黄河源区高寒退化草地鼠丘对土壤风蚀作用的影响

Effects of Rodent mounds on Soil Wind Erosion in Alpine Degraded Grassland of the Yellow River Source Zone

为阐明高寒草地鼠丘土壤风蚀特征和规律,以青海省河南县退化草地区域内的鼠丘为研究对象,采用野外人工模拟风力侵蚀试验方法,对不同风速条件下鼠丘大小、形状、土壤含水量及含根量对土壤风蚀作用的影响进行了研究。结果表明:高寒草地鼠丘土壤的风蚀量随着风速的增加而增加,风速从6 m/s逐步增加到12 m/s时,鼠丘土壤流失量增加1.22~1.79倍,且土壤流失量与风速和鼠丘大小呈正比。同等条件下,鼠丘形状不同时其土壤风蚀量也不同,3种类型的鼠丘土壤风蚀量的大小依次为半球型>凸凹型>平缓型,其中半球型鼠丘土壤流失量比凸凹型和平缓型鼠丘分别增加了35.5%,92.6%,且侵蚀前5 min是土壤风蚀速率最敏感的时期。土壤流失量随植被根系和土壤含水量的增加而减小,说明鼠丘内的植被根系以及土壤含水量对土壤风蚀量具有抑制作用,是鼠丘土壤风蚀的重要抗蚀因子。

In order to clarify the characteristics and rules of rodent mound soil under wind erosion in alpine grasslands of the Yellow River Source Zone,the rodent mounds in the degraded grasslands area of Henan County in Qinghai Province was taken as the research object.The effects of the wind on the size,shape,soil water content and root content due to wind erosion on rodent mound soil under different wind speeds were carried out by field artificial simulated wind erosion tests.The results showed that the amount of soil wind erosion increased with the increase of wind speed on rodent mounds in alpine grasslands.The amount of soil loss was proportional to wind speed and the size of the rodent mound,and it increased 1.22~1.79 times when wind speed gradually increased from 6 m/s to 12 m/s.The amount of soil loss and the amount of soil wind erosion is different with the shape of rodent mounds under the same conditions.The degree of wind erosion on each of the three shapes of rodent mounds is in the order of hemispherical shape>concave-convex shape>flat shape,and the amount of soil loss of the hemispherical mounds was 35.5%and 92.6%higher than that of the concave-convex mounds and flat mounds respectively.The most sensitive period of the soil wind erosion rate on rodent mounds is the first 5 minutes.The amount of soil loss decreased with the increase of vegetation roots and soil water content,which indicates that these factors have an inhibitory effect on the amount of soil wind erosion,and they are important anti-erosion factors of the rodent mounds.