黑河中游湿地不同植物群落土壤有机碳分布及影响因素

湿地是全球碳循环重要组成部分之一,具有独特的生态环境效应和功能,对调节全球气候变化具有重要作用。本研究以黑河中游湿地为研究对象,基于实地采样数据、利用植物群落排序和结构方程模型等方法,分析不同植物群落土壤有机碳差异及影响因素。结果表明:湿地不同植物群落间土壤有机碳存在显著差异(P<0.05),土壤有机碳含量在3.56~4.30 g·kg^-1,呈现明显的表聚现象;土壤有机碳主要受容重、pH、土壤全氮、土壤水分、土壤速效氮、土壤盐分、优势物种盖度、总多度、总盖度、非禾本科草本盖度多种因素的影响,表明造成土壤有机碳变化的因素较为复杂;土壤理化性质对土壤有机碳变化的贡献为0.55,植物群落特征对土壤有机碳变化的贡献为0.22,表明在黑河中游造成各植物群落土壤有机碳变化的主要原因是土壤理化性质差异;土壤理化性质对土壤有机碳的影响有两种不同路径,一是土壤理化性质对土壤有机碳的直接影响,二是pH、盐分通过影响总多度从而影响土壤有机碳,表明在土壤有机碳变化的过程中,不仅仅有各影响因素单纯的直接作用,也有影响因素之间的间接作用。该研究结果对干旱区湿地土壤有机碳固存具有一定的参考价值。

Soil organic carbon and its influencing factors on the different plant communities in the middle reaches of the Heihe River wetland

Wetlands are one of the important components of the global carbon cycle.They have unique ecological and environmental effects and functions and play an important role in regulating global climate change.In this paper,a wetland in the middle reaches of Heihe River was taken as the research object.Based on field sampling data,plant community sequencing,and structural equation modeling,the soil organic carbon differences and influencing factors of the different plant communities were analyzed.The results showed that there were significant differences in soil organic carbon among the different plant communities in wetland(P<0.05),and the soil organic carbon content ranged from 3.56~4.30 g·kg^-1,showing obvious surface aggregation.Soil organic carbon is mainly affected by bulk density,pH,soil total nitrogen,soil moisture,soil available nitrogen,soil salinity,dominant species coverage,total abundance,total coverage,and forb coverage.The contribution of soil physical and chemical properties to soil organic carbon change was 0.55,while the contribution of plant community characteristics to soil organic carbon change was 0.22,indicating that the main reason for soil organic carbon change in plant communities in the middle reaches of Heihe River was the difference in soil physical and chemical properties.The influence of soil physical and chemical properties of soil organic carbon took two different paths:1)the soil directly affects the physical and chemical properties of soil organic carbon and 2)pH and salt influence the total soil organic carbon abundance.These results show that soil organic carbon change is not the result of a simple direct effect as various influencing factors have indirect effects.The results of this study have certain reference value for soil organic carbon sequestration in wetlands of arid areas.