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Drought - Drought Management

soil water climate plants

Because drought is a natural phenomenon, it cannot be eradicated. Consequently, methods to mitigate its devastating effects are crucial. Crop and soil management practices can increase the amount of water stored within a plant's root zone. For example, contour plowing and terracing decreases the steepness of a hillside slope and thus, reduces the amount and velocity of water runoff. Vegetation protects the soil from the impact of raindrops, which causes both erosion and soil crusting (hardening of the soil surface that prevents rain from percolating into the soil where it is stored). Both living plants and crop residues left by minimum tillage reduce soil crusting so the soil remains permeable and can absorb rainfall.

Other farming practices that lessen the impact of drought on crop production include strip cropping, windbreaks, and irrigation. Windbreaks or shelterbelts are strips of land planted with shrubs and trees perpendicular to the prevailing winds. Windbreaks prevent soil, with its moisture-retaining properties, from being blown away by wind. Plants can also be specifically bred to adapt to the effects of weather extremes. For example, shorter plants encounter less wind and better withstand turbulent weather. Plants with crinkled leaves create small pockets of still air that slow evaporation.

From a social standpoint, drought severity is influenced by the vulnerability of an area or population to its effects. Vulnerability is a product of the demand for water, the age and health of the population affected by the drought, and the efficiency of water supply and energy supply systems. Drought's effects are more pronounced in areas that have lost wetlands that recharge aquifers, are dependent on agriculture, have low existing food stocks, or whose governments have not developed drought-response mechanisms.

Resources

Books

Climate Change 2001: Impacts, Adaptation and Vulnerability. Intergovernmental Panel on Climate Change, 2001.

Defreitas, Stan. The Water-Thrifty Garden. Dallas: Taylor Publishing Company, 1993.

White, Donald A., ed. Drought: A Global Assessment. New York: Routledge Publishers, 2000.


Karen Marshall

KEY TERMS

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Aquifer

—A formation of soil or rock that holds water underground.

Arid climate

—A climate that receives less than 10 in (25 cm) of annual precipitation and generally requires irrigation for agriculture.

Precipitation

—Water particles that are condensed from the atmosphere and fall to the ground as rain, dew, hail or snow.

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