Page 116 - Soil Degradation, Conservation and Remediation

104 4 Wind Erosion

Fig. 4.1 Severe wind erosion may lead to desertification (Photo courtesy of USDA-NRCS)

be accelerated more than a factor of 10 by cultivation, a factor of 1.14 by overgrazing,
and a factor of 22.8 by overcutting (Dong et al. 1987; Hu et al. 1991; Liu et al. 1992).
137
Yan (2000) estimated using Cs measurements that in Gonghe Basin of Qinghai
Province, China, the annual wind erosion rate of dry farmland is three times greater
than that of adjacent grassland, and that during cultivation wind erosion may
increase to a factor of 5–8 over the adjacent grassland. As a whole, the increased
wind erosion caused by human factors on an average accounts for approximately
78 % of the total wind erosion (Liu et al. 1992; Wang and Wu 1999).

4.2 Effects of Wind Erosion

In the USA, wind erosion damages from 0.4 to 6 M ha of land annually, and about
2 M ha is moderately to severely damaged each year (Gregory and Borrelli 1986).
Wind erosion not only removes soil but also damages crops, buildings, fences, and
highways. Wind erosion removes the lighter, less dense soil constituents such as
organic matter, clays, and silts. It causes loss of the most fertile part of the soil and
significantly reduces soil productivity. If reversion measures are not taken and
wind erosion continues for long, it may ultimately lead to desertification (Fig. 4.1).
Lyles (1975) estimated that top soil loss from wind erosion causes annual yield
reductions of about 340,000 bushels of wheat and 545,000 bushels of grain sorghum
on 0.5 M ha of sandy soils in southwestern Kansas, USA. Blowing soil impacting
plants can also reduce seedling survival and growth, depress crop yields, lower
the marketability of vegetable crops, increase the susceptibility of plants to certain