Illinois corn farmers were celebrating Thanksgiving with record yields and prices. The state's rich earth has been good to us, especially the one million acres planted in corn. Congratulations would be in order were it not for a very, very, dark side to this story. The headline should read, "The Golden Earth is becoming scorched earth."
It's been suggested for years that over-application of nitrogen fertilizer, while delivering high yields, is actually destroying the soil that gives us our food. Four agronomists from the heart of corn country—the University of Illinois—have delivered the most important research yet in The Journal of Environmental Quality. Over-applying nitrogen fertilizers, they report, causes soil microbes to use up organic matter that normally would keep the soil healthy.
It means that we're ruining our soil and if we don't stop this nitrogen-worship to achieve bigger, richer yields every year, the Illinois golden cornfields will become a dark brown wasteland.
University of Illinois scientist Robert Mulvaney, with input from S.A. Khan, T.R. Ellsworth and S.W. Boast, told me, "Our message is not a doomsday scenario, but does provide compelling evidence of a need to improve nitrogen fertilizer management."
Their research will crack open the earth beneath the industrial agriculture establishment because it comes from the Morrow Plots on the U. of I. campus, the world's oldest experimental site under continuous corn production and widely regarded as sacred ground in agricultural research.
Such authority makes the new research almost irrefutable, and worse, it comes with the greatest irony imaginable. Ethanol, fueled by corn, is driving corn prices to record levels, encouraging farmers to push yields even higher which means more and more nitrogen fertilizer will be spreading across Illinois fields. It is, indeed, the best of times and the worst of times.
But there's more. It has been widely believed that growing plants like corn help fight global warming by holding carbon in the soil, much like making a deposit in a bank. Farmers even sell "credits" to large carbon emitters who are allowed to burn more carbon because the Illinois cornfields offset their emissions.
The University of Illinois research turns that belief on its head. The title gives it away, "The Myth of Nitrogen Fertilization for Soil Carbon Sequestration." The scientists were amazed at what they found. Mulvaney writes, "All indications are that excess nitrogen stimulates microbial decomposition of organic carbon, not only from crop residues but also the native soil organic matter (humus)." So, after excessive nitrogen fertilizer use, there's not much carbon left to sequester.
The best carbon sequestration ultimately goes back to native prairie, the kind of tall grasses that so amazed the first Europeans who saw them. Big blue stem roots descended fifteen feet into the rich earth, weaving a prairie sod of organic matter, imprisoning more carbon than a rain forest.
I suppose with enough time we could become the prairie state again, but that's not being realistic. Our better chance is to change our agricultural practices. Currently, we care primarily about high yields, achieved with nitrogen chemicals, like putting our fields on methamphetamines.
We should listen to the four agronomists who say, "For the sake of future generations as well as our own, a shift is needed toward a multi-functional approach that is ecological as well as economic in nature."
That shift would be to start using the right amount of nitrogen fertilizer for the land instead of over-applying it to boost yields. It will still take several decades to reverse but it's better than the alternative.
We should listen to the land.
—Bill Kurtis, Chairman and Founder of Tallgrass Beef Company