Effects of Vegetation Types on the Potential and Pathway of Microbial Carbon Sequestration in Reclaimed Soil of Open-pit Mine
- YOU Yun-nan, ZHU Yan-feng, CHEN Fu, CHENG Yan-jun, DONG Wen-xue, MA Jing
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Since the semi-arid open-pit mining activities have seriously damaged the local ecological environment, it is urgent to clarify the interaction mechanisms among vegetation, soil and microorganism. Meanwhile, it is of great significance for large-scale ecological restoration of damaged mines to explore the potential and pathway of microbial carbon sequestration, and stimulate the self-recovery ability of degraded ecosystems, as well as achieve the nature-based solutions. For this purpose, 18 topsoil samples of three typical replanting types, namely Pinus tabulaeformis (YS), Pinus tabulaeformis + poplar (DYS), and Pinus tabulaeformis + poplar + alfalfa (DYX), were collected from the waste dump of Heidaigou open pit mine in Zhungeer Banner, Inner Mongolia. High-throughput sequencing and real-time fluorescence quantitative PCR were used to determine the abundance of soil microbial carbon fixation genes and the community structural variation. The results indicate that:(1) The vegetation types presented a significant impact on the physiochemical characteristics of the reclaimed soil (P<0.05). The more complex vegetation types, the more significant the decrease in soil pH and water content, as well as the more significant increases in organic carbon, total nitrogen, and nitrate nitrogen. (2) The vegetation types had no significant effect on the bacterial community structure in the reclaimed soil, but showed a significant effect on the abundance of carbon sequestration genes, i. e. the abundances of rbcL, korA, acsA, acsE, pccA, smt, and frda were significantly increased with the increasing of varieties in the vegetation types (P<0.05). (3) Soil water content, organic carbon, total nitrogen, and nitrate nitrogen are the dominant factors for bacterial community structure changes, while different vegetation combinations altered the environmental factors to manipulate carbon sequestration potential and pathways. This study could help to understand the impact of diversified vegetation combination on the carbon cycle of reclaimed soil in mining areas, and provide the theoretical basis for ecological restoration, carbon sequestration and sink enhancement in the Loess Plateau.