紫云英油菜间作系统抑制土壤碳排放的微生物机制

High carbon emission is an important factor impacting agriculture sustainable development, while appropriate intercropping planting system can reduce the emission. The latest research shows that intercropping Chinese milk vetch with rape can not only improve farmland productive benefits but also inhibit soil carbon emission in farmland, but the inhibiting mechanism is unknown yet. This project designs 3 treatments including Chinese milk vetch monoculture, rape monoculture and intercropping Chinese milk vetch with rape in field experiments. It aims to research respiration characteristics and microbial change rules in farmland and rhizosphere soil further, and combine soil hydrothermal factor with soil carbon and nitrogen and other environmental factors to analyze 1) the inter link between soil carbon emission and different soil microbial group; 2) response relationship between different microbial group and soil environment, clarifying the roles of soil microbial in soil carbon emission and soil environment and revealing microbial mechanism how intercropping Chinese milk vetch with rape inhibit soil carbon emission. This research contributes to clarify mechanism of soil carbon emission in field, and provide theoretical foundation and decision-making basis for improving the quality and efficiency of agriculture, energy conservation and emission reduction in China.

高碳排放是影响农业可持续发展的重要因素，而适宜的间作种植系统具有一定的减排潜力。最新研究表明，紫云英间作油菜不仅可以提高农田生产效益，还可抑制农田土壤碳排放，但其抑制机制尚不明确。本项目将通过大田试验，设置紫云英单作、油菜单作和紫云英油菜间作3个处理，进一步研究农田和根际土壤呼吸特征及其微生物变化规律，并结合土壤水热因子、土壤碳氮等环境因子，一是分析土壤碳排放与不同土壤微生物类群的内在联系，二是分析不同微生物类群与土壤环境之间的响应关系，进一步明确土壤微生物在土壤碳排放与土壤环境之间扮演的角色，揭示紫云英油菜间作系统抑制土壤碳排放的微生物机制。本研究有助于进一步阐释农田土壤碳排放的机理，为我国农业提质增效和节能减排提供理论依据和决策基础。

高碳排放是影响农业可持续发展的重要因素。适宜的间作种植系统具有一定的减排潜力，但其减排机制尚不明确。本项目明确了紫云英油菜间作体系的土壤呼吸特征，阐明了土壤微生物与土壤水热、碳氮、根系分泌物等的关系，试图揭示紫云英油菜间作系统抑制土壤碳排放的微生物机制。研究结果发现：①在苗期和蕾薹期，间作的土壤CO2通量比紫云英单作和油菜单作的均值高1.4倍；相反，在花期和角果期，紫云英单作的土壤CO2通量比间作高1.6倍；土壤湿度的变化是调节土壤呼吸的重要因素。②紫云英油菜间作不仅可以提高土壤氮含量，还可以改变土壤微生物群落多样性；紫云英油菜间作对土壤水分和氮素的影响是促成土壤微生物群落变化的关键因素。③紫云英油菜间作改变了作物的根系分泌物特征，其变化特征与苯系物、脂类和类脂分子关系密切。可见，紫云英油菜间作通过调节土壤湿度，有减少农田CO2排放的潜力。因此，未来可以考虑紫云英油菜间作，有助于农田减排、调节土壤碳氮和改善微生物多样性。本研究进一步阐释了农田土壤碳排放的机理，可为我国农田减排提供理论依据和决策基础。