Soil quality is one of the most basic and perhaps least understood indicators of land health. Soil supports plant growth and represents the living reservoir that buffers the flows of water, nutrients, and energy through an ecosystem. The ongoing degradation of the earth’s soils by human activity, particularly agriculture, threatens human potential to feed a growing population. The annual global erosion amounts to about 36 billion tons, of which 10 billion are due to natural causes …showed first 75 words of 2833 total…

…showed last 75 words of 2833 total…D. Harvey, C. Resosudarmo, P. 1995. Environmental and economic costs of soil erosion and conservation benefits. Science v. 267 p. 1117-23. Smith, R. Smith T.M. 1998. Elements of ecology, fourth edition. Bennjamin/Cummings Publishing, Menlo Park, CA. Wilken, E. 1995. Assault of the earth. World Watch v. 8 p. 20-7. US News & World Report, 9/14/98. http.//www.usnews.soile.com. Dec. 2 1999. Yu, B. 1998. Rainfall erosivity and its estimation for Australia's tropics. Journal of Soil and Water Conservation v53 n2 p133 (8).