Qin Qian, Zhu Shi-Shuo, Xia Bin, Zhao Yun-Ge, Xu Ming-Xiang
College of Forestry, Northwest A & F University, Yangling 712100, China.
State Key Laboratory of Soil Erosion and Dry-land Farming on the Loess Plateau, Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resource, Yangling 712100, China.
Huan Jing Ke Xue. 2019 Apr 8;40(4):1973-1980. doi: 10.13227/j.hjkx.201810035.
Soil erosion affects the soil environment and exerts an important impact on the soil organic carbon distribution, deposition, conversion, and carbon dioxide emission. The soil microbial biomass carbon can respond sensitively to these changes. The soil microbial biomass carbon under erosion and sedimentation conditions was studied for the erosional slopes at five organic carbon levels at typical erosion and deposition sites in the hilly loess plateau region. Through the study of the soil microbial biomass carbon in the rainy season, the influencing factors and their degree of influence on the soil microbial biomass carbon of the slope soil under erosion-sedimentation conditions were analyzed. The results showed that ① Soil erosion lead to significant spatial and temporal differentiation in the soil temperature and humidity and the soil organic carbon in the erosion and sedimentary area on the slope, and the degree of differentiation was related to the soil organic carbon level. ② The soil microbial biomass carbon increased significantly at the end of the rainy season, with an increase of 91.08%-286.83%. The soil microbial biomass carbon content in the slope sedimentary area was higher than that of the erosion area. With increasing soil organic carbon level, the difference between the soil microbial biomass carbon content of the erosion and sedimentary area increased, and its spatial differentiation increased. ③ The soil microbial biomass carbon in the erosion and deposition areas responded differently to the soil organic carbon content, temperature, soil moisture, and other factors. Before the rainy season, the soil microbial biomass carbon was most sensitive to soil moisture changes. However, at the end of the rainy season, the soil microbial biomass carbon was most sensitive to soil temperature changes in the deposition zone. The soil microbial biomass carbon was most sensitive to the soil organic carbon in the erosion zone. Soil erosion and seasonal variation were important reasons for the spatial and temporal distribution of the soil microbial biomass carbon on the eroding slopes. The differences in the sensitivity of the soil microbial biomass carbon to the different influencing factors was mainly due to the restrictive conversion of the different factors.
土壤侵蚀影响土壤环境，并对土壤有机碳的分布、沉积、转化及二氧化碳排放产生重要影响。土壤微生物生物量碳能够对这些变化做出敏感响应。针对黄土高原丘陵区典型侵蚀和沉积部位五个有机碳水平的侵蚀坡面，研究了侵蚀和沉积条件下的土壤微生物生物量碳。通过对雨季土壤微生物生物量碳的研究，分析了侵蚀-沉积条件下坡面土壤微生物生物量碳的影响因素及其影响程度。结果表明：①土壤侵蚀导致坡面侵蚀和沉积区域的土壤温度、湿度及土壤有机碳出现显著的时空分异，分异程度与土壤有机碳水平有关。②雨季末期土壤微生物生物量碳显著增加，增幅为91.08%-286.83%。坡面沉积区域的土壤微生物生物量碳含量高于侵蚀区域。随着土壤有机碳水平的增加，侵蚀和沉积区域土壤微生物生物量碳含量的差异增大，其空间分异增强。③侵蚀和沉积区域的土壤微生物生物量碳对土壤有机碳含量、温度、土壤湿度等因素的响应存在差异。雨季前，土壤微生物生物量碳对土壤湿度变化最为敏感。然而，在雨季末期，沉积区土壤微生物生物量碳对土壤温度变化最为敏感。侵蚀区土壤微生物生物量碳对土壤有机碳最为敏感。土壤侵蚀和季节变化是侵蚀坡面土壤微生物生物量碳时空分布的重要原因。土壤微生物生物量碳对不同影响因素敏感性的差异主要是由于不同因素的限制转化作用。
