Straw grids (one of which is shown above) and vegetation irrigated by water from the Yellow River stabilize dunes in this part of China’s Tengger Desert (shown below) and protect a nearby railroad from windblown sand.
Tengger Desert
Oases and farmlands in windy regions can be protected by planting tree fences or grass belts. Sand that manages to pass through the grass belts can be caught in strips of trees planted as wind breaks 50 to 100 meters apart adjacent to the belts. Small plots of trees may also be scattered inside oases to stabilize the area. On a much larger scale, a “Green Wall,” which will eventually stretch more than 5,700 kilometers in length, much longer than the famous Great Wall, is being planted in northeastern China to protect “sandy lands”—deserts believed to have been created by human activity.
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.
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.
Selected Readings
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.)
Gerster, Georg, 1960, Sahara-desert of destiny: Coward-McCann, New York, 302 p. (How plants, animals, and people survive in the Sahara.)
Greeley, Ronald, and Iversen, J. D., 1985, Wind as a geological process on Earth, Mars, Venus and Titan: Cambridge University Press, New York, 333 p. (Expands the classic work of Bagnold to discuss eolian processes in a planetary context. Describes the processes on all moons and terrestrial planets with atmospheres.)
Hare, F. K., 1983, Climate on the desert fringe: in Gardner, Ritz, and Scoging, Helen, eds., Mega-geomorphology: Clarendon Press, Oxford, p. 134-151. (The margins of many deserts are affected by tension between society and environment. This paper summarizes the climatology of arid zones.)
MacMahon, James A., 1985, Deserts: Alfred A. Knopf, Inc., New York, 640 p. (An Audubon Society Nature Guide to the deserts of the United States, and their inhabitants.)
McCauley, J. F., and others, 1984, Remote monitoring of processes that shape desert surfaces: The Desert Winds Project: U.S. Geological Survey Bulletin 1634, 19 p. (Describes a new study on collecting weather data from solar-powered data-collection platforms in deserts. The data are relayed by a GOES satellite to the USGS in Flagstaff, Arizona, and converted to graphic form.)
Meigs, Peveril, 1953, World distribution of arid and semi-arid homoclimates: in Reviews of research on arid zone hydrology: Paris, United Nations Educational, Scientific, and Cultural Organization, Arid Zone Programme-1, p. 203-209. (Classifies arid lands according to precipitation.)
Nelson, R., 1988, Dryland management: the desertification problem: Environmental Department Working Paper No. 8, Washington: World Bank, 42 p. (An excellent review of the present state of knowledge concerning desertification.)
Tolba, M. K., 1984, Desertification is stoppable: Arid Lands Newsletter No. 21, p. 2-9. (A discussion of the problems involved in preventing desertification and reclaiming arid lands.)
Walker, A.S., 1986, Eolian geomorphology: in Short, N.M., and Blair, R.W., eds., Geomorphology from space: a global overview of regional landforms: NASA SP-486, p. 447-520 (a brief review of desert processes).
Warren, A. and Agnew, C., 1988, An assessment of desertification and land degradation in arid and semi-arid areas: International Institute for Environment and Development, Drylands Programme, Paper 2, London: IIED, 103 p. (An evaluation of land degradation problems.)