Change in soil microbial necromass in a broad-leaved evergreen forest along altitudinal gradient in Yongde Snow Mountain,southwest Yunnan
Microbial necromass plays an important role in the formation of soil organic carbon(SOC).However,the change of microbial necromass along altitudinal gradient remains unclear.In this study,we analyzed the differ-ences of soil physicochemical properties,microbial necromass(topsoil 0-20 cm),and stand characteristics along an altitudinal gradient(1200,1700,and 2200 m)in a broad-leaved evergreen forest in Yongde Snow Mountain,Yunnan Province,aiming to reveal the regulatory mechanism of microbial necromass accumulation along the altitu-dinal gradient.The results showed that microbial necromass was 15.36 g·kg-1 in the broad-leaved evergreen forest and that its contribution to SOC was 24.09％.The contribution of fungal necromass to SOC(20.36％)was higher than that of bacterial necromass(3.73％).Fungal,bacterial,and microbial necromass increased significantly with increasing altitude.There was no significant difference in the contribution of fungal and microbial necromass to SOC along the altitudinal gradient.In addition,woody species composition showed significant effects on fungal and mi-crobial necromass.Microbial necromass increased with increasing soil nutrients,but increased significantly with de-creasing woody species richness.Furthermore,higher SOC,soil total nitrogen,soil available nitrogen,and soil wa-ter content,and lower soil pH could promote the accumulation of microbial necromass.Soil nutrient,altitude,and woody species diversity were the important factors affecting microbial necromass.Therefore,altitude promoted the accumulation of microbial necromass but did not increase its contribution to SOC.
amino sugarfungal necromassbacterial necromasssoil organic carbonwoody species diversityal-titude
徐凡迪、杨玉春、陈燕旋、李聪、吴疆翀、Wang Tongli、李帅锋、苏建荣
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中国林业科学研究院高原林业研究所,昆明 650224
临沧市林业科学院,云南临沧 677000
Faculty of Forestry,The Uni-versity of British Columbia,Vancouver,BC Canada,V6T1Z4
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