ABSTRACT:
The role of natural plant cover in soil protection after forest harvesting and mechanical site preparation was studied from 1981 to 1984 in two contrasting physiographic provinces of southern Arkansas. Clearcutting with mechanical site preparation disturbed groundcover in virtually the same manner and to the same degree at both locations. Soil was exposed on about 47% of the surface area of three cleared watersheds in the Gulf Coastal Plain and on 53% of three watersheds in the Athens Plateau. Litter was left in place on about 38% of the area at both locations. Small plants, stumps, bark, and other wood debris provided a lesser amount of cover. Invading grasses and herbaceous plants quickly revegetated all watersheds during the first post-harvest year; exposed soil declined to only 5% of the watershed areas. Bare soil was further reduced the second year, to less than 1% on the Coastal Plain watersheds and to 2% on the Athens Plateau watersheds. Discharge-weighted sediment concentrations in watershed runoff declined from 208 ppm the first post-harvest year to 14 ppm the second year in the Gulf Coastal Plain. Mean concentrations for the three Athens Plateau watersheds increased slightly from 122 ppm to 129 ppm during the second year because of two extremely large storms; but even there concentrations from two of the three watersheds were less than the first-year levels.
Footnotes
R. Scott Beasley is a professor and Alfredo B. Granillo is a research specialist with the Department of Forest Resources, Arkansas Agricultural Experiment Station, University of Arkansas at Monticello, Monticello, 71655. The study is part of the South Central Region Water Quality Project. Funding and assistance provided by the Arkansas Agricultural Experiment Station, U.S. Forest Service-Southern Forest Experiment Station, Arkansas Forestry Commission, Arkansas Department of Pollution Control and Ecology, Arkansas Water Resources Research Center, Ross Foundation, International Paper Company, Weyerhaeuser Company, Arkansas Kraft Corporation, Deltic Farm and Timber Company, Potlatch Corporation, and Bearden Lumber Company. Published with the approval of the Director, Arkansas Agricultural Experiment Station.
- Copyright 1985 by the Soil and Water Conservation Society
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