The Seasonal Dynamics Of Alpine Meadow Soil Microorganisms And The Response From Grassland Degradation In The Area Of Three River Source

1.Total number of microorganisms is much different among different types of grassland,but among the microorganisms,the number of bacteria is the highest (98.41%-93.12%),then followed by actinomycete(6.82%-1.44%),fungi is lowest.The season dynamics of bacteria and actinomycetes is in substantial agreement,the quantity increases then decreases regularly with change of season,but the fungi quantity is high in early stage and telophase of growing season and low in growing peak season.On the whole,The order of bacteria quantity is the reconstruction meadow＞residual meadow＞serious degenerated meadow;the order of fungi quantity is serious degenerated meadow＞the man-power restores the reconstruction meadow＞residual meadow;the order of actinomycete quantity is that residual meadow＞serious degenerated meadow＞the man-power restores the reconstruction meadow.2.The seasonal dynamics of soil protease activities in three types of grasslands is similar, With season changing the total soil protease activity presents the increased tendency,reachs highest in June and then decreases.The soil protease activity in residual meadow and the man-power restores the reconstruction meadow in significant higher than that in serious degenerated meadow.3.The soil protease activity in different types of grassland is extremely significantly positively correlated with total N.The correlation is most significant between soil protease activity that in residual meadow and soil microorganisms or the physical and chemical property.4.Among the whole growing season,the content of soil microbial biomass C in residual meadow is the most,less in the man-power restores the reconstruction meadow,and the least in serious degenerated meadow.The difference is not significant among them.What's more,the the seasonal dynamics of microbial biomass C is different among three types of grassland.The content of soil biomass C in residual meadow is the highest in May(925.47 mgC/kg),then decreasing,lowest in Auguest(550.30 mgC/kg),and increasd in September.The seasonal change is not obvious in other types of grassland.5.Among the whole growing season,the content of soil microbial biomass N in residual meadow is the most,it is significantly higher than that in serious degenerated meadow and the man-power restores the reconstruction meadow;the seasonal dynamics of microbial biomass N is same in different types of grassland.It increases rapidly in early days of growing season,and decreases rapidly in growing peak season,but increased gradually in telophase of growing season.6.The change of SON content in whole growing season in the same.,residual meadow＞the man-power restores the reconstruction meadow＞serious degenerated meadow,and the difference among them is significant.The man-power restorations can significantly increase the content of SON.Bue the seasonal dynamics of SON is different among three types of grassland.7.The soil microbial biomass and SON in different types of grassland have a certain degree positively correlation with total soil microorganisms,the microbial biomass N,SON in the man-power restores the reconstruction meadow and the SON in residual meadow are all extremely significantly positively correlated with total soil microorganisms;the soil microbial biomass N in residual meadow is extremely significantly positively correlatede with total N,that in man-power restores the reconstruction meadow is significantly positively correlatede.The microbial biomas C and microbial biomas N all have a certain degree positively correlation with water content;the SON has no significant correlation with microbial biomas C and microbial biomas and N.