Agriculture Deputy Secretary Kathleen Merrigan announced on April 27 that soil erosion on cropland declined by more than 40% during the past 25 years, while more than one-third of all development of U.S. land occurred during the same period. The information was contained in the latest National Resource Inventory (NRI) for Non-Federal Lands, which was released at an event marking the 75th Anniversary of USDA's Natural Resources Conservation Service (NRCS), the agency charged with ensuring private lands are conserved, restored and more resilient to environmental challenges.
"The NRI results are significant because they provide a scientifically based snapshot of the nation's natural resources and the ability to track trends in natural resource use and condition," Merrigan says. "The NRI provides a wealth of information that can be used by agricultural and environmental policymakers to make informed decisions about the nation's natural resources."
Key findings from the 2007 NRI include:
Total cropland erosion (sheet, rill and wind) declined by about 43%, from more than 3.06 billion tons/year in 1982 to about 1.72 billion tons/year in 2007. The reduction reflects NRCS's emphasis on working with producers and landowners to reduce erosion. Most of the soil erosion reductions occurred between 1987 and 1997.
Cropland acreage declined from 420 million acres in 1982 to 357 million acres in 2007, a 15% decrease. About half of this reduction is reflected in enrollments of environmental sensitive cropland in USDA's Conservation Reserve Program.
About 40 million acres of land were newly developed between 1982 and 2007, bringing the national total to about 111 million acres. More development occurred in the Southeast than in any other region. For the NRI, developed land includes rural transportation corridors such as roads and railroads as well as urban and built-up areas, which include residential, industrial, commercial and other land uses. The findings on development are important because development isolates tracts of former farmland, which degrades wildlife habitat and makes agricultural production inefficient.
There were 325 million acres of prime farmland in 2007, compared to 339 million acres in 1982. The acreage of prime farmland converted to other uses such as development during the 25-year period is greater than the combined area of Vermont and New Hampshire and almost as large as West Virginia.
The total area of developed land in all states, except Alaska and Hawaii, is approximately equal to the combined surface area of Illinois, Iowa and Michigan. Land that was newly developed between 1982 and 2007 covered an area slightly larger than Iowa. The largest increase in development was 10.7 million acres between 1992 and 1997.
