生物质炭具有农田固碳和养分固持的独特性质，已成为当今世界土壤环境领域的研究热门。迄今为止，南方双季稻种植区有关生物质炭对红壤水稻土氮素固持转化及其有效性的影响与机理，还缺乏深入系统的研究。本项目拟以水稻秸秆生物质炭为供试材料、红壤水稻土为供试土壤，通过土柱淋溶模拟试验，分析秸秆生物质炭对土壤NH4+和NO3-吸附固持的影响，明确秸秆生物质炭阻控红壤水稻土氮素损失的可行性；通过田间定位试验，研究土壤氮素供应和植株氮素吸收对秸秆生物质炭施用的响应，阐明生物质炭与氮肥互作对红壤水稻土氮素有效性的影响及其后效；采用15N自然丰度法，分析秸秆生物质炭施用对土壤氮素转化的影响；采用荧光实时定量PCR等分子手段，研究秸秆生物质炭施用条件下土壤氮相关功能微生物群落组成和丰度的变化，揭示生物质炭影响土壤氮素转化的微生物学机制，从而为作物高产、氮肥和秸秆资源的高效利用、保护农田生态环境提供科学依据。

Due to its distinct properties of carbon sequestration and nutrient retention, biochar has become a hot research topic in the field of soil environment in the world. So far, however, the effects and mechanisms of biochar amendment on N retention, transformation and its availability in red paddy soils are not sufficient and systematical enough yet. In this study, soil column is used to study the effect of rice straw-derived biochar addition on retention of ammonium (NH4+) and nitrate (NO3-) in red paddy soil. Through this research, can be clarified the feasibility of biochar amendment to reduce N loss in red paddy soils. In order to find out the effects of biochar on the availability of soil nitrogen, meanwhile, the interactions of biochar and nitrogen fertilization on plant and soil would be studied by fixed field experiment. To explore the way of nitrogen transformation, 15N natural abundance techniques would be used to identify the variation in abundances of stable nitrogen isotope in red paddy soils. Meanwhile, the effect of biochar on abundances of N-related functional microbial communities would be studied by real-time quantitative PCR, which can reveal the transformation mechanism of soil nitrogen by microorganisms. The result of our study can help provide the scientific basises for high yield, efficiently utilizing nitrogen and crop straw, and protect the eco-environment of the farmland.