The Environmental Risks Of Corn Production Growing corn uses a lot of water and fertilizer. We look at what farmers and companies that buy corn can do.
NPR logo The Environmental Risks Of Corn Production

JEREMY HOBSON, HOST:

This is HERE AND NOW. And a report out today has a worrying forecast for the nation's corn crops, which account for about a third of all the cropland in the U.S. The report comes from Ceres. That's an organization that works with investors and businesses to adopt sustainable practices and it details how climate change and unsustainable farming practices are threatening U.S. corn production.

Brooke Barton is author of the report. She heads the water program at Ceres and she's with me in the studio. Brooke, welcome.

BROOKE BARTON: Thank you, Jeremy.

HOBSON: Well, let's start with what climate change is doing to corn production and specifically we're talking - I guess about dry weather and drought, right?

BARTON: That's right. Just earlier this month the National Climate Assessment came out with a study of the United States and all of the impacts that climate change is happening, but looking specifically at the corn belt and the Great Plains region where we grow a lot of our corn. They found that overall, the impacts of climate change are going to be negative in productivity of our key crops, including corn.

We're expecting to see more of the sort of extreme drought and heat that we've seen in the past recent years - so devastating heat waves, more infrequent precipitation. And that's a big deal because these are areas of the country where we're already relying on really strained groundwater supplies to irrigate corn and a lot of that ground water is not going to be around for the long run.

HOBSON: Well, and that's another thing that you bring up is that corn takes up more groundwater for irrigation than any other crop.

BARTON: That's right. And corn is a really thirsty crop. So in parts of the country where we don't have ample rain we're irrigating it usually with groundwater, like from the aquifer that we have in the middle the country called the High Plains aquifer, which is a tremendous ground water resource.

It really is the lifeblood of states like Nebraska and Kansas but the fact is that the amount of water that's required to grow corn is much more than what's required to grow crops that have been traditionally been grown in those areas like sorghum or wheat. But the high price of corn has driven production in those areas. Ethanol mandate as well has encouraged production in those areas and we're seeing, in our report, that there's a least 20 counties in Nebraska, Kansas and Texas that are seeing groundwater's precipitously drop as a result of corn production.

HOBSON: Well, and you say the high price is driving production, that may be confusing to some people. What that means is that farmers decide that since the price of corn is so high, which it has been because of the drought and other factors since the price of corn is so high they're going to plant more corn because they want to make more money rather than planting something else in their crops.

BARTON: Right. The short-term economics of it makes sense but the long-term economics are a disaster.

HOBSON: And corn takes up a lot more fertilizer than other crops.

BARTON: That's right. Another big issue we see with corn production is the fact that it needs so much more fertilizer than other crops. And in many parts of the corn belt we see high levels of fertilizer pollution.

Fertilizer that essentially is running off into rivers and streams and a lot of it's aggregating into the Mississippi River and pouring out into the Gulf of Mexico contributing to, what's been called by scientists, the dead zone. It's a hypoxic oxygen-deprived area where essentially there's no room for aquatic life and we know, from our study, that corn production contributes to 40 percent of that nitrogen pollution.

HOBSON: And when we think about what this corn is used for - I grew up in corn country - right in the middle of Illinois. But a lot of the corn that was grown around me and a lot of the corn that is grown across the country is not for human consumption, it is for animal feed and it is for ethanol.

BARTON: Yeah. That's right. It's important for people to understand that the corn on the cob that we eat at barbecues in the summer is not the same kind of corn we're talking about. It's not the same kind of corn that's being grown on most of those acres across our country - what's known as Dent corn is the majority of it.

And indeed about 75 percent of that goes to feeding the cattle that go into our Big Macs, you know, feeding pigs and poultry. And then of course going into our gas tanks through being blended as ethanol.

HOBSON: Now, you are asking in this report for companies that need corn - corn buyers including Coca-Cola, General Mills, Unilever and Walmart to do what?

BARTON: So some of the specific recommendations include companies setting public goals to source corn and other agricultural inputs more sustainably, within a specific timeframe. So for example General Mills, Coca-Cola - they have set these goals and they say they're going to try to do it by 2020.

HOBSON: Well, what are they supposed to do when it comes to water, for example, if they're not going to use groundwater what are they supposed to use?

BARTON: Well, I think the reality is that in some of these regions groundwater is going to continue to be a source of irrigation. But there many upgrades in irrigation technologies that can be employed. The fact is that 20 percent of farmers are still using old-fashioned flood mechanisms to irrigate their corn rather than using drip irrigation or center pivots, which are more parsimonious in how water's being allocated. There's a lot they can also do to protect soil and the moisture in their soil by not plowing their soil as vigorously as they might otherwise by doing things like planting cover crops.

HOBSON: And what about with the fertilizer - how do you avoid having that run-off go right into the Gulf of Mexico and create that giant dead zone?

BARTON: Fertilizer application is something that has been studied for many, many years and there are many great practices that have been identified by scientists and agricultural experts. A lot of this is about putting the fertilizer on at the right time and the right amount.

Now, farmers understandably don't want to take risks and not apply enough fertilizer to produce the yield that they think they can produce. So there's a risk for them. But we now have technologies, soil testing approaches and even remote sensing that allows farmers to be much more precise and strategic about where, when and how much they apply fertilizer.

HOBSON: Brooke Barton is the author of the new report "Water And Climate Risks Facing U.S. Corn Production: How Companies And Investors Can Foster Sustainability." She heads the water program at Ceres. Brooke, thanks for coming in.

BARTON: Thank you.

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