中文摘要：

研究红边面积参数与叶层氮素状况的定量关系，有助于水稻（Oryzasativa）生长信息的实时无损获取及精确追氮管理。该研究基于多年不同施氮水平和不同水稻品种的冠层高光谱数据，系统分析了水稻的红边区域光谱、面积形状特征及其与叶层氮浓度的定量关系。结果表明，水稻冠层红边区域微分光谱随不同氮素水平变化出现“三峰”现象，峰值分别出现在700、720和730nm附近，且3个波段的峰值高低发生交替变化；同时，以3个峰值波段为中心与X坐标轴组成的微分光谱面积和形状相应发生变化。发现基于两两峰值波段划分所得红边子面积所构成的比值（双峰对称度）、归一化差值（归一化对称度）参数与叶层氮浓度具有密切的定量关系，可作为估测水稻叶层氮浓度的红边面积形状参数。经曲线拟合和模型检验的结果显示，双峰对称度DPS（A675-700,A675-755），即由675～700nm区域面积与675—755nm区域面积的比值，和DPS（A7301755,A675-700）（由730-755nm区域面积和675～700mm区域面积的比值）对水稻叶层氮浓度的估测效果最好，可用于不同水稻品种和生长条件下的叶层氮浓度估测。

英文摘要：

Aims Quantifying the relationship between red edge area parameter and canopy leaf trogen status is the foundation for real-time and non-destructive monitoring of crop growth status and precision nitrogen fertilization in rice （Oryza sativa）. Our objectives were to analyze 1） characteristics of the first-derivative reflectance spectra in red edge area and 2） the quantitative relationship of red edge area shape parameters to canopy leaf nitrogen concentrations, using different nitrogen levels and rice varieties and based on canopy hyper-speetral reflectance of field-grown rice in different years. Methods Spectrum in the red edge area was significantly affected by different nitrogen levels and different rice varieties, and a ＂three-peak＂ feature could be observed with the first derivative spectrum at about 700, 720 and 730 nm. The maximum heights of the three peak bands changed with different nitrogen levels, so sub-areas surrounded by the first derivative spectra curve and x coordinate were formed by dividing the red edge area with the ＂three-peak band line＂. Two random sub-areas were selected to calculate ratio （double peak symmetry, DPS） and normalization （normalized double peak symmetry, NDPS）, which were related to canopy leaf nitrogen concentrations. Important findings DPS based on the ratio of two different red edge sub-areas, and NDPS with normalization of the two different red edge sub-areas were significantly related to leaf canopy nitrogen concentrations in rice. Results of model calibration and validation indicated that DPS （A675.700, A675-755） and NDPS （A675-700, A675-755）, ratio and normalized difference of areas in 675-700 to 675-755 nm red edge region, respectively, performed the best in estimating leaf canopy nitrogen concentration. Thus, these two spectral indices were suitable red edge area shape parameters for monitoring leaf canopy ni- trogen concentrations in rice.