Let's Talk Dirt

 

When I was a child I went to visit my grandfather's farm outside Leamington. The fields that would soon deliver an abundance of tomatoes for Heinz or sweet corn and peas for Green Giant were freshly tilled revealing the rich, black soil that was the key to their productivity.

I didn't think of soil very much until recently when I took a few online courses in global food security. That's when I learned how, in our quest to feed eight billion people, we have resorted to excessive industrial agriculture.

Yale360 reviews a report on the decline of that once rich farmland across the American midwest.

You hear many different numbers regarding that black Iowa soil. It’s often repeated that the topsoil — the nutrient-rich A horizon — was some 14 to 16 inches deep when the prairie was first broken, a fantastic depth of fertility rivaled only by some regions in the Ukraine. By the mid-1970s — roughly a century after the prairie was broken — it was reported that, in places, half of that topsoil had already been lost to erosion from wind and runoff.

In late February, three geoscientists from the University of Massachusetts — Evan Thaler, Isaac Larsen, and Qian Yu — published a paper called, “The extent of soil loss across the U.S. Corn Belt.” ...The number they arrived at is shocking. “We predict,” they wrote, “[that] the A-horizon has been completely removed from 35±11% of the cultivated area of the Corn Belt.” Plus or minus 11 percent is a large range of uncertainty. But its meaning is plain. At best, 24 percent of the topsoil in the Corn Belt has been completely removed by farming. At worst, 46 percent has been lost.

It’s worth being clear here. The authors aren’t talking about reduced soil fertility or loss of mineral nutrients. They’re talking about the complete removal of the medium in which crops are grown — the utter bankruptcy of the organic richness that lay for centuries under the tallgrass prairie. The authors argue, in a sense, that we’ve been farming in the dark, though they’re never quite that blunt.

Inevitably, the paper goes on to calculate the economic implications of these findings. And that’s how the agricultural press (which has scarcely noticed this study so far) has read it: The loss of topsoil on 30 million acres may result in a possible $3 billion annual loss “to Midwestern farmers.” I have to admire the narrowness of that interpretation, which is completely consistent with the economic assumptions that have governed industrial farming since World War II. The catastrophic loss of an irreplaceable resource — what you might call an essential part of our common earthly heritage — is construed as an annual loss of income to the farmers who operate those farms. The narrowness of these assumptions — driven by official U.S. Department of Agriculture policy and the shared economic interests of chemical and seed companies — has made it possible to farm in a way that is little more than slow strip-mining.

...Good farming should mean ongoing carbon sequestration. Agricultural land should be a carbon sink. But as practiced now — with massive reliance on fossil fuels, on soils stripped of organic carbon — industrial farming is a major contributor to the global crisis of atmospheric carbon.

So they've lost six or seven inches of topsoil in the Corn Belt, so what? To put this in perspective, it takes anywhere from 100 to 500 years or more to generate just one inch of topsoil. There is also the depletion of soil carbon that necessitates the application of ever greater quantities of chemical fertilizers, a vicious cycle that undermines soil productivity. Then there's the once mighty Ogallala aquifer that underlies the eight states making up America's grain belt. Parts of it are already drained, the water pumped out for irrigation. The remainder is heading in the same direction.

The most worrisome part is our indifference to this looming threat to our own food security.  Agronomists have been churning out studies for the past 20 years. They've been warning anyone who will listen.  So too has the UN Food and Agriculture Organization. But who is listening? 

Oh, I suppose they'll think of something. Right?