The ratio and illumination of wheat plant’s leaf and stalk in spectrometer’s field of view change due to wheat lodging

so it is possible to detect the lodging grade by remote sensing technique.Firstly

the spectral difference between leaf and stalk is analyzed

and how canopy spectral reflectance increases with lodge angle is explained.Secondly

because the relative increase of spectral reflectance in visible bands is larger than in near infrared bands

the significant negative correlation model between lodging angle and NDVI was built by statistical analysis.Finally

two LandSat ETM satellite images of April7（before lodging）andMay9

2003（after lodging）were selected

and the ratio of NDVI derived fromthe two images was statistically correlated to the lodging grade

and the lodging grade was successfully regressed.