水位控制与施氮对水稻根际氮素转化的影响研究

Rice is amongst the most important crops, and is also the largest water and fertilizer consummer and give great contribution to the non-point source pollution in China. Improper water and fertilizer management has caused the serious resources and environment crisis. This study takes consideration in plant rhizosphere where biogeochemical processes of soil-crop-microbial system take place) and nitrification (the key process of nitrogen transformation in farmland ecosystem), through investigating on rice root morphology and function, the rhizosphere habitat, soil microorganisms and nitrogen transformation activities, etc., by means of soil-core experiment, rhizo-box test. Researching into the effects of soil environment variable on soil microorganisms, nitrifying/denitrifying enzyme activity and mechanism of nitrogen use efficiency, etc, and to establish the response models would help optimize paddy field water and nitrogen management and guiding a high grain yielding, water-saving, fertilizer-saving, environmentally friendly rice cropping pattern.

水稻是最重要的粮食作物，同时是我国用水量最大、化肥消费量最多作物，对农业非点源污染有重要贡献，其主要原因在于稻田水肥的不合理施用。本研究从根际（土壤-作物-微生物系统中生物地球化学活动发生的热点部位）和硝化作用（农田生态系统氮素转化关键过程）入手，通过土芯试验、根箱试验和测坑试验研究水稻根系形态及功能、根际环境、土壤微生物和氮素形态变化规律等，试图探讨土壤环境变量影响土壤微生物、硝化/反硝化酶活、氮素利用效率等的机理，并建立相关模型，为水稻水肥优化管理，对建立稻田高产、节水、省肥、减排的高效水稻种植模式优化得到高效高产、节水、省肥、减排的高效水稻生产模式的建立具有重要指导意义。