"What a difference a year makes. Last year at this time, the Midwest was heading into one of the worst droughts in decades. Now much of the region is soggy. But the biggest loser from this year's heavy rains? The land itself."

"The Environmental Working Group, drawing on analysis done by Iowa State University's Iowa Daily Erosion Project, found in a recent report that during one five-day period in May, 50 townships in Iowa lost more than 5 tons of topsoil per acre.

As EWG puts it: 'Those 1.2 million acres of farmland may have lost more precious topsoil in five days than what is tolerable over an entire year.' The U.S. Department of Agriculture's Natural Resources Conservation Service considers an annual rate of topsoil loss of five tons 'tolerable,' but EWG says 'a truly sustainable rate of erosion is far lower.'"

Daniel Charles reports for NPR's The Salt blog July 12, 2013. [2]