| Response of the spectral reflectance to total N and NO3--N of winter wheat |
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| DOI：10.7606/j.issn.1000-7601.2010.01.20 |
| Key Words: winter wheat total N NO3--N characteristic curve of canopy spectral single wavelength vegetation index |
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| 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. |
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