JLE

Science et changements planétaires / Sécheresse

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Érosion éolienne au Sahel et sécheresse Volume 5, issue 3, Septembre 1994

Author
CREGEPE Université de Caen, 14032 Caen cedex, France
  • Page(s) : 199-210
  • Published in: 1994

Interactions between wind erosion and drought work on three different scales: soil, by modifying its properties; medium (i.e. local and regional), through the disappearance of plant cover and resulting soil erosion and sand transport; and global, by the general increase in deflation and resulting dust injection into the atmosphere, further contributing to the desertification process. In the "wind-drought-soil" system, studying aerological factors makes it possible to determine the parameters of erosion which control aeolian degradation of soil. Drought, by altering the mechanical, hydric, chemical and mineralogical characteristics of soil, increases its susceptibility to wind erosion. The consequences of the drought / wind-erosion relationship on the local and regional scale are: disappearance or reduction of plant cover due to soil water loss; degradation of the upper soil horizons and outcropping of large, barren diricrusts; wind transport of sand-sheets with its en-suing increase in the erosion process. On a global scale, the interaction of drought and wind-erosion of soil on desert borders causes an increase in two wind-damage phenomena: sanding up, creating difficulties for human activity and land management, and increased dry haze worsening the already polluted atmosphere.