And there isn’t. Cruse will show you aerial photos of the Des Moines lobe—the corn capital of the world—where the precious topsoil depth has shrunk from fourteen inches to nothing in the span of a century. It starts on the knobs and spreads to the flat ground as the wind whips water across the bare black slate where you don’t see a tree for miles.

Soil erosion rates have amplified since the 1980s because of more extreme weather combined with less land in pastures and buffers and intensified row-crop production that packs much higher plant populations per acre.

Soil can hold water during drought, but if there is less soil in place, resiliency weakens. Cruse, who runs the Iowa Daily Erosion Project, tells us that our Iowa and Illinois prime cropland is floating downriver.

Cruse has been taking his analysis around the state trying to get people to listen: Climate change is upon us. The only way we can continue to reach optimum corn production in an increasingly hungry world is to maintain the soil base that the Good Lord left us when the plow arrived after 1850. We can’t do that the way we are farming—all out on virtually every acre.

Buena Vista County’s flat land is losing soil four times faster than nature can regenerate it. Iowa can regrow up to a half ton of soil per acre per year. Federal authorities say five tons per acre lost annually is “acceptable.” Such acceptable losses are common after a two-inch rain. We are losing soil way faster than we can grow it.

Cruse notes that corn potential is derived from genetics, man- agement, and water transpiration. You can get the best genetics and get plant populations as high as possible, but you can reach that crop’s potential only with adequate water. Topsoil, rich in organic matter, stores water for the corn plant. For every inch of topsoil you lose, corn production capacity is lost with it.