Abstract：
The decomposition and utilization of plant-derived carbon by microorganisms and carbon fixation are crucial pathways for enhancing soil organic carbon (SOC) storage. However, a gap remains in our understanding of the impact of microorganisms on the decomposition of plant-derived carbon and their capacity for carbon fixation in crop rotation systems. Based on a 12-year experiment with wheat-maize (WM), wheat-cotton (WC), and wheat-soybean (WS) rotations, the microbial communities and carbon cycle function were investigated. The results indicated that WS rotation significantly increased SOC content compared to WM and WC. In addition, a significant increase was observed in microbially available carbon and microbial biomass carbon in the WS soil compared with those in the others. Further analysis of the microbial community factors that influenced SOC content revealed that WS rotation, in contrast to WM rotation, enhanced the diversity and richness of bacteria and fungi. Analysis of microbial carbon decomposition functions revealed an increase in starch, lignin, and hemicellulose decomposition genes in the WS soil compared to the others. The changes in carbon decomposition genes were primarily attributed to six bacterial genera, namely Nocardioides, Agromyces, Microvirga, Skermanella, Anaeromyxobacter, and Arthrobacter, as well as four fungal genera, namely Dendryphion, Staphylotrichum, Apiotrichum, and Abortiporus, which were significantly influenced by the crop rotation systems. In addition, microbial carbon fixation-related genes such as ACAT, IDH1, GAPDH, rpiA, and rbcS were significantly enriched in WS. Species annotation of differential carbon fixation genes identified 18 genera that play a role in soil carbon fixation variation within the crop rotation systems. This study highlights the impact of crop rotation systems on SOC content and alterations in specific microbial communities on carbon cycle function.
摘要：
微生物对植物来源的碳的分解和利用以及碳固定是增强土壤有机碳（SOC）存储的关键途径。然而,我们对微生物对植物衍生碳分解的影响及其在作物轮作系统中固定碳的能力的理解仍然存在差距。基于小麦-玉米(WM)的12年试验，小麦-棉花（WC），和小麦-大豆(WS)轮作，研究了微生物群落和碳循环功能。结果表明，与WM和WC相比，WS旋转显着增加了SOC含量。此外,与其他土壤相比，WS土壤中的微生物有效碳和微生物生物量碳显着增加。对影响SOC含量的微生物群落因素的进一步分析显示，WS轮换，与WM旋转相反，增强了细菌和真菌的多样性和丰富度。对微生物碳分解功能的分析显示淀粉的增加，木质素,与其他土壤相比，WS土壤中的半纤维素分解基因。碳分解基因的变化主要归因于六个细菌属，也就是诺卡迪亚,Agromyces,Microvirga,斯克曼内拉,厌氧细菌,和节杆菌,以及四个真菌属，也就是树突状,葡萄球菌,吡虫啉,和流产,受到作物轮作系统的显著影响。此外,微生物碳固定相关基因，如ACAT，IDH1,GAPDH,rpia,和rbcS在WS中显著富集。差异碳固定基因的物种注释确定了18个属，它们在作物轮作系统中的土壤碳固定变化中起作用。这项研究强调了作物轮作系统对SOC含量的影响以及特定微生物群落对碳循环功能的变化。
