Washington, D.C. – More than 1.2 million acres of farmland in Iowa lost more precious topsoil in five days of heavy rain this spring than what is considered tolerable for an entire year, largely because of inadequate conservation practices, a new EWG analysis shows.
To show just how bad things looked on the ground, EWG researchers toured nine counties in central Iowa to map and document the effects of the intense spring rain on farm fields. The tour revealed widespread serious erosion everywhere conservation practices were missing, not just on land considered highly erodible.
Click here to see EWG’s unique interactive map with photographs of each location surveyed.
The report, titled “Washout,” focuses on the May 25-29 period when a series of heavy rainstorms rolled across Iowa.
According to EWG’s researchers, however, where basic conservation practices were in place and properly maintained, there was little damage to farmland. Tragically, most fields were unprotected and exposed to the full force of the storms.
“Heavy rain is nature’s doing, but the resulting erosion and polluted runoff is entirely a man-made disaster,” said Craig Cox, EWG’s senior vice president of agriculture and natural resources. “We can do a great deal to protect Iowa’s fields and streams. Full enforcement of the so-called ‘conservation compliance’ provision in the federal farm bill is a good place to start.”
That provision, first enacted in 1985, requires farmers to carry out simple conservation steps as a condition for receiving taxpayer-funded subsidies. When it was fully enforced, this long-standing quid pro quo succeeded in cutting erosion by 40 percent on the most highly erodible cropland.
Data from the Iowa Daily Erosion Project (IDEP) at Iowa State University, confirmed what EWG’s researchers saw on their tour. EWG’s analysis of those data found that erosion averaged more than five tons of soil per acre over the five days in 50 Iowa townships covering 1.2 million acres. In 15 of those townships encompassing 346,000 acres, fields suffered average erosion of 7.5-to-13 tons per acre. On vulnerable and/or poorly protected farmland in a total of 115 townships, the hardest-hit fields lost more than 20 tons of topsoil per acre in less than a week.
The damage estimates are far more than the annual erosion rate of five tons/acre considered “tolerable” for most Iowa soils by the U.S. Department of Agriculture’s Natural Resources Conservation Service. And most soil scientists believe a truly sustainable rate of erosion is actually far lower than the government figure.
“The picture these data paint is incredibly devastating, but the reality on the ground in Iowa and across the heartland is even worse,” said Craig Cox, “The storms that have been battering the region’s unprotected cropland soil have sent tons of dirty mud and farm chemicals into our road ditches and waterways.”
The report notes that the Daily Erosion Project data do not take into account the effects of ephemeral gullies, which cause the worst erosion and polluted runoff. Although growers repeatedly plow over these gullies, most of them flow to streams, creating a direct pipeline carrying pollutants into rivers or drainage systems.
This spring’s rains were particularly destructive, but storms ravage the Midwest’s fertile soil and streams every year. In April 2011, EWG’s Losing Ground report and video showed that some parts of Iowa had suffered serious damage nearly every year between 2002 and 2010, and almost all of the state’s farmland eroded at some point during that time period.
“The solution to the environmental abuse does not require decades of research and preparation,” Cox said. “Our government leaders need to show leadership and political will.”
