【摘要】 通过田间试验,测定了不同施氮水平下冬小麦冠层在6个典型生育期地上部分全氮和硝态氮含量以及冠层光谱,系统分析了单波段反射率、可见光和近红外波段组合而成的归一化植被指数(NDVI)、比值植被指数(RVI)等8种常见植被指数与相应时期地上部分全氮和硝态氮含量的相关性。结果表明,施氮量增加,全氮、硝态氮含量、冠层近红外波段反射率都随之增加,但当施氮量增加到300 kg/hm2(一次性施入)时,上述各项指标均降低;整个生长期中孕穗期在近红外区域反射率最高,与可见光波段反射率相差最大;6个生育期单波段510~1 100 nm反射率、NDVI、RVI等8种植被指数与全氮和硝态氮含量呈显著或极显著相关,植被指数的相关性较单波段高,且与全氮的相关性明显大于与硝态氮的相关性。选择NDVI(560 nm,760 nm)和NDVI(660 nm,760 nm)可以准确拟合冬小麦地上部分全氮和硝态氮含量,对前者的拟合度>0.80,对后者的拟合度>0.53。更多还原

【Abstract】 In a field experiment that was conducted at six typical growth stages of winter wheat,we measured total N and NO3--N of above ground and canopy spectral reflectance in different N status,then analyzed the correlation between the single wavebands,NDVI/RVI and other vegetation indices that visible light and near infrared combined and total N,NO3--N concentration.The results showed that total N,NO3--N of above ground and canopy spectral reflectance in near infrared increased with the increasing of nitrogen rate until 300 kg/hm2(applied one-off);There was remarkable correlation between single wavebands from 560 nm to 1 100 nm,and the correlation coefficient of vegetation index was higher than single wavebands reflectance and increased from reviving to filling stage gradually,and the former was obviously better than the latter;The ability of NDVI/RVI of 560 nm and 660 nm in visible light and 760 nm,1 100 nm and 1 200 nm in near infrared combined were better than other wavelengths.NDVI(560 nm,760 nm) could estimate the content of above ground total N and NO3--N accuracy.These results indicated that canopy spectral reflectance could be used to non-destructively monitor N status in winter wheat.更多还原