The Hagstrom Report

Agriculture News As It Happens

EWG report on Iowa topsoil loss conflicts with USDA measure


The Environmental Working Group has issued a report concluding that Iowa farms are losing precious topsoil up to 12 times faster than government estimates, but the Agriculture Department Natural Resources Conservation Service says that, while USDA’s National Resources Inventory also found high erosion rates in Iowa, the EWG report and USDA studies cannot be compared because they use very different erosion models.

USDA’s National Resources Inventory uses the Universal Soil Loss Equation and the EWG report uses the Water Erosion Prediction Project model.

The EWG report, titled “Losing Ground,” is based on research by scientists at Iowa State University who tracked erosion after every storm over a period of years. EWG says that this method provides an unprecedented degree of precision in monitoring soil erosion.

EWG, a Washington-based group best known for analyzing and releasing data on farm subsidies, also said that its aerial survey and interviews with experts across the Corn Belt indicate that soil erosion and polluted runoff are likely far worse than even the Iowa State numbers suggest.

NRCS data from April 2010 estimating 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 are “reassuring,” EWG said, but it claimed the ISU data shows these statewide or regional estimates are masking the serious damage that occurs when larger storms hit.

“What is happening on Iowa farm fields is shocking but goes largely unnoticed,” said Craig Cox, who manages EWG’s agriculture programs from its Ames, Iowa, office. Cox is the lead author of “Losing Ground.”

“We’ve grown complacent thinking we have the soil erosion problem under control, but instead it looks as if we are losing ground in our decades-old fight against this most fundamental and damaging problem in agriculture,” Cox said.

High crop prices, ethanol mandates and flawed government farm and crop insurance programs have led to “all-out production with little regard for what happens to the soil, water and wildlife habitat,” Cox said.

EWG said USDA should resume full and aggressive enforcement of provisions in the 1985 farm bill that require farmers who accept subsidies to apply soil conservation measures on the most vulnerable cropland, and require all producers participating in existing or new crop and revenue insurance programs to meet conservation compliance standard.

The agency should also reopen and revise conservation compliance plans approved and applied before July 3, 1996, the EWG said, requiring that they reduce erosion to a truly “sustainable” level and prevent ephemeral gully erosion on highly erodible cropland; require vegetative buffer zones at least 35 feet wide between row crops and all lakes, rivers and smaller streams; and adequately fund USDA’s technical staff so it can plan and implement the required conservation practices and conduct annual inspections.

An NRCS spokesman said that while USDA’s recently released Conservation Effects Assessment Project report for the Upper Mississippi River Basin found “great progress” in the reduction of sediment in the basin, “opportunities remain for improvement because 15 percent of the cropland acres are in need of additional treatment to control sediment loss due to water erosion.”

“USDA agrees that these highly erodible acres are vulnerable and should be targeted for treatment,” the spokesman said.

Though Iowa’s erosion rates remain high, the NRCS spokesman said, the number of acres in Iowa with high long-term average annual erosion rates has fallen from 17.7 million acres in 1982 to 8.4 million in 2007.

The spokesman noted that Agriculture Secretary Tom Vilsack announced the Mississippi River Basin Healthy Watersheds Initiative to improve water quality and the overall health of high priority watersheds within 12 key states in 2007, and added South Dakota to the initiative in fiscal year 2011.