[Functions of different cultivation modes in oasis agriculture on soil wind erosion control and soil moisture conservation].

During 2001-2002, the effects of different cultivation modes including winter irrigation and zero tillage, crop-grass intercropping, and early spring film mulching on sand entrainment, wind velocity gradient and soil moisture conservation were studied in the middle reaches of the Heihe River in the Hexi Corridor region. The results showed that all these modes could reduce soil wind erosion and halt sand entrainment to different degrees. Compared with the bare fields exposed by spring plowing, early spring film mulching could increase soil moisture storage by 35.6%. At present, spring plowing and sowing was a main factor responsible to the occurrence of sand storms and the increase in suspended dust content. Farmlands in the upper and middle reaches of the Heihe River generally produced a dust transport up to 4.8-6.0 million tons per year, which was higher than that of sandy desert in the same region. In the Hexi Corridor region, the suspended dust amount produced from 1 hm2 farmland was equivalent to that of 1.5 hm2 desert.