退化高寒草甸土壤微生物及酶活性特征

Characteristics of soil microbes and enzyme activities in different degraded alpine meadows

采用Biolog等方法,分析不同退化程度(未退化ND、轻度退化LD、中度退化MD、重度退化SD和黑土滩ED)高寒草甸0~10和10~20 cm土层土壤微生物量碳氮、碳代谢指纹和酶活性.结果表明:所有草甸土壤微生物量、多样性指数和蔗糖酶活性在0~10 cm土层均显著高于10~20 cm土层,0~10 cm土层脲酶活性则显著低于10~20 cm土层.土壤微生物量C/N随草地退化程度加重显著降低.0~10 cm土层,ND和LD微生物量碳、氮均显著高于其他草地,MD、SD和ED微生物量碳无显著差异,MD微生物量氮显著低于其他草地;平均颜色变化率(AWCD)和Mc Intosh指数(U)随草地退化程度加重曲线下降,ND与MD间差异显著,其他草地间无显著差异;Shannon指数(H)和Simpson指数(D)在不同草地间均无显著差异;MD和SD脲酶活性最高,ED磷酸酶和蔗糖酶活性最低,与其他草地相比均差异显著.10~20 cm土层,ND和LD微生物量碳显著高于其他草地,MD、SD和ED间无显著差异,LD和ED微生物量氮显著高于其他草地,ND和SD间差异不显著;MD碳代谢指数最低,与LD和SD相比差异显著,ND和LD的AWCD和U指数均显著高于ED,H指数和D指数在ND、LD、SD和ED间差异不显著;ND和MD脲酶活性显著高于其他草地,LD、SD和ED间无显著差异;MD磷酸酶活性最高,与LD、SD和ED相比差异显著;MD蔗糖酶活性显著低于其他草地,ND、LD、SD和ED间差异不显著.不同退化程度高寒草地的地下生物量均与微生物量、碳代谢指数和磷酸酶呈显著正相关;脲酶与微生物量氮、H指数和D指数呈显著负相关.

Soil microbial biomass C and N,microbial diversities and enzyme activity in 0-10 cm and 10-20 cm soil layers of different degraded grasslands（non-degradation,ND;light degradation,LD;moderate degradation,MD;sever degradation,SD;and black soil beach,ED） were measured by Biolog and other methods.The results showed that：1） There were significant differences between 0-10 cm and 10-20 cm soil layers in soil microbial biomass,diversities and invertase activities in all grasslands.2） The ratio of soil microbial biomass C to N decreased significantly with the grassland degradation.In the 0-10 cm soil layer,microbial biomass C and N in ND and LD were significantly higher than that in MD,SD and ED.Among the latter three kinds of grasslands,there was no difference for microbial biomass C,but microbial biomass N was lower in MD than in the other grasslands.The average color change rate（AWCD） and Mc Intosh Index（U） also decreased with grassland degradation,but only the reduction from ND to MD was significant.There were no differences among all grasslands for Shannon index（H） and Simpson Index（D）.The urease activity was highest in MD and SD,and the activity of phosphatase and invertase was lowest in ED.In the 10-20 cm soil layer,microbial biomass C in ND and LD were significantly higher than that in the other grasslands.Microbial biomass N in LD and ED were significantly higher than that in the other grasslands.Carbon metabolism index in MD was significantly lower than that in LD and SD.AWCD and U index in ND and LD were significantly higher than that in ED.H index and D index showed no difference among different grasslands.The urease activity in ND and MD was significantly higher than that in the other grasslands.The phosphatase activity was highest in MD,and the invertase activity was lowest in MD.3） The belowground biomass was significantly positively correlated with microbial biomass,carbon metabolic index and phosphatase activity,and the urease activity was negatively correlated with microbial biomass N,H index and D index.