The effect of leaf area index on the spectral feature of winter wheat infected with stripe rust and its elimination

摘要

Canopy spectral reflectance of winter wheat with stripe rust that was inoculated artificially at different LAI (Leaf Area Index) level was obtained. In this paper, the LAI was treated nine levels, and the spectral reflectance at nine levels was analyzed. It indicates that the spectral reflectance, which is up at red light region and is down at near infrared light region, is different significantly with LAI’s change. Meanwhile, the first derivation of canopy spectral reflectance was analyzed, and the result shows that the difference is lowest around 680nm band. The correlation between the DI (Disease Incidence) and the first derivations of reflectance was analyzed, and the result shows excitedly that the correlation coefficient is highest above 0.98 around 680 nm band. Lastly, the study shows that the LAI’s change has effect on the spectral feature of winter wheat with stripe rust, but the bands of around 680 nm were immune from the LAI’s change, then the first derivation of spectral reflectance around 680nm band can be selected to model with DI.