March is said to be the month of winds, which perhaps means the originators of the saying didn’t live in a prairie for we seem to have winds all year long. Especially in the wintery months. When you subject that constant with farming practices that perhaps began with the first of the early settlers you can only imagine the result. Well, you really don’t need to imagine, for a drive along most any rural road will illustrate the sad results.
If it were not for the contrast given by the snow perhaps the unaware would likely miss seeing all the fine particles of dirt blown into the roadside ditches and across the windswept prairie. A few days ago my friend and fellow blogger, Jim VanderPol, and his wife, LeeAnn, drove to the edge of their mostly grassed farm where they raise hogs and cattle on perennial grasses to catch a glimpse of a late February wind and the results of a winter’s worth of windblown soils from a neighbor’s tilled and bared field.
LeeAnn filmed a short video of Jim walking into the muck covering his grasses where he bent down, grabbed a handful chilly mud before disgustedly wiping it off his hand. Behind him the near horizon was a hazy brown, which for Chippewa County is far too common. The mud blanketed his grass for nearly 40 feet fron inside the fence (catch the video on his blog at http://www.pasturesaplenty.com).
Several miles north of the VanderPol’s, on a hillside overlooking the Pomme de Terre River, so much dirt has blown off a field that the complete hillside, which is a grassed meadow, is entirely blackened with the dirt blown from an adjoining crop field. This is a valley hillside of the Pomme de Terra River, meaning that some of that dirt will eventually seep into the river. If not the soil, then the washable nutrients placed on the crops and embedded in the dirt are certain to drain into the river.
Roadside ditching are thick with wind-eroded dirt. Some on both sides, and on one stretch of a county road near here there is more than a mile long where drainage ditches on both sides are blackened with wind-eroded dirt. So thick you cannot tell where the field edge exists. Not on the same road is a farm home where an entire yard was encrusted in black through the winter. Dirt that had blown across the highway to become clogged in the drifts of snow duned by the trees in the adjacent grove before lapping around the northwest corner of the house and into the front lawn. Besides the house, the only object not covered in blackness was the propane tank! All from a field across the highway.
These on-site observations comes on the heels of a report published in late February by three geoscientists from the University of Massachusetts … Evan Thaler, Isaac Larsen and Quin Yu … called “The Extent of Soil Loss Across the U.S. Corn Belt.” Their use of high definition satellite imagery across an eight-state Corn Belt swath, including Minnesota, showed that A-horizon (nutrient-rich topsoil) was essentially no longer present on convex slopes. If you’re crossing the former prairie and current commodity crop complex this evidence are all those tan or light brownish spots you see on the rises in the fields where the topsoil has eroded – what VanderPol was holding in the palm of his hand in the video. “The A-horizon was almost always gone on hilltops,” says Thaler.
The low areas are medium to dark brown on the satellite imagery, which is where some of the A-horizon soil has eroded to. When the prairie was first broken a century and a half ago, those soils, including what you now see as tan B-Horizon sub-soils, was covered with about a foot and a half of fertility rich topsoil. By the mid-1970s nearly half that topsoil had already been lost to both wind and runoff erosion. Despite such conservation efforts as contour plowing and various set-aside strategies that paid farmers to keep marginal land out of production, the soil losses continued. This was more than 50 years ago and the erosion continues on soils that are left bare from fall plow-down in October and November until there is some sort of plant protection by the following June. In other words, soils are left unprotected for nearly nine months.
The geoscientists calculated that about a third of the crops are being grown on erosion-prone soils. That estimate is far higher than those published by the U.S. Department of Agriculture. “I think the USDA is dramatically underestimating the amount of loss,” Thaler adds.
This isn’t a pretty sight, and it’s also a dangerous one. In his sobering book, “Dirt: The Erosion of Civilizations,” David R. Montgomery wrote, “Projecting past practices into the future offers a recipe for failure. We need a new agricultural model, a new farming philosophy. We need another agricultural revolution. Unlike the first farmer-hunter gatherers who could move around when their soil was used up, a global civilization cannot.”
In other words, this is it: we are growing crops on the earth’s very last productive soils. “The estimated rate of world soil erosion now exceeds new soil production by as much as 23 billion tons per year, an annual loss of not quite one percent of the world’s agricultural soil inventory. At this pace, the world will literally run out of topsoil in little more than a century,” adds Montgomery. “It’s like a bank account from which one spends and spends, but never deposits.”
Once again there are farming techniques that might preserve these last few inches of productive topsoil including using cover crops. Those farmers who have bitten the bullet to integrate cover crops into their cropping repertoire have reported some significant benefits even beyond protecting their soils from erosion. Better water retention, a disruption of weed issues and less compaction, among them. Perhaps what is known as “conservation tillage” has helped in some degree, although driving past those fields indicates “not much.” Perhaps the least expensive alternative is to simply leave the corn stalks untilled until just before planting … when the soil is worked once again regardless. On soybean and sugarbeat fields, there is little to no protection whatsoever.
Someone even suggested that perhaps a solution to change would be to forbid those guilty of such erosion should lose their crop subsidy benefits. Regardless, too much of the remaining topsoil is subject to both wind and runoff erosion, and there appears to be quite a lackadaisical attitude among those who tend to the land. How many times have we asked one another as we drove past those miles upon miles of dirt covered roadside ditches, “Don’t these guys even notice the erosion?”