Hyperspectral Data and Their Relationships Correlative to the Pigment Contents for Rice Under Different Nitrogen Support Level

The hyperspectral reflectances of the canopy, the leaf on the main stem of two varieties of rice are measured by a ASD FieldSpec Pro FR FM in field and indoor under 3 nitrogen support levels in different stages. The contents of chlorophyll and carotenoid of canopies and leaves corresponding to the spectra were determined. The spectral difference are clear for the canopy and leaves of rice under different nitrogen levels, and the spectral reflectance are gradually getting smaller in the visible region and bigger in the near infrared region along with nitrogen level increasing. The spectral reflectance of the third unfolding leaf from the top on the main stem were bigger than that of the first one from the top in the visible region and the near infrared region at jointing stage and booting stage. There were `red shift' phenomena before booting and `blue shift' after heading for the position of red edge λ red, slope of red edge Dλ red and area of red edge S red of the canopy spectra. The leaf area indices(LAI), above ground fresh biomass(AFM), above ground dry biomass(ADM) and fresh leaf mass(FLM) were very significantly correlative to the spectral variables R 1200/R 550, R 990/R 550, R 800/R 550, R 750/R 550, λ red and S red. The pigment contents of canopies and leaves were also significantly correlative to the spectral variables R 800/R 550 and λ red. This indicated that some right spectral variables would be used to estimate the LAI, AFM, ADM, FLM and the pigment contents of canopy and leaf for rice.