Seasonal dynamics of soil microbes and their relationship with soil physicochemical factors in alpine meadow in Maqu of Gansu

The seasonal dynamics of different soil microbes and their relationships with soil physicochemical factors were studied. The soil samples were taken from six sampling points of alpine meadow located in Maqu of Gansu. The results showed that soil bacteria occupied absolute advantage among soil microbes. Seasonal variation had a great influence on soil microbial activities. Soil microbes and soil physicochemical factors had close relationship. The peak value of bacteria quantity in soil appeared in April. Actinomycetes number decreased gradually from spring to autumn, while activities of fungi were stable. Ammonifier and nitrobacteria had more activities in April and October; denitrifier had more in July; and amounts of aerobic nitrogenfixing bacteria and aerobic cellulose decomposer were more in January. The results of main composition analysis of soil microbial quantity showed that aerobic nitrogenfixing bacteria and aerobic cellulose decomposer offered more contribution to soil fertility. The results of canonical correlation analysis showed that there was only one group of canonical variable correlation, which was caused by bacteria, fungi, ammonifier, denitrifier and soil pH value, conductivity, nitrate nitrogen, ammoniacal nitrogen and total phosphorus.