基于包络线消除法的油菜氮素营养高光谱评价  

Hyperspectral evaluation of rape nitrogen nutrition using continuum-removed method

作　　者：张雪红[1] 刘绍民[2] 何蓓蓓[3] 

机构地区：[1]南京信息工程大学遥感学院,南京210044 [2]北京师范大学地理学与遥感科学学院,遥感科学国家重点实验室,环境遥感与数字城市北京市重点实验室,北京100875 [3]南京信息工程大学学生工作处,南京210044

出　　处：《农业工程学报》2008年第10期151-155,共5页Transactions of the Chinese Society of Agricultural Engineering

基　　金：国家自然科学基金项目(40701130);南京信息工程大学科研基金(S8107297001);国家高技术研究发展计划课题(2007AA12Z175)资助

摘　　要：该文将广泛应用于岩矿高光谱分析中的包络线消除法借用至鲜叶片的光谱分析及作物氮素营养状况评价。利用油菜主要生育期的不同氮处理下鲜叶片反射光谱及全氮含量数据,对鲜叶片可见光波段反射光谱进行包络线消除处理,以及吸收特征与叶片全氮含量的统计分析。结果表明:在可见光区域,叶片反射率随着施氮量的增加而减小,包络线消除处理扩大了原始反射光谱中由氮素胁迫引起的吸收特征微小变化。在油菜的苗期、现蕾期至开花始期三个生育期中,550～750 nm波段的红光吸收峰总面积、吸收峰左面积和吸收峰右面积均随着施氮量的增加而增大,面积归一化最大吸收深度均随着施氮量的增加而减小。相关分析表明,苗期叶片全氮含量与吸收特征参量相关性最为密切。进一步基于各光谱吸收特征参数建立了油菜氮素营养的评价模型,这些评价模型除现蕾期外,其他均达到了1%的极显著性水平。研究表明,利用包络线消除法为定性和定量评价油菜氮素营养是可行的,苗期是利用光谱吸收特征来定量评价油菜氮素营养的最佳生育期。The hyperspectral reflectance for fresh rape leaves and total nitrogen content were acquired at primary growth stages under different nitrogen levels. A new method was developed for estimating the nitrogen nutrition of rape using continuum-removed method, which generally used in spectra analysis of rock and mineral. Based on the continuum-removed treatment and the correlation between absorption feature parameters and total nitrogen content of fresh leaves, results show that reflectance at visible region decrease with the increase of the nitrogen fertilization, and continuum-removed operation can magnify the subtle difference in spectral absorption characteristics arisen from the nitrogen stress on rape. During the seeding stage, bud-emerging stage and flowering stage of rape, total area of absorption peak, left area of the absorption peak and fight area of the absorption peak in 550-750 nm region increased with the increase of the nitrogen fertilization, but it was opposite for the normalized maximal absorption depth. The correlation analysis indicated that it is at the seeding stage that the relation ship between absorption characteristics parameters and leaf total nitrogen is the most closely significant. In addition, the regression models were made between all absorption characteristics parameters and total rape nitrogen, and the models were all at 1% significance level except the bud-emerging stage. The research demonstrates that continuum-removed method is a feasible method for quantificational evaluation of rape nitrogen nutrition, and seeding stage of rape is the best stage for assessment of rape nitrogen nutrition based on absorption characteristics of fresh leaves.

关 键 词：油菜 包络线消除 氮素营养 高光谱 

分 类 号：S123[农业科学—农业基础科学]