放牧强度对土壤水分影响的对应分析

为了解不同放牧利用强度对荒漠草原土壤水分含量的影响，采用随机区组设计，研究轻度（LG）、中度（MG）、重度（HG）放牧对短花针茅荒漠草原土壤水分含量的影响。不同放牧强度的载畜率分别为O．93（LG）、1．82（MG）、2．71（HG）sheep／（hm^2half year），放牧羊只数分别为4、8、12只，放牧期为6个月／年。采用对应分析法比较不同放牧强度下近地表层0～10cm、10～20cm、20～30cm土壤的水分含量。结果表明，不同放牧梯度条件下，土壤含水量总体变化规律为LG〉CK〉MG〉HG．不同土层土壤含水量总体变化规律为0~10cm〉20-30cm〉10-20cm。各放牧强度对总特征值贡献率大小趋势为CK〉MG〉HG〉LG。随着放牧强度的增加，土壤含水量差异明显且呈梯度下降趋势。0-10cm土层土壤含水量受放牧强度的影响最大，其次为10～20cm和20～30cm土层．

Correspondence Analysis on Effect of Grazing Intensity on Soil Moisture

In order to investigate the effect of grazing intensity on soil moisture in desert grassland, the randomized block design method and correspondence analysis method were used to study the influence of lightly grazing （LG）, moderate grazing （MG） and highly grazing （HG） on soil moisture in Stipa breviflora desert grassland. The stocking rate of different grazing intensity were 0.93 （LG）, 1.82 （MG） and 2.71 （HG） sheep/（hm^2·half year）, and the number of grazing sheep was 4 （LG）, 8 （MG） and 12 （HG）, respectively. The grazing period was six months per year. The results showed that in different grazing intensity, the general change law of soil moisture was LG〉CK〉MG〉HG, and that of the soil moisture in different soillayer was 0-10 cm〉20-30 cm〉10-20 cm. The contribution rate of different grazing intensity on total characteristic value contribution rate was CK〉MG〉HG〉LG. With the increase of grazing intensity, the changes of soil moisture differences showed an obviously gradient descent tendency. The grazing intensity had the greatest impact on soil moisture of 0-10 cm soillayer, followed by 10-20 cm and 20-30 cm.