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Erosion

Erosion Research

Research continues to focus on the factors that control erosion rates and ways to lessen the impact of land use on soil productivity. New methods of soil conservation are continually being developed and tested to decrease the impact of soil erosion on crop production.

Conventional tillage techniques leave fields bare and exposed to the weather for extended periods of time, which leaves them vulnerable to erosion. Conservation tillage techniques are planting systems that employ reduced or minimum tillage and leave 30% or more of the field surface protected by crop residue after planting is done. Leaving crop residue protects the soil from the erosive effects of wind and rain. Direct drilling leaves the entire field undisturbed. Specialized machines poke holes through the crop residue, and seeds or plant starts are dropped directly into the holes. No-till planting causes more disturbance to the crop residue on the field. Using this technique, the farmer prepares a seedbed 2 in (5 cm) wide or less, leaving most of the surface of the field undisturbed and still covered with crop residues. Strip rotary tillage creates a wider seed bed, 4-8 in (10-20 cm) wide, but still leaves crop residue between the seed beds. Conservation tillage techniques are particularly effective at reducing erosion from farm lands; in some cases reducing erosion by as much as 90%.

Other erosion research is focused on the factors that control mass wasting, especially where it is hazardous to humans. Stabilization of slopes in high risk areas is an increasingly important topic of study, as more people populate these areas every day.

Resources

Books

Dixon, D. The Practical Geologist. New York: Simon & Schuster, 1992.

Hamblin, W.K., and E.H. Christiansen. Earth's Dynamic Systems. 9th ed. Upper Saddle River: Prentice Hall, 2001.

Leopold, L.B. A View of the River. Cambridge: Harvard University Press, 1994.

Woodhead, James A. Geology. Boston: Salem Press, 1999.

Periodicals

Reganold, J. P., R. K. Papendick, and J.F. Parr. "Sustainable Agriculture." Scientific American (June 1990): 112-120.


Clay Harris

KEY TERMS

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Bedrock

—The unweathered or partially weathered solid rock layer, which is exposed at the Earth's surface or covered by a thin mantle of soil or sediment.

Chemical weathering

—The decomposition and decay of Earth materials caused by chemical attack.

Deposition

—The accumulation of sediments after transport by wind, water, ice, or gravity.

Geomorphology

—The study of Earth's land forms and the processes that produce them.

Mechanical weathering

—The break up or disintegration of earth materials caused by the creation and widening of fractures. Also known as physical weathering.

Regolith

—A thin layer of sediment that covers most of the earth's surface. Erosion of the underlying solid rock surface produces this layer.

Slope stability

—The ability of the materials on a slope to resist mass wasting.

Soil productivity

—The ability of a soil to promote plant growth.

Surficial material

—Any type of loose Earth material, for example sediment or soil, found at the surface of Earth.

Additional topics

Science EncyclopediaScience & Philosophy: Ephemeris to Evolution - Historical BackgroundErosion - Sources Of Erosional Energy, Erosional Settings, Agents And Mechanisms Of Transport, Products And Impacts Of Erosion - Weathering, Vegetation, Climate, Surface material, Slope angle