More efficient use of existing water resources and control of salinization are other effective tools for improving arid lands. New ways are being sought to use surface-water resources such as rain water harvesting or irrigating with seasonal runoff from adjacent highlands. New ways are also being sought to find and tap groundwater resources and to develop more effective ways of irrigating arid and semiarid lands. Research on the reclamation of deserts also is focusing on discovering proper crop rotation to protect the fragile soil, on understanding how sand-fixing plants can be adapted to local environments, and on how grazing lands and water resources can be developed effectively without being overused.
[Illustration: From wasteland to vineyard. Ground water and underground channels help this vineyard flourish on land reclaimed from desert pavement in China's Turpan Depression.]
If we are to stop and reverse the degradation of arid and semiarid lands, we must understand how and why the rates of climate change, population growth, and food production adversely affect these environments. The most effective intervention can come only from the wise use of the best earth-science information available.
Bagnold, R. A., 1941, The physics of blown sand and desert dunes: Methuen, London, 265 p. (A classic treatise concerning the origin and evolution of dunes.)
Breed, C. S., and others, 1979, Regional studies of sand seas, using Landsat (ERTS) imagery: _in_ McKee, E. D., ed., A study of global sand seas: U.S. Geological Survey Professional Paper 1052, p. 305-397. (A study of selected sand seas based on analysis of remote sensing images, surface wind summaries, and available literature.)
Cook, R. U., and Warren, Andrew, 1973, Geomorphology in deserts: University of California Press, Berkeley, California, 374 p. (Examines the nature of landforms, soils, and geomorphological processes in the world's deserts.)
Eigeland, Tor, and others, 1982, The desert realm: National Geographic Society, Washington, 304 p. (A well illustrated discussion of deserts of America, Africa, Asia, and Australia.)
Ericksen, G. E., 1983, The Chilean nitrate deposits: American Scientist, v. 71, p. 366-374. (A discussion of the origin of the Chilean nitrate deposits which has puzzled scientists for more than 100 years.)