中文摘要：

【目的】利用实时冠层反射光谱监测水稻（Oryza sativa）植株氮素营养状况并推荐氮肥追用量,以实现高产、优质、高效水稻生产。【方法】基于不同基施氮量处理,利用水稻拔节期的差值植被指数（differential vegetation index,DVI）实时估测植株氮积累量,进而根据构建的追氮调控模型精确估算穗肥用量,最后研究基于反射光谱的水稻追氮调控效应。【结果】不同基施氮量处理下的水稻植株在穗肥施用期的氮素积累状况差异较大,基于追肥调控模型,高施基氮量处理的追氮量较对照调低（高氮低调）,中施基氮量处理的追氮量较对照微高（中氮微调）,而低施基氮量处理的追氮量较对照显著调高（低氮高调）。追施氮肥后,各调控处理间的植株氮含量（PNC）和差值植被指数（DVI）逐渐趋于一致。而调控处理的叶片净光合速率（Pn）和氮肥农学利用率较各自对照明显提高,并获得了更高的经济效益。与常规高产施氮处理相比,低氮高调、高氮低调处理Pn、干物质积累量、氮积累量、产量以及氮肥农学利用率等均有所提高。【结论】与传统非定量经验施肥相比,基于反射光谱的水稻追氮调控技术根据植株氮积累量和土壤供氮量而精确量化氮肥追用量,是一种较好的追肥精确管理技术。

英文摘要：

【Objective】The objective of the study is to estimate nitrogen（N） status of rice plant and recommend top-dressing N amount based on canopy reflectance spectra,so as to achieve higher yield,better grain quality and higher economic efficiency. 【Method】The amounts of nitrogen fertilizer recommended for top-dressing of different treatments with varied basal N rates were calculated with the newly developed N top-dressing model based on plant N accumulation,which was estimated from differential vegetation index（DVI） .Then the N top-dressing regulation effect was studied.【Result】The results showed that plants of different treatments with varied basal N rates had different N accumulations at the elongation stage.The treatments with high,medium and low basal N rates needed low,relative higher and high N fertilizer supplies,respectively.After N top-dressing,the differences of plant N concentration（PNC） and DVI between the regulation treatments and their CKs were induced gradually.And leaf photosynthetic rates（Pn） of the regulation treatments were significantly increased compared with their CKs.And higher economic benefits were also achieved in regulation treatments than its CKs.Compared with the normal high yield N treatment,the regulation treatments obtained higher Pn,dry matter accumulation,plant N accumulation,grain yield and nitrogen agronomic efficiency. 【Conclusion】Compared with the normal methods,the real-time top-dressing regulation technique based on reflectance spectra can quantify varied N top-dressing amounts induced by different plant and soil N status,so it is recommended for N top-dressing in rice.