在典型草原放牧退化过程中土壤环境质量的变化研究

A Study on the Change of Soil Environment Character in the Process of Degradation for Typical Steppe

在2001年5月～9月研究了三个不同退化强度草原群落的土壤含水量、有机质含量、全磷古量的差异及其季节变化特征，结果表明，春季和秋季未退化群落土壤含水量高于其他两个群落，夏季未退化群落含水量最低，不同群落土壤有机质和全磷含量大小顺序均为，未退化群落〉中度退化群落〉重度退化群落，方差分析指出中度退化群落与未退化群落土壤有机质在0～10cm土层处差异显著。而重度退化群落与中度退化群落土壤有机质在10～20cm土层处差异显著．三种群落全磷含最在0～10cm层次都没有显著差异，但在10～20cm和20～40cm层次上，未退化群落与中度退化群落、重度退化群落之间都存在极显著差异，而中度与量度退化群落之间差异不显著。

The water content, the contents of organic substance and total phosphorus of soil were measured for three different degraded degree communities from May to September in 2001. The result shows that the water content of soil in non-degraded community was higher than that in May and September, but was the lowest in July. The orders of the content of the organic substance, the content of total phosphorus of soil were： non-degraded community〉moderately degraded community〉heavily degraded community,respectively. For the contents of organic substance between the moderately degraded community and non-degraded community at 0～ 10 cm soil layer, between the moderately degraded community and the heavily degraded community at 10～20 cm soil layer, there were remarkable difference. The content of total phosphorus of soil did not exist remarkable difference among three different communities at 0～10 cm soil layer. At 10～20 cm and 20～40 cm soil layers, there were remarkable difference between non-degraded community and the other two degraded community,but there was no remarkable difference between the moderately degraded and the heavily degraded communities.