Microbial community and soil enzyme activities along an altitudinal gradient in Sejila mountains

Abstract:

[Objective] This study tried to find the key factor which affected the soil microbial communities and enzyme activities along an altitudinal gradient in forest ecosystem in Sejila mountains. [Methods] This study tested six soil enzyme activities (β-glucosidase, phenol oxidase, protease, L-asparaginase, urease and acid phosphatase) and soil microbial communities structures (bacteria, fungi, gram-positive bacteria, gram-negative bacteria and actinomycete). [Results] Soil physicochemical properties such as moisture, TOC, TN, C/N and pH had no significant changes along the altitudinal gradient. Moreover, soil enzyme activities such as β-glucosidase, phenol oxidase, protease, L-asparaginase and acid phosphatase had no significant change along the altitudinal gradient. However, bacteria, fungi, gram-positive bacteria, gram-negative bacteria and actinomycete biomass all showed a mid-domain effect along the altitudinal gradient, which reached higher values at 3 900 and 4 000 ms.a.l. Person correlation analysis showed that pH was the key factor structuring microbial communities, yet mean annual temperature had no significant correlation with microbial communities and enzyme activities. Instead, soil physicochemical properties such as TOC, TN, WSOC and WSON were key factors in enzyme activities. [Conclusion] These results suggested that elevational gradients had an important influence on soil microbial communities, but not on soil physicochemical factors and soil enzyme activities.

Key words:soil microorganism, soil enzyme activities, Tibet Plateau, forest ecosystem