When prices for corn and soybeans surged last fall, Bill Hammitt, a farmer in the fertile hill country of western Iowa, began to see the bulldozers come out, clearing steep hillsides of trees and pastureland to make way for more acres of the state’s staple crops. Now, as spring planting begins, with the chance of drenching rains, Mr. Hammitt worries that such steep ground is at high risk for soil erosion — a farmland scourge that feels as distant to most Americans as tales of the Dust Bowl and Woody Guthrie
Long in decline, erosion is once again rearing as a threat because of an aggressive push to plant on more land, changing weather patterns and inadequate enforcement of protections, scientists and environmentalists say.
“There’s a lot of land being converted into row crop in this area that never has been farmed before,” said Mr. Hammitt, 59, explaining that the bulldozed land was too steep and costly to farm to be profitable in years of ordinary prices. “It brings more highly erodible land into production because they’re out to make more money on every acre.”
Now, research by scientists at Iowa State University
provides evidence that erosion in some parts of the state is occurring at levels far beyond government estimates. It is being exacerbated, they say, by severe storms, which have occurred more often in recent years, possibly because of broader climate shifts.
“The thing that’s really smacking us now are the high-intensity, high-volume rainstorms that we’re getting,” said Richard M. Cruse, an agronomy professor at Iowa State who directs the Iowa Daily Erosion Project
. “In a variety of locations, we’re losing topsoil considerably faster — 10 to as much as 50 times faster — than it’s forming.”
Erosion can do major damage to water quality, silting streams and lakes and dumping fertilizers and pesticides into the water supply. Fertilizer runoff is responsible for a vast “dead zone,” an oxygen-depleted region where little or no sea life can exist, in the Gulf of Mexico. And because it washes away rich topsoil, erosion can threaten crop yields. Significant gains were made in combating erosion in the 1980s and early 1990s, as the federal government began to require that farmers receiving agricultural subsidies carry out individually tailored soil conservation plans.