Losing top soil

Last year, the US Department of Agriculture’s Natural Resources Conservation Service estimated that the rate of soil erosion on agricultural land averaged only 5.2 tons per acre per year in Iowa and 3.9 tons per acre per year across the Corn Belt. On the surface, this data was reassuring, because it suggested erosion was within the so-called “sustainable rate.” But a more precise look udertaken through a project run by Iowa State University shows that these statewide or regional estimates are masking the serious damage that occurs when larger storms hit.
“When a storm hits vulnerable or poorly protected soil, fields lose more soil in a single day than is supposed to be sustainable for the whole year, or even decades,” said the University's program head. “If we had the same kind of information for other intensive corn-growing states, the picture would be the same or worse. Alarm bells should be going off across the Corn Belt.”
Farmers are planting fencerow-to-fencerow in response to high crop prices that are likely here to stay. Misguided mandates for corn ethanol production add fuel to the fire, and flawed government farm and insurance subsidies clear the way for all-out production with little regard for what happens to the soil, water and wildlife habitat.
We don't get subsidies in Australia, but there is no reason to believe that things are any better here.
More details at:
http://www.rodaleinstitute.org/20110413_soil-erosion-in-corn-belt-much-worse