Don McClure’s presentation at the Conservation Tillage and Technology Conference last month put some good perspective on what’s at stake with yields when soils become eroded.
McClure, a retired soil expert from the NRCS, shared a slide depicting a study done by Oklahoma State University experts that established a yield index to chronicle the effect soil eroded by raindrops had on yields in Illinois.
The chart shows a correlation between fields with favorable or unfavorable subsoils and yield losses as slopes increase. Unfavorable subsoils were defined as thinner subsoils that don’t allow for favorable root movement.
For example, in a field area with 0-2% slopes and favorable subsoil, 100% of production was realized in uneroded soils, followed by 97% with moderate erosion and 90% with severe erosion.
But with unfavorable subsoils, moderate erosion dropped to 95% and severe erosion to 80%.
In a field area with 5-10% slope, favorable subsoils with severe erosion were still able to get 87% of production, while that dropped to 76% in unfavorable subsoils with severe erosion. The higher the slopes, the lower the yield index fell, especially if erosion was severe.
Obviously our readers farm in a variety of topographies, from flatlands to steep rolling hills. But the message here is that thin, eroded soils cost you money. With tight times ahead, shouldn’t we be leaving as much of soil in our fields as we can?
In our main feature today, Gainesville, Texas, no-tiller Andy Popp discusses how he ditched the plow on his farm several years ago and started seeding cover crops to improve both soil health and forage options for his cows and calves. He pointed to a creek in one field that was always dry except during heavy rains, but is now flowing with water after his soil management changed.
“Now I drive by guys that I know are good conventional farmers, but see how much they battle fixing terraces and all the washing,” Popp told me recently. “They’re letting their places wash away.”