稻麦叶片氮含量与冠层反射光谱的定量关系  

Quantitative relationship between leaf nitrogen concentration and canopy reflectance spectra in rice and wheat

作　　者：朱艳[1] 李映雪[1] 周冬琴[1] 田永超[1] 姚霞[1] 曹卫星[1] 

机构地区：[1]南京农业大学/江苏省信息农业高技术研究重点实验室

出　　处：《生态学报》2006年第10期3463-3469,共7页Acta Ecologica Sinica

基　　金：国家自然科学基金资助项目(30400278;30571092);江苏省自然科学基金资助项目(BK2003079;BK2005212);高校博士点基金资助项目(20030307017)~~

摘　　要：作物氮素含量是评价作物长势、估测产量与品质的重要参考指标,叶片氮素含量的无损快速监测对于指导作物氮素营养的精确管理及生产力的预测预报具有重要意义.以5个小麦品种和3个水稻品种在不同施氮水平下的3a田间试验为基础,综合研究了稻麦叶片氮含量与冠层反射光谱的定量关系.结果显示：（1）不同试验中拔节后稻麦叶片氮含量均随施氮水平呈上升趋势;（2）稻麦冠层光谱反射率在不同施氮水平下存在明显差异,在可见光区（460～710 nm）的反射率一般随施氮水平的增加逐渐降低,而在近红外波段（760～1100 nm）却随施氮水平的增加逐渐升高;（3）就单波段光谱而言,610、660 nm和680 nm处的冠层反射率均与稻麦叶片氮含量具有较好的相关性;（4）在光谱指数中,归一化差值植被指数NDVI（1220,610）与水稻和小麦叶片氮含量均具有较好的相关性,且相关性好于单波段反射率;（5）对于小麦和水稻,可以利用共同的波段和光谱指数来监测其叶片氮含量,采用统一的回归方程来描述其叶片氮含量随单波段反射率和冠层反射光谱参数的变化模式,但若采用单独的回归系数则可以提高稻麦叶片氮含量估测的准确性.Nitrogen concentration in crop plants is a key index for assessing plant growth status and predicting grain yield and quality. Non-destructive monitoring and diagnosis of plant nitrogen status is of significant importance for precise nitrogen management and productivity forecasting for field crops. The present study was conducted to determine the quantitative relationships of leaf nitrogen concentration to canopy reflectance spectra in both wheat and rice. Ground-based canopy spectral reflectance and nitrogen concentrations in leaves were measured with six field experiments consisting of five different rice varieties and three different wheat varieties and varied nitrogen fertilization levels aeruss six growing seasons. All possible ratio vegetation indices （RVI）, difference vegetation indices （DVI）, and normalized difference vegetation indices （NDVI） of sixteen wavebands from the MSR16 radiometer were calculated. Analyses were made to determine the relationships of seasonal canopy spectral reflectance and all possible vegetation indices to leaf nitrogen concentrations in rice and wheat under different nitrogen treatments and variety types. The results showed, as expected, that nitrogen concentrations in wheat and rice leaves increased with increasing nitrogen fertilization rates. Canopy reflectance, however, was a more complicated relationship. In the near infrared portion of the spectrum （760 - 1100 nm）, canopy reflectance increased with increasing nitrogen supply, whereas in the visible region （460 - 710 nm）, canopy reflectance decreased with increasing nitrogen supply. For both rice and wheat, leaf nitrogen concentration was best evaluated at 610, 660 and 680 nm. Among all possible RVIs, DVIs, and NDVIs, the NDVI（ 1220, 610） was most highly correlated with leaf nitrogen concentrations in both rice and wheat. In addition, the correlation of NDVI（1220,610） to leaf nitrogen concentration was found to be higher than that of individual wavebands at 610, 660 and 680nm in both rice and

关 键 词：小麦 水稻 叶片氮含量 冠层反射率 光谱指数 定量关系 

分 类 号：S511[农业科学—作物学] S512.1