Research on fluorescence spectral characteristics of rice under various conditions of nutrient application at several growth stages showed- nitrogen deficiency cause the peak intensities in the bule-green waveband decrease at effective tillering stage and increase from invalid tillering stage

it also cause the peak intensities in the red waveband and the ratios between peak intensities （such as 440 nm/550 nm） decrease during the whole growth stages. It is possible to monitor the conditions of nutrientsupply through charact ristic changes in fluorescence spectra of rice leaves

the optimum monitoring waveband is between 400 nm and 800 nm and the optimum monitoring period is between flourishing tillering stage and booting stage.