In the science of agronomy, no more sacred ground exists than that of the Morrow Plots, a hemmed-in acre in the middle of the University of Illinois campus that, since 1876, has been under continuous corn production.
That sanctity, built on 131 years of measuring every millimeter, milliliter and gram of production input and crop output, serves as the unassailable backdrop to the startling discovery that the heavy use of nitrogen fertilizer in modern corn production harms, not helps, carbon sequestration in soil.
What it means. What this means, said Richard Mulvaney, one of four Illinois agronomists who conducted the soil-carbon research, is that “Under modern, high-yield cropping systems, we are literally burning up our soils through the over-application of nitrogen.”
This fact, published in the latest issue of the Journal of Environmental Quality, also suggests that over-applying nitrogen fertilizer on field crops is more likely a contributor to greenhouse gas production, a key factor in global warming, than an aid in carbon sequestration.
“It’s just the opposite of what conventional wisdom has preached since we began using heavy doses of nitrogen on crops 50 years ago,” said Mulvaney.
“My colleagues and I were simply amazed when we examined the data.”
The data is the key. Few places in the world have so much information over so many years on so little a plot of land as the Morrow Plots. It proves that our addiction to massive nitrogen injections is killing our most precious resource.
Burners. “I now view those giant anhydrous ammonia tanks injecting nitrogen all over as giant soil burners,” related Mulvaney from his campus office in the middle of a million of acres of Illinois corn, “and the farmers driving them as unguided missiles.”
If that view appears bold for normally-reserved agronomists, he and colleagues S.A. Khan, T.R. Ellsworth and S.W. Boast, were equally bold when titling their research paper for the Journal: The Myth of Nitrogen Fertilization for Soil Carbon Sequestration, (available at http://jeq.scijournals.org/).
Equally striking is that their results are nothing new. Other studies the authors encountered in their research also showed that the over-application of nitrogen burned more soil-based carbon than it ever added.
And yet the “myth” continued – even to the point that farmers now sell “carbon credits” to heavy carbon emitters as a way for the emitters to appear “green.”
Fraud. Mulvaney views such schemes as akin to “fraud because the way we farm burns, not banks, carbon.”
The Illinois agronomist stressed, however, the research does not mean farmers must wean themselves completely from nitrogen fertilizer. They should, however, “begin to apply the amount actually needed by the crop” – usually far less than what’s used today.
That’s long overdue advice, said Charles Benbrook, the former director of the Board of Agriculture at the National Academy of Sciences and presently the chief scientist at the Organic Center. He views the Illinois research as a loaded gun aimed at the head of conventional agriculture.
“It proves that the overuse of nitrogen fertilizers in agriculture creates soil microbes on steroids; microbes that burn up more organic matter in the soil than they return,” said Benbrook.
“We can’t continue this and have a sustainable food system in this country.”
Intelligent development. Sustainability was the founding principle of the University of Illinois College of Agriculture when the state’s citizens built Davenport Hall, the campus’s first ag building, in 1867.
Indeed, they didn’t want any subsequent generation to forget it because chiseled in stone the length of building’s west facade is every landowner’s – be they in Illinois, Iowa or Idaho – mission: “The wealth of Illinois is in her soil, and her strength lies in its intelligent development.”
(Alan Guebert’s Farm and Food File is published weekly in more than 75 newspapers in North America. He can be contacted at email@example.com.)
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