Soil Erosion on Cropland 2007
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Land Use | Development | Erosion | Wetlands
About the Data | Glossary | Index of Tables
The National Resources Inventory (NRI) is a statistical survey of natural resource conditions and trends on non-Federal land in the United States. Non-Federal land includes privately owned lands, tribal and trust lands, and lands controlled by state and local governments.
The NRI provides nationally consistent statistical data on erosion resulting from water (sheet & rill) and wind processes on cropland for the period 1982-2007. To assess conservation issues this information must be analyzed in conjunction with other NRI data elements.
Soil erosion involves the breakdown, detachment, transport, and redistribution of soil particles by forces of water, wind, or gravity. Soil erosion on cropland is of particular interest because of its on-site impacts on soil quality and crop productivity, and its off-site impacts on water quantity and quality, air quality, and biological activity. Cropland includes cultivated and non-cultivated cropland.
The economic impact of mitigating soil erosion significantly burdens the agri-business sector and the Nation as a whole. Dust contributions to the atmosphere and delivery of sediment, nutrients, and chemicals to water resources are primary environmental concerns addressed by public policy makers and the stewards of our working lands. Understanding and managing these processes has important long term implications for cropland sustainability, natural resource condition and health, and environmental quality.
Key Findings
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Between 1982 and 2007, soil erosion on U.S. cropland decreased 43%. Water (sheet & rill) erosion on cropland in 2007 declined from 1.68 billion tons per year to 960 million tons per year, and erosion due to wind declined from 1.38 billion tons per year to 765 million tons per year. (Tables 18 and 19 )
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Erosion rates declined significantly between 1982 and 2007. Water (sheet & rill) erosion on cropland dropped from 4.0 tons per acre per year in 1982 to 2.7 tons per acre per year in 2007; wind erosion rates dropped from 3.3 to 2.1 tons per acre per year for the same time period. (Tables 18 and 19)
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Declines in soil erosion rates have moderated somewhat since 1997, but the general downward trend in both water (sheet & rill) and wind erosion continued through 2007.
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Due to climatic factors, soil characteristics, landscape features, and cropping practices, soil erosion is concentrated geographically.
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Water (sheet & rill) erosion (2007)—54% occurred in just two of the 10 farm production regions—the Corn Belt and the Northern Plains. (Table 36)
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Wind erosion (2007)—93% occurred in four of the 10 farm production regions—the Northern Plains, Southern Plains, Mountain, and Lake States. (Table 37)
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The nationwide trend of declining soil erosion rates on cropland was mirrored in declining soil erosion in each of the 10 farm production regions. The Appalachian region experienced the greatest decline in water erosion rates, from 6.8 tons per acre per year in 1982 to 3.2 tons per acre per year in 2007-a 53% decline over the period. The Southern Plains region had the biggest decline in wind erosion rates, from 9.9 to 6.2 tons per acre per year-a 37% decline-over the same time period. (Table 36 and Table 37)
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Among all farm production regions, combined water and wind erosion in 2007 was lowest in the Northeast (2.7 tons per acre per year) and highest in the Southern Plains (8.8 tons per acre per year). (Table 36 and Table 37)
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In 2007, 99 million acres (28% of all cropland) were eroding above soil loss tolerance (T) rates. This compares to 169 million acres (40% of cropland) in 1982. (Table 20)
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The acreage of highly erodible cropland (HEL cropland) declined from 125 million acres to 98 million acres, or 22%, between 1982 and 2007. (Table 20)
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The acreage of HEL cropland that had erosion rates above T declined from 84 million acres to 54 million acres during the 1982-2007 period-a 36% decline. (Table 20)
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The acreage of non-HEL cropland declined from 294 million acres to 259 million acres over the same period, a decrease of 12%. (Table 20)
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The acreage of non-HEL cropland that had erosion rates above T declined from 85 million acres to 46 million acres during the 1982–2007 period—almost a 46% decline. (Table 20)
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