On Sunday, outgoing Iowa DNR director Richard Leopold shared some final thoughts about the state of Iowa’s environment in a Des Moines Register guest column. There, he lamented about the state’s lack of progress in cleaning its rivers, it’s underfunded state parks, and the politicization of science (“Sadly, many of the scientific “debates” of today are not scientific debates; they are about power and money.”).
Leopold also shared a startling statistic about Iowa’s increasing infertility:
When you are out of dirt, you’re done. Consider these facts: Iowa started the turn of the 20th century with an average of 16 inches of topsoil. Iowa now has an average of seven inches of topsoil. We continue to lose, on average, about 1/16 of an inch of topsoil per year to erosion – about 250 million tons! Add to this the effects of local flooding and overuse of chemicals, and many of our soils look tired and spent. Given the gift of some of the best soil on the planet, we must do better.
For a state that depends on agriculture for its economic survival, that news should spur farmers and other land managers to make some changes.
Water runoff after heavy rains is a key contributor to erosion. As water runs off the land, it takes valuable nutrients with it (And incidentally, those nutrients are primary pollutants that make our rivers dirty).
Farmers can limit runoff and erosion by planting cover crops between rows of farmland. Those crops hold water in and hold the soil together.
For more information, see the Powerpoint presentation on floodplain management strategies here.