中文摘要：

基于连续两年的水稻氮磷互作盆栽试验,于水稻拔节、抽穗、灌浆等主要生育时期同步测定了冠层反射光谱和水稻植株总氮含量,系统分析了350~1 330 nm波段范围内任意两波段组合而成的差值（DVI）、比值（RVI）及归一化（NDVI）光谱指数与植株总氮含量的关系,筛选了可用于氮磷互作环境下的最佳光谱指数,建立了估算模型,并与已有的水稻氮光谱反演指数进行了比较。结果表明：氮磷交互下水稻冠层光谱受氮素的影响明显高于磷素,呈现随施氮量的增加可见光区反射率下降,近红外区上升的规律;但对磷肥的响应受施氮水平的影响,施磷在缺氮情况下提高了可见光区和近红外区的反射率,不缺氮情况下却使可见光区反射率降低。与植株总氮含量相关性较好的波段组合基本不受植被指数构造形式的影响,表现较为稳定,主要分布在近红外（780~1 330 nm）/可见光（750~770 nm）区域、红边（640~700 nm）区域和可见光（450~500 nm）区域。但施磷与不施磷处理的总氮光谱指数敏感波段组合区域有所变化,施磷处理的敏感区域要小于不施磷处理,且相关性决定系数有所降低。存在对施磷不施磷处理都比较敏感的光谱指数区域,拔节、抽穗和灌浆期分别以RVI（FD719,FD740）,NDVI（FD419,FD552）,DVI（FD707,FD713）表现最佳,建模决定系数分别为0.87、0.80、0.87,几乎不受氮磷交互作用的影响,验证模型均方根误差分别为1.98、3.68、3.47。已有的氮光谱反演参数中则以m ND705、PRI、NDVI705表现最好,但其预测精度明显受磷肥作用的影响,尤其是在拔节期,不施磷处理下的精度要远低于施磷处理,且整体精度均低于本研究新选的氮光谱指数。因此,氮磷互作对水稻氮光谱反演指数的波段组合及预测精度产生影响,要提高氮素光谱诊断精度,需要根据情况选择适宜的光谱指数。

英文摘要：

A pot experiment was conducted across two successive rice growing seasons. Canopy spectral reflectance and total nitrogen（TN） of rice were measured synchronously at rice jointing, heading and filling stages. Difference vegetation indices （DVI）, ratio vegetation indices （RVI） and normalized difference vegetation indices （NDVI） with all combinations of two wavebands between 350 and 1330 nm were calculated and related to the TN, then TN estimation models were established based on the best relations. The performance of existing nitrogen spectral indices was also evaluated and compared with the new spectral indices established in this study. The influence of rice canopy spectral reflectance to nitrogen was greater than phosphorus, and showed a decrease at visible band and an increase at the near infrared region with the nitrogen rate increase. But the responses of rice canopy spectral reflectance to phosphorus were influenced by nitrogen rate. Phosphorus increased the reflectance in visible and near infrared region under the nitrogen-deficiency condition, while decreased the reflectance in the visible region under adequate nitrogen condition. The band combination of the best vegetation indices for TN estimation was similar and mainly located in the near infrared （780-1 330 nm）/ visible （750-770 nm） region, the red edge （640-700 nm） and visible （450-500 nm） region. But the TN sensitive band combination of the no phosphorus added treatment and phosphorus added treatment were different. The TN sensitive region and the determination coefficients （R2） of the phosphorus added treatment was smaller and lower than the no phosphorus added treatment. RVI（FD719, FD740）, NDVI（FD419, FD552） and DVI（FD707, FD713） were the best indicators for rice plant TN concentration at jointing, heading and filling stages, with the R2 of 0.87, 0.80, 0.87 and the RMSE for estimation of 1.98, 3.68, 3.47 respectively. The estimation models were hardly influenced by nitrogen and phosphorus interaction.