Shen Kai-Hui, Wei Shi-Guang, Li Lin, Chu Xiao-Xue, Zhong Jian-Jun, Zhou Jing-Gang, Zhao Yi
School of Life & Environmental Sciences, Guilin University of Electronic Technology, Guilin 541004, China.
Key Laboratory of Ecology of Rare and Endangered Species and Environmental Protection, Ministry of Education, Guangxi Normal University, Guilin 541006, China.
Huan Jing Ke Xue. 2024 Jan 8;45(1):323-334. doi: 10.13227/j.hjkx.202211142.
The aim of this study was to explore the carbon storage potential of karst forest soils in the Lijiang River Basin, reveal the spatial pattern of soil organic carbon (SOC), investigate the contributions and pathways of each driving factor to the spatial distribution of soil organic carbon, and provide a scientific basis for assessing the carbon cycle function of karst forests in the region. We employed structural equation modeling (SEM) and correlation analysis to investigate the spatial distribution characteristics of forest soil organic carbon in different basin sections (upper, middle, and lower reaches) and soil layers at different depths of the Lijiang River. Additionally, the direct and indirect ratios of each factor were quantified. The results showed that the overall soil layer of karst forest soils in the Lijiang River Basin was shallow, and soil organic carbon was phenoconcentric. The distribution of soil organic carbon content in different watershed sections was upstream > downstream > midstream, and the distribution of readily oxidizable carbon (ROC) and dissolved organic carbon (DOC) was consistent, whereas the distribution of microbial biomass carbon (MBC) was upstream > midstream > downstream. The contribution of various biotic and abiotic factors to the spatial distribution of soil organic carbon in karst forests in the watershed was different, and their contributions were ranked in descending order as:soil physicochemical factors > soil organic carbon active fraction > sample elevation > sample species diversity, with the total effects of 1.148, 0.574, 0.284, and -0.013, respectively. Among them, the sample site elevation had only an indirect effect on soil organic carbon, and the soil organic carbon active fraction had only a direct effect on soil organic carbon. Among the driving factors, total soil nitrogen, soil oxidizable organic carbon, sample site species richness, and soil soluble organic carbon could be used as important predictors of soil organic carbon content in karst forests in the Lijiang River Basin. Therefore, it is necessary to establish an effective eco-environmental protection mechanism covering the whole Lijiang River Basin, to reduce and control the impact of anthropogenic disturbances (especially in the middle urban section of the Lijiang River Basin), and to enhance and protect the species diversity of karst forests in the basin in order to improve soil physicochemical properties, improve and enhance the content of the soil organic carbon active fraction, and enhance the soil organic carbon stocks of karst forests in the Lijiang River Basin through other effective ways, as well as to promote the enhancement of the regional forest carbon sink function.
本研究旨在探讨漓江流域喀斯特森林土壤的碳储存潜力，揭示土壤有机碳（SOC）的空间格局，研究各驱动因素对土壤有机碳空间分布的贡献及途径，为评估该地区喀斯特森林的碳循环功能提供科学依据。我们采用结构方程模型（SEM）和相关性分析，研究了漓江不同流域段（上游、中游和下游）以及不同深度土层中森林土壤有机碳的空间分布特征。此外，还对各因素的直接和间接比例进行了量化。结果表明，漓江流域喀斯特森林土壤的整体土层较浅，土壤有机碳呈表聚性。不同流域段土壤有机碳含量的分布为上游>下游>中游，易氧化有机碳（ROC）和溶解有机碳（DOC）的分布一致，而微生物量碳（MBC）的分布为上游>中游>下游。流域内各种生物和非生物因素对喀斯特森林土壤有机碳空间分布的贡献不同，其贡献由大到小依次为：土壤理化因素>土壤有机碳活性组分>样地海拔>样地物种多样性，总效应分别为1.148、0.574、0.284和-0.013。其中，样地海拔对土壤有机碳仅有间接影响，土壤有机碳活性组分对土壤有机碳仅有直接影响。在驱动因素中，土壤全氮、土壤可氧化有机碳、样地物种丰富度和土壤可溶性有机碳可作为漓江流域喀斯特森林土壤有机碳含量的重要预测指标。因此，有必要建立覆盖整个漓江流域的有效生态环境保护机制，减少和控制人为干扰的影响（特别是在漓江流域城市中段），加强和保护流域内喀斯特森林的物种多样性，以改善土壤理化性质，提高和增强土壤有机碳活性组分的含量，并通过其他有效途径增强漓江流域喀斯特森林的土壤有机碳储量，促进区域森林碳汇功能的提升。
