科尔沁沙地不同风沙土的风蚀特征

通过风洞实验，研究了科尔沁沙地两种典型风沙土的风蚀特征。流动沙丘土样和农田土样的风蚀率随风速的增加均呈幂函数关系增长。风干的农田土样在风速3．7m／s时开始出现风蚀现象，但流沙土样的临界起沙风速是4．3m／s。在低风速段．农田土样的风蚀率大于流沙土样，但当风速增加到大约5．7m／s以上时，流沙土样的风蚀率开始大于农田土样，并且差值随风速的增加而加大。两种土样的风蚀率随土样含水率的增加呈负幂函数关系迅速减小。但流沙土样风蚀率的减小要比农田土样更迅速。流沙土样的临界起沙风速随含水量的增加呈线性关系增长，而农田土样的临界起沙风速随含水量的增加呈二次幂函数关系增长。两种风沙土在风蚀特征方面的差异，主要是由质地不同引起的。增加土壤含水量，是本地区风季减小风蚀的有效方法。

Wind Erosion Characteristics of Aeolian Soils in Horqin Sandy Land

Erosion characteristics of two kinds of typical aeolian soils in Horqin Sandy Land were studied using portable wind tunnel. Results show that soil loss rates of flowing sand and farmland samples increase in power function with increasing of wind velocity. The threshold wind velocity of air-dried farmland sample is about 3.7 m/s, while the velocity of flowing sand is about 4.3 m/s. The soil loss rate of farmland sample is larger than flowing sand sample in a range of a lower wind velocity, but soil loss rate of flowing sand sample is larger than that of farmland sample when wind velocity is more than 5.7 m/s. In addition, the difference between the soil loss rates increases with increasing of wind velocity. Soil loss rate decreases in power function with increasing of soil water moisture. Anyway, loss rate of flowing sandy sample decreases more rapidly than that of farmland sample. Threshold wind velocity of flowing sand sample linearly increases with increasing of soil water moisture, while the velocity of farmland sample increases in quadratic equation with increasing of soil moisture. The difference of wind erosion characteristics of the soils is attributed to different properties of the soils. Increasing of soil water moisture can efficiently decrease wind erosion in the region in erosion duration.