北方旱地农田植物源碳向土壤碳酸盐转化的微生物机制

在全球多地的旱地农田中，发现了植物源碳向土壤碳酸盐转化的现象。农田土壤无机碳的增加对提升土壤碳汇潜力，维持土壤健康，提高作物生产力具有重要意义。针对该现象，除了已发现的物理化学过程的转化机制之外，近年来的研究表明，微生物过程的转化机制亦不容忽视，但目前对该机制的研究尚不清楚。项目拟以中国华北平原麦玉轮作的旱地农田为研究对象，运用宏转录组学、稳定碳同位素示踪、室内控制培养、扫描电镜分析和X射线衍射分析等手段，主要研究：（1）微生物转化植物源碳为碳酸盐的代谢途径及类群识别；（2）微生物转化植物源CO2为土壤碳酸盐的过程；（3）微生物转化植物源草酸钙为碳酸盐矿物的过程。项目旨在揭示微生物将两种形式的植物源碳转化为土壤碳酸盐的过程，明确微生物转化机制。预期结果为深入了解旱地农田土壤固碳途径和潜力提供新的视角和理论基础；同时也可为科学评价和调控旱地农田生态系统服务功能提供科学依据。

The carbon transformation process from plant to carbonate has been found in dry farmlands in the worldwide. The increase of soil inorganic carbon in these farmlands is of great significance for enhancing the potential of soil carbon sink, maintaining soil health, and promoting crop productivity. As for the mechanisms of this process, apart from the discovered physical and chemical mechanisms, recent studies have shown that the mechanisms of microbial transformation should not be ignored, on which few studies have examined. To address this, we focus on the wheat-maize rotation farmland in north China as the study object, and comprehensively employ the approaches of metatranscriptomics, stable carbon isotopic tracing, manipulation experiments, scanning electron microscope analysis, and X-ray diffraction analysis to conduct investigations as follow: (1) the microbially metabolic pathways and taxa of carbon transformation from plant to carbonate, (2) the microbial process of plant-derived CO2 transforming into soil carbonate, and (3) the microbial process of plant-derived calcium oxalate transforming into carbonate minerals. The project aims to reveal the processes by which soil microbes convert both forms of plant-derived carbon into soil carbonate, and to clarify the mechanisms of microbial transformation. The expected results would provide a new perspective and theoretical basis for further understanding the pathway and potential of soil carbon sequestration in dry farmland; and would can provide scientific basis for scientific evaluation and regulation the ecosystem services of dry farmland.