有机肥施用下植物根系分泌耦合土壤磷素活化的微生物机制

P mobilization driven by microbe needs C supply, and was controlled by amount and quality of rhizospheric C source. However, microbial mechanism of C-P coupling process is not well understood. In this project, 13CO2 continuous labeling combined with molecular ecological methods were conducted to study the effect of organic C input on root exudation, and DNA-SIP combined with molecular methods were performed to understand the mechanism of microbial P mobilization in peri-urban farmland of Ningbo Critical Zone Observatory(CZO). The goal of our project is to provide fundamental knowledge to: (1) understand the mechanism of root exudation response to different amount of organic fertilizer, (2) reveal the characteristic of phosphorus mobilizing bacteria under organic fertilizer input, (3) evaluate the influence of organic fertilizer on ecosystem function and (4) finally confirm the feasible management of organic fertilization for further improving efficiency of plant P uptake.

微生物磷素的活化需要碳源供给，其活化过程受根际碳源质量和输入量的调控，然而我们对碳磷耦合下的微生物机制仍缺乏了解。本项目以影响微生物参与磷素活化过程的根系分泌物入手，选取宁波樟溪流域这一城郊关键带作为研究对象，利用田间实验和微宇宙模拟实验，采用13CO2连续标记技术研究植物生长和根系分泌过程对不同有机肥施用量的响应机理；DNA-SIP结合分子生态学方法阐明不同有机肥施用水平下土壤磷素活化的微生物特征，从而评估有机肥施用对生态系统功能影响，最终确定城市化过程中其安全、适宜用量，提高植物对磷素利用效率。

微生物磷素的活化需要碳源供给，其活化过程受碳源质量和输入量的调控，然而我们对碳磷耦合下的微生物机制仍缺乏了解。本项目选取城郊关键带作为研究对象，开展了土壤微生物磷活化过程和机制的研究，主要成果包括：（1）利用田间实验和微宇宙模拟实验，结合分子生态学方法阐明了不同有机肥施用水平下土壤磷素活化的微生物特征，从而评估了有机肥施用对生态系统功能影响；（2）解析了解磷菌和生物肥的耦合利用对土壤磷素周转和植物生长的影响因素，明确提高土壤磷素活化的微生物策略；（3）基于高通量芯片技术测定相关功能基因丰度，对土壤的健康和有机肥施加量做出综合性评估，为后续提高土壤功能、改善土壤健康提供了技术支持。