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National Soil Erosion Results Tables

2007 National Resources Inventory

Estimates presented here are based upon the latest information from the National Resources Inventory (NRI). The NRI is a longitudinal sample survey based upon scientific statistical principles and procedures. It is conducted by the U.S. Department of Agriculture’s Natural Resources Conservation Service (NRCS), in cooperation with Iowa State University’s Center for Survey Statistics and Methodology. These results are based upon the 2007 NRI, which provides nationally consistent data for the 25-year period 1982–2007. Estimates here cover the contiguous 48 states. Separate estimates include Hawaii, Alaska, and the Caribbean.

Margins of error are reported for each NRI estimate and must be considered at all scales of analysis. The margin of error is used to construct the 95 percent confidence interval for the estimate. The lower bound of the interval is obtained by subtracting the margin of error from the estimate; the upper bound is obtained by adding the margin of error to the estimate. A 95 percent confidence interval means that in repeated samples from the same population, 95 percent of the time the true underlying population parameter will be contained within the lower and upper bounds of the interval. In the following tables, if there are instances where the margin of error is greater than or equal to the estimate, they are displayed in italics indicating that the confidence interval includes zero and the estimate should not be used.

 

Table 18. Water (Sheet & Rill) Erosion on Cropland, by Year, with Margins of Error
Year Million Tons per Year Tons per Acre per Year
1982 1,676.5
±13.3
4.0
±0.0
1987 1,488.2
±10.6
3.7
±0.0
1992 1,179.6
±9.4
3.1
±0.0
1997 1,039.5
±7.2
2.8
±0.0
2002 1,011.1
±12.7
2.8
±0.0
2007 959.9
±14.9
2.7
±0.0
Notes:
• Cropland includes cultivated and non-cultivated cropland.
• Estimated margins of error <.05 are shown as 0.0.

 

Table 19. Wind Erosion on Cropland, by Year, with Margins of Error
Year Million Tons per Year Tons per Acre per Year
1982 1,384.5
±28.9
3.3
±0.1
1987 1,304.5
±25.1
3.2
±0.1
1992 994.5
±24.2
2.6
±0.1
1997 846.4
±19.2
2.3
±0.0
2002 802.0
±28.4
2.2
±0.1
2007 765.1
±37.8
2.1
±0.1
Notes:
• Cropland includes cultivated and non-cultivated cropland.
• Estimated margins of error <.05 are shown as 0.0.

 

Table 20. Highly Erodible (HEL) Cropland and Non-Highly Erodible (Non-HEL) Cropland, by Year, in Millions of Acres, with Margins of Error
Year HEL Cropland Eroding At or Below Soil Loss Tolerance Rates HEL Cropland Eroding Above Soil Loss Tolerance Rates Total HEL Cropland Non-HEL Cropland Eroding At or Below Soil Loss Tolerance Rates Non-HEL Cropland Eroding Above Soil Loss Tolerance Rates Total Non-HEL Cropland
1982 41.4
±0.9
83.9
±1.0
125.3
±1.2
209.6
±1.7
84.7
±1.2
294.3
±1.8
1987 38.7
±0.9
79.0
±0.9
117.7
±1.2
209.3
±1.5
78.5
±1.0
287.8
±1.8
1992 41.2
±0.8
64.8
±1.0
106.0
±1.2
215.2
±1.5
60.3
±1.0
275.4
±1.8
1997 46.7
±1.0
57.9
±0.8
104.6
±1.2
220.8
±1.5
50.7
±0.8
271.5
±1.8
2002 45.1
±1.2
56.1
±1.5
101.2
±1.5
216.9
±1.9
49.0
±0.9
265.9
±2.1
2007 44.1
±1.3
53.6
±1.4
97.8
±1.7
213.7
±2.4
45.6
±1.5
259.3
±2.6
Notes:
• Cropland includes cultivated and non-cultivated cropland.

 

Table 21. Erosion on Highly Erodible (HEL) Cropland and Non-Highly Erodible (Non-HEL) Cropland, by Year, in Millions of Tons per Year, with Margins of Error
Year Highly Erodible (HEL) Cropland Non-Highly Erodible (Non-HEL) Cropland
Erosion on Land Eroding At or Below Soil Loss Tolerance Rates (T) Erosion on Land Eroding Above Soil Loss Tolerance Rates (T) Erosion on Land Eroding At or Below Soil Loss Tolerance Rates (T) Erosion on Land Eroding Above Soil Loss Tolerance Rates (T)
Erosion at T Erosion above T Total Erosion Erosion at T Erosion above T Total Erosion
1982 79.5
±2.1
344.1
±4.4
1,322.1
±22.9
1,666.2
±24.6
504.5
±4.5
388.6
±5.7
422.1
±9.1
810.7
±14.1
1987 74.3
±2.1
326.2
±4.0
1,146.6
±19.1
1,472.9
±21.1
484.4
±4.3
361.6
±4.8
399.5
±9.2
761.1
±13.2
1992 76.5
±2.2
267.6
±4.5
805.3
±21.2
1,072.9
±23.1
476.3
±3.5
277.3
±4.9
271.0
±4.4
548.4
±8.5
1997 87.7
±2.2
238.0
±3.7
640.4
±17.4
878.4
±19.4
455.4
±4.0
233.5
±3.9
230.9
±5.4
464.4
±8.4
2002 82.1
±3.4
232.5
±6.2
616.0
±29.4
848.5
±33.4
438.6
±5.8
226.3
±4.3
217.6
±8.2
443.9
±11.5
2007 78.7
±3.0
223.1
±6.7
595.1
±35.5
818.3
±39.7
418.3
±6.3
210.4
±6.9
199.3
±10.0
409.7
±16.3
Notes:
• Cropland includes cultivated and non-cultivated cropland.

Farm Production Region Results Tables

 

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