From a pal in Iowa

According to USDA official estimates of soil loss rates, which most experts agree are too low, and researcher estimations of soil replacement rates, which are probably optimistic, Iowa rowcropped land loses soil every year, on average, at least ten times as fast as it can be replaced, and the real figure is very likely closer to thirty times as fast. Also, when I clicked on the "conservation measures" link in the third paragraph, I was informed "this address is not valid." Talk about appropriate, bwaha. And of course a lot of the new acres are coming out of CRP. I was in our county NRCS office this afternoon and asked if there has been a good response to the new general CRP signup. "No," the staffer told me. "But I'm talking to a number of people who want to pay off their existing CRP contracts so they can start planting corn again."
http://www.iowafarmbureau.com/article.aspx?articleID=56646