Abstract: In order to investigate the effects of two tillage patterns i.e. no tillage (Z) and deep plowing (C) on winter wheat canopy spectral reflectance and its first order derivative spectra under enhanced 20% UVB radiation, a field experiment was conducted, by simulating enhanced UVB radiation and using FieldSpec Pro FR. The experiment was designed to two levels of UVB radiation i.e. control (N, ambient) and enhanced (U, 20%) and thus four treatments: ZU，ZN，CN，CU. The results showed that canopy spectral reflectance could monitor well the combined effects of enhanced UVB radiation and different tillage patterns. For four treatments, their differences mainly in near infrared spectra and filling stage was the best period to monitor wheat growing. In filling stage, enhanced UVB radiation led to the significant decrease of canopy spectral reflectance in nearinfrared spectra, meanwhile the reflectance under Z treatment were much lower than that under C treatment.Since no tillage could delayed leaf senescence,the nearinfrared reflectance under Z treatment usually suffered smaller influence from enhanced UVB radiation than that under C treatment.For the firstorder derivative spectra of winter wheat canopy, the four treatments appeared obvious discrepancy in flowering and filling stages. Enhanced UVB radiation caused the significant decline in the red peak height. Red peak height under Z treatment was much lower, the red spectrum position was closer to the red spectrum and had multiple peaks compared with C treatment. The results could provide theoretical reference for applying canopy reflectance spectroscopy into the monitor of winter wheat growing under different tillage patterns.

Key words: Winter wheat, UVB, Tillage methods, Canopy reflectance spectroscopy, First order derivative spectra