科尔沁沙质草地沙漠化过程中土壤生物活性的变化

选择相邻地段的固定沙丘、半固定沙丘和流动沙丘为对象,研究了科尔沁西部沙质草地沙漠化过程中土壤微生物量、土壤酶活性和土壤养分的变化特征以及三者之间的相关关系.结果表明:土壤养分含量、土壤酶活性和微生物量均随土壤深度的增加而逐渐降低;沙漠化过程中土壤养分严重丧失,土壤微生物量碳、氮、磷,以及土壤脲酶、蛋白酶、蔗糖酶、磷酸单酯酶、脱氢酶、多酚氧化酶和硝酸还原酶的活性均随沙漠化程度的加剧而大幅度下降;土壤生物活性对土壤沙漠化比较敏感,在固定沙丘到半固定沙丘的转化过程中土壤生物活性下降最快;土壤微生物量、土壤酶活性以及土壤养分之间均存在显著的相关关系.

Changes of soil biological activity in desertification process of Horqin sandy grassland

With the adjacent plots of fixed, semi-fixed, and moving sand dunes in west Horqin sandy land as test objects, this paper studied the change characteristics of soil microbial biomass, enzyme activities and nutrients as well as the relationships among the three indices in the process of desertification. The results showed that soil nutrient contents, microbial biomass, and enzyme activities all decreased gradually with increasing soil depth. In the process of desertification, soil nutrient contents had a heavy loss, and soil microbial biomass C, N and P as well as the activities of urease, protease, saccharase, phosphatase, dehydrogenase, polyphenol oxidase, nitrate reductase decreased significantly. Soil biological activity was very sensitive to desertification, and its decrease was the quickest in the phase from fixed- to semi-fixed sand dune. There existed significant correlations among soil microbial biomass, enzyme activities and nutrient contents.