不同碳源对土壤异养硝化作用的影响及其微生物机制

异养硝化过程是土壤氮素转化的一个重要环节，但是迄今为止，对异养硝化作用影响因素及发生机制的认识仍不清楚。已有研究表明，土壤有机碳是影响异养硝化作用的重要因素。然而，分解能力不同的碳源对异养硝化作用及其氧化亚氮（N2O）产生具有怎样的影响？影响机制是什么？尚未得到一致的结论。针对这一科学问题，本项目以中国中温带、暖温带、亚热带林地和农田土壤为研究对象，以15N和13C稳定同位素标记实验方法为手段，测定不同碳源对土壤异养硝化作用及其N2O产生速率的影响；采用定量PCR、Miseq高通量测序技术和微生物纯培养、回接土壤等技术，探究不同碳源对异养硝化作用的影响机制。研究结果对于阐明土壤异养硝化作用的发生规律和作用机制，完善土壤氮素循环的知识体系具有重要意义。

Heterotrophic nitrification is an important process of soil nitrogen transformation. However, its controlling factors and the microbial mechanism is still unclear. The previous studies revealed soil organic carbon (SOC) played an important role on soil heterotrophic nitrification. However,there is still not consensus about the effect of SOC with different decomposition properties on soil heterotrophic nitrification and its N2O emission. And the research on the mechanism behind the effect of SOC is still lacking. In this project, forest and cropland soil samples from the middle temperate, warm temperate and subtropical zone in China will be collected. The effect of different carbon sources on soil heterotrophic nitrification and its N2O production will be studied using the 15N and 13C-15N tracer experiments. The Real-Time PCR and Miseq high throughput sequencing technologies will be performed to investigate the responsible microorganisms for soil heterotrophic nitrification. And the technology of microbial pure culture and inoculation will be conducted to testify the effect of different carbon sources on the responsible microorganisms. The project is aiming to reveal the regularity and mechanism of soil heterotrophic nitrification, which will provide a scientific basis for completing the knowledge of soil nitrogen cycle.