Resource Inventory—Sheet, Rill and Wind Erosion

Abstract

ABSTRACT THE National Resource Inventories (NRI) carried out by the Soil Conservation Service in 1977 provide statistical data on sheet and rill erosion for all nonfederal land in the United States (excluding Alaska) and data on wind erosion in 10 Great Plain States. The data were ob-tained by visiting plots and randomly selected points to gather information for use in the Universal Soil Loss Equation and Wind Erosion Equation models. The NRI show that soil lost by sheet and rill erosion annually amounts to 3.5 billion metric tons (t). About one-half of this loss is from the 167-million-ha cropland base; the most sloping 26 percent contributes 79 percent of the cropland erosion. In 19 states and the Caribbean Area, estimated average annual cropland sheet and rill erosion exceeds 11.2 t/ha. In four states and the Caribbean Area the rate exceeds 22.4 t/ha. The 219 million ha of nonfederal pastureland and rangeland account for 1.4 billion metric tons of soil lost from sheet and rill erosion. The loss on nonfederal forest land is about 395 million t; the average annual rate is 2.6 t/ha, but the rate is six times higher on grazed than on nongrazed forest land. Soil lost by wind erosion, estimated for 209 million ha of land in 10 Great Plains States, annually amounts to 1.4 billion t. About 61 percent of this loss is from cropland and 38 percent is from rangeland. The estimated average annual rate of wind erosion on cropland exceeds 11.2 t/ha in three of the 10 states.