State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, PR China; College of Forestry, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
State Key Laboratory of Soil Erosion and Dryland Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling, Shaanxi 712100, PR China; University of Chinese Academy of Sciences, Beijing 100049, PR China.
Sci Total Environ. 2021 Apr 20;766:144209. doi: 10.1016/j.scitotenv.2020.144209. Epub 2020 Dec 25.
Sustainable management practices can enhance the capacity and potential for soil carbon (C) sequestration, significantly contributing towards mitigating regional climate change. Here, we investigated how the microbial characteristics of a Pinus tabulaeformis plantation responded to different management practices to identify the role of microbial characteristics in influencing the stability of soil organic carbon (SOC). We chose a Pinus tabulaeformis plantation on the Loess Plateau where forest management practices had been conducted since 1999. Five forest management practices were implemented: two at the forest level (P. tabulaeformis with and without ground litter), and three using different vegetation restoration approaches after clear-cutting (P. tabulaeformis seedlings, abandoned grassland, and natural shrub regeneration). Microbial biomass, soil respiration, microbial community structure, microbial metabolic function, and soil oxidizable organic carbon (OC) fractions were evaluated. Forest management practices changed SOC stability by adjusting the microbial characteristics (e.g. soil microbial community diversity and microbial metabolic function diversity). The result of path analysis was that the direct path coefficient of microbial biomass on soil oxidizable OC fractions was the largest, which was 1.499. Path analysis and redundancy analysis showed that microbial biomass had the largest direct influence on soil oxidizable OC fractions. Compared with other forest management practices, natural shrub regeneration increased the nonlabile carbon fraction by increasing soil microbial characteristics, and contributed the most towards stabilizing SOC, which enhanced the stability of the soil ecosystem on the plateau. In conclusion, microbial biomass was the biggest influence factor of SOC stability. In contrast, the stability of SOC may be most stable in the area of natural shrub regeneration.
可持续的管理实践可以提高土壤碳（C）固存的能力和潜力，为缓解区域气候变化做出重大贡献。在这里，我们研究了油松人工林的微生物特征对不同管理实践的响应，以确定微生物特征在影响土壤有机碳（SOC）稳定性方面的作用。我们选择了黄土高原上的一个油松人工林，自 1999 年以来一直在进行森林管理实践。实施了五项森林管理实践：两项在林分水平上（有和没有地被物的油松），以及三项在皆伐后采用不同植被恢复方法（油松幼苗、废弃草地和天然灌丛再生）。评估了微生物生物量、土壤呼吸、微生物群落结构、微生物代谢功能和土壤可氧化有机碳（OC）分数。森林管理实践通过调整微生物特征（例如土壤微生物群落多样性和微生物代谢功能多样性）来改变 SOC 的稳定性。路径分析的结果表明，微生物生物量对土壤可氧化 OC 分数的直接路径系数最大，为 1.499。路径分析和冗余分析表明，微生物生物量对土壤可氧化 OC 分数的直接影响最大。与其他森林管理实践相比，天然灌丛再生通过增加土壤微生物特征增加了非惰性碳分数，对稳定 SOC 贡献最大，从而增强了高原土壤生态系统的稳定性。总之，微生物生物量是 SOC 稳定性的最大影响因素。相比之下，SOC 的稳定性在天然灌丛再生区可能最稳定。
