Over seventy years after the Dust Bowl ended, wind erosion continues to threaten the sustainability of our nations' natural resources. As recently as the spring of 1996, wind erosion severely damaged agricultural land throughout the Great Plains. On cropland, about 70 million hectares (171.8 million acres) are eroded by wind and water at rates that exceed twice the tolerance level for sustainable production (USDA, 1989). On average, wind erosion is responsible for about 40 percent of this loss (Hagen, 1994), and can increase markedly in drought years (Hagen and Woodruff, 1973). In the United States, wind erosion is the dominant problem on about 30 million hectares (73.6 million acres) and moderately to severely damages approximately 2 million hectares (4.9 million acres) annually (USDA, 1965). According to the 1992 National Resources Inventory (NRI), the estimated annual soil loss from wind erosion on nonfederal rural land in the United States was 2.5 tons per acre per year (SCS-USDA, 1994). This number is a decrease from 3.3 tons per acre per year in the 1982 NRI. However much of this reduction was a result of enrollment of land classified as highly erodible in the Conservation Reserve Program (CRP). The CRP enrollment for much of this acreage is scheduled to retire within the next few years.
Wind erosion physically removes the lighter, less dense soil constituents such as organic matter, clays, and silts. Thus it removes the most fertile part of the soil and lowers soil productivity (Lyles, 1975). Lyles (1975) estimated that top soil loss from wind erosion causes annual yield reductions of 339,000 bushels of wheat and 543,000 bushels of grain sorghum on 0.5 million hectares (1.2 million acres) of sandy soils in southwestern Kansas. This loss in productivity has been masked or compensated for over the years by improved crop varieties and increased fertilization. Thus wind erosion reduces potential soil productivity and increases economic costs. Blowing soil impacting plants can also reduce seedling survival and growth, depress crop yields, lower the marketability of vegetable crops, increase the susceptibility of plants to certain types of stress, including diseases, and contribute to transmission to some plant pathogens (Armbrust, 1982 and 1984; Claflin, et al., 1973; Michels et al., 1995). In the long run, the cost of wind erosion control practices can offset the cost of replanting a blown out crop. Some soil from damaged land enters suspension and becomes part of the atmospheric dust load. Dust obscures visibility and pollutes the air, it fills road ditches where it can impact water quality, it causes automobile accidents, fouls machinery, and imperils animal and human health (Skidmore, 1988). In Seward County Kansas alone the state highway department spent over $15,000 in 1996 to remove 965 tons of sand from 500 feet of highway and ditch (Tri-County Area Proposal for EQIP, unpublished report). Wind erosion is a threat to the sustainability of the land as well as the viability and quality of life for rural as well as urban communities. Wind erosion in the United States is most widespread on agricultural land in the Great Plains states. Wind erosion is also a serious problem on cultivated organic soils, sandy coastal areas, alluvial soils along river bottoms, and other areas in the United States. In addition it is a major cause of soil degradation in arid and semiarid areas world wide.
LITERATURE CITED | DUST BOWL PHOTOGRAPHY |