Cropland Erosion Declined 43% Over Past 20 Years
USDA study showed Missouri and the Souris-Red-Rainy/Upper Mississippi River Basins showed the most significant reductions in erosion levels.
Compiled by staff
Published: May 23, 2006
Total soil erosion on cultivated and non-cultivated cropland in the U.S. decreased 43% between 1982 and 2003, sheet and rill erosion decreased 42%, and wind erosion decreased 44%, according to USDA's National Resources Inventory, a statistical survey of natural resource conditions and trends on non-federal land.
Nationwide, sheet and rill erosion, which is the removal of layers of soil by rainfall and runoff, on cropland dropped from 4 tons per acre per year in 1982 to 2.6 tons per acre per year in 2003. Wind erosion rates also dropped from 3.3 to 2.1 tons per acre per year.
The data also shows that 72% of the nation's cropland was eroding below soil loss tolerance rates, compared to 60% in 1982. Highly Erodible Land being cropped is down to about 100 million acres, compared to 124 million acres in 1982. HEL cropland acreage eroding above soil loss tolerance rates declined 35%. Non-HEL cropland acreage eroding above soil loss tolerance rates decreased 45% between 1982 and 2003.
The Missouri and the Souris-Red-Rainy/Upper Mississippi River Basins -approximately 50% of our nation's cropland - experienced the most significant reductions in total erosion from 1982 to 2003. In the Missouri River Basin, which includes sections of Colorado, Iowa, Kansas, Minnesota, Missouri, Montana, North Dakota, South Dakota, and Wyoming, and all of Nebraska, the average rate of soil erosion fell 3 tons per acre per year.
The Souris-Red-Rainy/Upper Mississippi River Basin, which includes sections of Illinois, Indiana, Iowa, Minnesota, Missouri, North Dakota, and Wisconsin, fell 2.5 tons per acre per year.
The NRI, conducted by USDA's Natural Resources Conservation Service in cooperation with Iowa State University, shows that the total tons of soil erosion declined in all major river basins. The study also shows a downward trend in both sheet and rill erosion and wind erosion continued through 2003.
The NRI is an assessment of soil erosion, land cover and use, prime farmland soils, wetlands, habitat diversity, selected conservation practices and related resources. Data is gathered from 800,000 sample sites on non-federal land in all 50 states, Puerto Rico, the U.S. Virgin Islands and some Pacific Basin locations. The NRI is used by natural resource managers, policymakers, analysts, consultants, federal agencies, state governments, universities, environmental, commodity, farm groups, and the public to address agricultural and environmental issues at national, regional and state levels.
For more information on the results of the cropland erosion study, visit www.nrcs.usda.gov/technical/NRI. For soils information, visit soils.usda.gov.
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Tagged: usda, NRCS, farm, Natural Resources Conservation Service
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