天山雪岭云杉林地土壤汞的分布特征及影响因素

Distribution characteristics and influencing factors of mercury on the soil profile of Picea Schrenkiana forest

土壤汞的空间分布及其影响因素是研究森林系统汞循环的基础与关键.为了了解天山雪岭云杉林地土壤汞的分布特征及影响因素,以天山雪岭云杉8 hm2林地动态监测样地为研究对象,分析了总汞在土壤剖面及空间上的分布特征,并利用路径分析探究了土壤总汞与土壤有机碳、海拔高度、郁闭度等的关系.研究表明,天山雪岭云杉林0-60 cm土壤总汞均值为(35.43±24.53)ng·g^(−1),主要集中在0-20 cm土层;样地内土壤总汞随土壤深度增加而降低,0-20 cm土壤总汞水平空间差异显著,表现出北高南低,沟壑高坡顶低的特点;土壤中有机碳与总汞相关最显著,海拔、郁闭度和雪岭云杉胸径、树高、冠幅等因素对土壤总汞空间分布影响并不显著,说明雪岭云杉林土壤总汞空间分布主要由有机碳决定.本研究可为天山森林土壤汞储量的研究提供数据参考,同时为更深入了解天山雪岭云杉森林汞的生物地球化学循环过程提供必要的基础.

The spatial distribution of soil mercury and its influencing factors are the basis and key to study the mercury cycle in forest system.In order to understand the distribution characteristics and influencing factors of soil mercury in the forest land of Picea schrenkiana,the dynamic monitoring sample plot of 8 hm2 forest land of Picea schrenkiana was taken as the research object.The distribution characteristics of total mercury in soil profile and space were analyzed,and the relationship between total mercury and soil organic carbon,altitude,canopy density was explored by using path analysis.The results showed that:(1)The mean value of total mercury in 0-60 cm soil of Picea schrenkiana forest was(35.43±24.53)ng·g^(−1),mainly concentrated in 0-20 cm soil layer;(2)the total mercury in soil decreased with the increase of soil depth,and the spatial difference of total mercury in 0-20 cm soil was significant,showing the characteristics of high in the north and low in the south,high in the gully and low in the top of the slope;(3)the organic carbon and total mercury in soil were most significantly correlated,with the altitude and canopy density The spatial distribution of soil total mercury was not significantly affected by the DBH,height and crown diameter of Picea schrenkiana,which indicated that the spatial distribution of soil total mercury in Picea schrenkiana forest was mainly determined by organic carbon.This study provided data references for the study of soil mercury reserves in the Tianshan forest,and a necessary basis for a deeper understanding of the biogeochemical cycle of mercury in the Tianshan Picea Schrenkiana Forest.