江河源区高寒草地土壤微生物数量特征

采用土壤微生物的常规培养方法对青藏高原江河源区不同退化程度高寒草地土壤微生物的数量特征进行了分析。结果表明(1)土壤中微生物3大类群,及微生物总数在未退化高寒草地的数量大于退化高寒草地,差异显著(P<0.05),中度与重度退化草地间差异不显著(P>0.05);(2)分析地6个微生物生理类群中,硝化细菌、好气性固氮菌、嫌气性固氮菌、好气性纤维分解菌的数量随草地的退化而减少,未退化草地与退化草地间的数量差异显著(P<0.05),反硝化细菌、嫌气性纤维分解菌的数量则随草地退化而增加;(3)退化高寒草地土壤微生物数量以细菌占绝对优势,土壤微生物数量变化总体上反映了高寒草地退化的状况,但是与草地退化的关系应该结合地上植被、土壤环境进行综合分析。

Studies on soil microorganism numbers of different degraded alpine meadows in the headwater area of Yangtze and Yellow Rivers

The soil microorganism numbers of four different degraded alpine meadows(in the headwater area of the Yangtze and Yellow Rivers,China) were studied with the general method of culture mediums.The main results showed that:1) the normal meadow soil had more soil microorganism than the degraded meadows(light degraded,medium degraded,heavy degraded meadows),and the difference was significant(P<(0.05)),but the difference between the medium degraded meadow and the heavy degraded meadow was not significant (P>(0.05));2)six bacterial physiological groups were found out and the amount of nitrobacteria,aerobic-azotobacter,anaerobic azotobacter,aerobic cellulose decomposing bacteria tended to be decreased with the meadow degradation,then the difference between normal meadow and degraded meadow was significant (P<0.05).However,the amount of denitrifying bacteria and anaerobic cellulose decomposing bacteria were increased with the degradation degree;3)the variation of soil microorganism of different degraded meadows showed different degraded degree of alpine meadows in the headwater area of Yangtze and Yellow Rivers,but the relationship between soil microorganism and the process of alpine meadow degradation should be studied with the vegetation condition and circumstance of soils in the future.