Assessment of the influence of soil nitrogen supplies and variable fertilization on winter wheat growth condition using airborne hyperspectral image

Pushbroom Hyperspectral Imager(PHI)is a hyperspectral imaging sensor with 80 wavebands from 411.9 nm to 832.8 nm which was developed by Shanghai Institute of Technical Physics of Chinese Academy of Sciences. From April to May in 2002, three airborne images were acquired at different winter wheat growth stages in Beijing precision agriculture demonstration base. The flight height was 1000 m and the spatial resolution of image reaches 1 m when the hyperspectral images were rectified and spectrally calibrated. In this paper, some spectrum characteristic parameters which are sensitive to winter wheat growth condition were obtained from images, combined with data of soil basic nitrogen content, soil total nitrogen supplies, nitrogen of variable fertilization, analysis between spectrum characteristic parameters and soil data show that soil basic nitrogen is a pivotal factor to wheat growth. And its influence lasts during the whole winter wheat growth stage. Furthermore, analysis based on the change of wheat spectrum information between two growth stages of winter wheat shows that variable fertilization can improve the growth of wheat. It can also eliminate some growth differences caused by spatial difference of soil basic nitrogen.