by Brian Devore • 11/6/08 • Ethanol in Olmsted County
Recent charges that the MPCA has been giving proposers of an Olmsted County ethanol plant most favored customer status need to be taken seriously: putting up a facility that will pump millions of gallons of water out of karst aquifers is no laughing matter. And it’s not just the direct environmental impacts of this facility that warrant scrutiny. One indirect impact of a giant ethanol plant in the region—more corn on the landscape—is of particular concern at a time when corn fertilizer pollution is already a major problem in the region.
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Corn is a nitrogen hungry plant, and so more corn on the land means more nitrogen in the environment. As I outline in the Autumn issue of the Land Stewardship Letter, the last thing southeast Minnesota needs is more nitrate-nitrogen in its groundwater—it’s already a major pollution problem in the region, one that’s growing worse by the year. As more pastures, hay fields and even small grain plantings are replaced by corn to feed the ethanol maw, more nitrogen fertilizer is being applied to keep yields high. A lot of that nitrate-nitrogen is making its way into groundwater, and not just in vulnerable karst regions like southeast Minnesota.
In 2007, the USDA’s Economic Research Service (ERS) and its Office of the Chief Economist concluded that as corn production for biofuels increases, nitrogen fertilizer use will go up around 6 percent in the Midwest. The amount of nitrogen leaching into groundwater will be 2.4 percent higher in the Corn Belt by 2016, and 10.6 percent higher in the Lake States, according to the ERS. The increase in corn cultivation required to produce 15 billion gallons of ethanol by 2033 will increase the amount of nitrogen in the Gulf of Mexico by at least 10 percent, according to a study published in the Proceedings of the National Academy of Sciences in March.
Nitrogen in water is both a human health concern and an environmental problem. High nitrate levels can lead to “blue baby syndrome” in infants, a type of asphyxiation. In addition, studies have linked consumption of water containing high levels of nitrates to health problems in adults, including bladder cancer.
On a landscape level, high nitrates in water can lead to increased algal growths, which begins a chain reaction that can reduce oxygen levels in bodies of water to the point where they can’t support aquatic life. A big cause of the Gulf of Mexico’s “dead zone”—a low-oxygen area that in 2008 measured 8,000 square miles—is nitrogen and phosphorus fertilizer runoff from Midwestern farm fields. The number of dead zones in coastal waters worldwide is now 405, an increase of a third between 1995 and 2007, according to the Virginia Institute of Marine Science.
Back in southeast Minnesota, researcher Kshama Harpankar recently analyzed the “externalized” costs of increased ethanol production as they relate to higher nitrogen contamination rates in Olmsted County. In other words, how do we account for those costs that usually aren’t recognized by the marketplace? Harpankar, who did this study as part of her doctoral work in applied economics at the University of Minnesota, looked at several scenarios, including land under a corn-soybean rotation shifting to continuous corn—a likely evolution if a new ethanol plant increases demand for maize.
Other scenarios included cutting corn acreage by 25 percent, or by half, and Conservation Reserve Program acreage increasing. What she found was that when corn acreage increased, the number of domestic wells with nitrate-nitrogen levels that were above 10 parts per million (the state and federal health limit) rose dramatically. When corn plantings were reduced, wells with dangerously high levels of the contaminant dropped—all the way to zero in one case where corn acreage was halved.
But then Harpankar took a look at how profitable it was to raise row crops in Olmsted County in 2007. What she found was that, for example, shifting land in a corn-soybean rotation to continuous corn would generate much more revenue for farmers than it would cost to clean up private wells contaminated with nitrate-nitrogen. In other words, it may make economic sense to pollute and treat the problem, rather than to prevent the contamination in the first place.
But as Harpankar points out, it’s not that simple. Because of the sometimes mysterious ways nitrate-nitrogen moves within the soil and in water, in many cases the farm that produces excess amounts of the chemical is not the one that suffers from well contamination.
Indeed, scientists have been perplexed at how high nitrate-nitrogen levels can vary significantly in wells literally yards apart. It can be very difficult to predict the chemical’s movements, particularly in groundwater, which also has a mind of its own.
“We must keep in mind that these are costs that will not be seen for a number of years,” Harpankar told me. “A farmer in Minnesota or somewhere else uses something and it shows up years down the road, and it can show up in places far away like the Gulf of Mexico. That’s a problem for all these externalities—it’s hard to go back to the source and assess the damage.”
No kidding. I’ve talked to southeast Minnesota farmers who are doing everything right when it comes to reducing nitrogen contamination. They’re rotating crops to lower their reliance on nitrogen fertilizer, utilizing well-managed pastures to reduce runoff and doing a better job of using only as much nitrogen as their corn needs. Recent U of M research has shown these kinds of farming methods can reduce nitrogen contamination significantly. And yet, in come cases the well water of farmers who are reducing nitrogen runoff can still test for dangerously high levels of the contaminant.
“That’s one thing you can’t control, is the water vein,” Arlene Nelson recently told me. Nelson, who with her family has an organic dairy farm in Winona County, utilizes pastures and diverse cropping mixes. They haven’t used nitrogen fertilizer since the mid-1990s. This spring, they were forced to drill a new well because of extremely high nitrate-nitrogen readings. “It’s very hard to pinpoint all of this. Sometimes a neighbor will say, ‘Well, our water test is below 10 parts per million,’ even when yours is extremely high,” she said with more than a hint of exasperation in her voice.
This valuable source of fertility is infamously difficult to track and control once it hits the soil and goes subterranean. Taking isolated steps to control it won’t work. We need a comprehensive approach that includes promotion of diverse, sustainable farming practices on a landscape level.
And that may mean taking an even harder look at proposed developments that will promote a nitrogen-intensive type of agriculture. They may be good “customers” to the MPCA, but their economic development could come at a price we can’t afford.