水力侵蚀对土壤碳循环及土壤微生物多样性影响的研究进展

[目的] 针对水力侵蚀对土壤碳循环"源汇"效应争议,综述水力侵蚀对土壤有机碳矿化作用和土壤微生物多样性的影响机制,提出未来定量研究的方向与注意事项。[方法] 在提出水力侵蚀对土壤碳循环"源"汇"效应概念和理论的基础上,分析现阶段研究中水力侵蚀对土壤碳循环"源汇"效应争议的核心问题,进而探讨水力侵蚀导致不同种类土壤微生物多样性变化的差异及其作用机制。[结果] 水力侵蚀过程导致土壤有机碳矿化作用形成碳循环中的"源"效应,而沉积过程导致有机碳迁移至低洼处固存形成碳循环中的"汇"效应,微生物的呼吸和分解作用可能解释土壤碳循环中消失的碳"汇"问题;水力侵蚀过程削弱细菌群落结构复杂性,而沉积过程可增加细菌群落结构的复杂性,但侵蚀和沉积过程都可能降低土壤真菌的α多样性和群落结构复杂性;水力侵蚀过程通过影响土壤有机碳含量、植被覆盖度和土壤pH等因素间接影响土壤微生物多样性。[结论] 未来研究应强化不同尺度水力侵蚀过程对土壤碳循环的影响机制、水力侵蚀过程与土壤微生物多样性的相互作用机制及水力侵蚀过程中土壤微生物对碳循环的影响机制相关量化研究。

Research Progress on the Effects of Hydraulic Erosion on Soil Carbon Cycle and Soil Microbial Diversity

[Objective] In response to the controversy over the "source-sink" effects of hydraulic erosion on soil carbon cycle, the impact mechanism of hydraulic erosion on soil organic carbon mineralization and soil microbial diversity were reviewed and the directions and precautions of quantitative research in this field in the future were presented. [Methods] Based on the conception and theory of "source effects" and "sink effects" of hydraulic erosion on soil carbon cycle, the core issues of the current controversy over the "source-sink" effects of hydraulic erosion on soil carbon cycle were analyzed, and then the differences of soil microbial diversity changes among different types of soil microorganisms caused by hydraulic erosion and their mechanisms were discussed. [Results] The "source effects" of hydraulic erosion on soil carbon cycle were mainly caused by the organic carbon mineralization during erosion progress, while the "sink effects" were mainly caused by the migration of soil organic carbon to the low-lying areas for sequestration during deposition process. The respiration and decomposition of soil microorganisms resulted in the disappearance of carbon "sinks" in the soil carbon cycle. Hydraulic erosion process weakened the complexity of bacterial community structure, while the deposition process increased the complexity of bacterial community structure. However, both erosion and deposition processes weakened the α-diversity and the structure complexity of fungal community. Hydraulic erosion process indirectly impacted soil microorganisms diversity mainly through altering the soil organic carbon content, vegetation cover and soil pH. [Conclusion] Further research should strengthen the quantitative research on the influence mechanism of hydraulic erosion process on soil carbon cycle at different scales, the interaction mechanism between hydraulic erosion process and soil microbial diversity, as well as the influence mechanism of soil microorganisms on soil carbon cycle during hydraulic erosion progress.