer they need and no more, to do precision farming. There are a number of ways to actually keep the nitrogen on the land. And once it gets into the water, to actually remove it from the water before it gets into the Gulf. And all we really do need in order for that to happen is for the farm bill to put funds into those kinds of conservation measures to help enable the farmers to do that.

CURWOOD: Now, there’s a lot of buzz about farm-based fuels, particularly ethanol. A lot of folks are growing corn in response to the demand for ethanol. How does this problem figure into that, and how do you think the farm bill could make things better under such a scenario?

SCAVIA: Well, there’s no question that growing more corn to supply the ethanol demand, not only increases the price of corn but it’s going to increase the amount of nitrogen getting into the Gulf of Mexico and most likely increase the size of the dead zone. So, that’s going to happen unless there are incentives in the farm bill to move away from corn-based ethanol and into cellulosic ethanol.

CURWOOD: Cellulosic ethanol doesn’t really exist yet, I mean the inventions aren’t quite together. The technology doesn’t quite work yet.

SCAVIA: That’s right and I think hopefully the farm bill could provide research funding in technology and development, and even infrastructure development to look at not just switch grass but wood products and others to get there. We know how to do corn-based ethanol. We don’t know quite how to do the cellulosic yet, but that is really what we need to move towards if we’re going to be concerned about the environment.

CURWOOD: Don Scavia you’ve been working on this for what, the last 30 years?

SCAVIA: That’s right.

CURWOOD: So, from your perspective what now do you think are the prospects for change?

SCAVIA: I think the prospects might actually be better in this farm bill than in the past. I’m hoping that the environmental dimensions to the problem have become more acute and more obvious to those who are developing that policy. There are also international trade dimensions to it. The Europeans and others are not particularly pleased with U.S. subsidies, the way they’re done now. They’re trying to push more to subsidize conservation as opposed to production. So, I think there are pressures and dimensions in new ways that haven’t been there before that gives me some hope that this farm bill might be the way forward for us.

I’m always optimistic. I always think that we can do it. When we dealt with a very similar kind of problem in the small lakes and rivers in the ’60s and ’70s, there was enough motivation and willpower and funding to solve that problem. We’re just working on a larger scale now and it takes longer.

CURWOOD: Thank you so much, sir.

SCAVIA: You’re very welcome.

[MUSIC: Charlie Haden & Hank Jones “Wade In The Water” from ‘Steal Away’ (UMG Recordings – 1994)]

GELLERMAN: Don Scavia is one of the editors of the new book “From the Corn Belt to the Gulf.” He spoke with Living on Earth’s Steve Curwood.



NASA Dead Zone site

Resources for the Future Report on Dead Zones


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