In 2021, a team of researchers from the University of Massachusetts Amherst estimated that croplands in the US Midwest were losing topsoil at a frightening rate—fast enough that it’s been eradicated completely from over one-third of the US Corn Belt.
They’ve now taken their earlier work a step further, demonstrating that an already commonplace agricultural practice could bring this destruction to a standstill—or even reverse it.
They plugged their original numbers into a model that simulated regional soil degradation decades into the future, showing what would happen if current rates of soil loss remained unchanged—or alternatively, if we did something about it.
They didn’t imagine a whole new technology, but rather focused on a methodology that is shovel-ready. No-till farming methods are already practiced across 40% of the farming area the researchers focused on, and so they simulated what would happen if we expanded a softer version of these measures over a larger area of land.
This revealed that on the one hand, if we stick with conventional farming methods and unbridled tilling goes on, it will whittle away at the topsoil and drive losses of 8.8 billion metric tons over the next 100 years. That would also release 170 million metric tons of organic carbon that’s currently locked into this crucial surface layer.
However, this dire picture could be almost entirely reversed, if farmers adopt low-intensity till practices across the studied area. Unlike no-till methods, this alternative would still allow this practice but at a reduced rate, and may also involve incorporating crop residue onto the surface to further buffer soil from erosion.
The researchers’ model showed that expanding such practices across the entire midwestern region could reduce projected soil losses by 95% over the next 100 years. The pace of loss would be so significantly slowed down by these measures, in fact, that it would take 10,000 years to reach the levels of soil loss that will unfold in just a century, if regional farming methods don’t change at all. The fact that all this can be achieved with a watered down version of the no-till that is already practiced across parts of this region, is an encouraging sign.
In conversations about sustainable agriculture that often focus on important issues like making crops more adaptable, reducing fertilizer and pesticides, and increasing yields, soil health often gets overlooked. Yet this is where all the agricultural action happens, especially in the rich surface layer where crops take root and are nourished, and which is also especially vulnerable to erosion.
This oversight is already costing crops: soil degradation in the Midwest has so far reduced yields by 6%, costing an estimated $2.8 billion, the researchers explain in their study. And since degradation happens much faster when there’s more soil to degrade, now would be the optimal time to intervene to stop this economic and agricultural loss, they say. “There’s real incentive to act now when we’ll see the most long-term benefit.”
Kwang et. al. “The Future of Soils in the Midwestern United States.” Earth’s Future. 2023.