Reclamation of Chemically Degraded Soils

Abstract

Land degradation has become a major global concern in recent years as a result of increasing demands on the land for food production and waste disposal. Man is learning that the resiliency of soil is finite and that soil degradation is not easily reversed, if ever. The focus of land degradation in this century has been on soil erosion as increasing areas of forest, grassland, and wetland have been cleared for crop production. Soil erosion represents the most complete form of land degradation—the removal of the soil resource itself—and eroded sediment deposited on adjacent lands and drainageways can lead to further degradation. In recent years, the contribution of soil erosion to global carbon emissions has been recognized as equally important to that of deforestation and fossil fuel burning (Tans et al., 1990). Soil erosion remains the focus of conservation efforts in the developed world and many of the resources of agencies like the U.S. Soil Conservation Service are devoted to reducing soil loss to “tolerable” limits (Follett and Stewart, 1985). Other developed countries have similar programs. Soil erosion from land clearing and improper management in the developing world—and in particular those of the subtropics and tropics— has reached massive proportions and is the subject of worldwide attention.