Application of red edge variables to nutrition diagnosis and grain quality forecast of winter wheat

Reflectance of vegetation canopy has a significant increase at the edges of red and near infrared spectra, the point of maximum slope occurs on the boundary between red and near infrared bands that is known as the "red edge", which was located approximately in 660～770 nm. Correlation analysis was also made between red edge variables and leaf total nitrogen and leaf soluble sugar content. Red edge position was proved to be able to predict leaf soluble sugar content, normalized minimum was chosen for the inversion of leaf total nitrogen content. Regression equations were established between the ratio of leaf total nitrogen and leaf soluble sugar content and grain protein, grain wet gluten and grain dry gluten content at anthesis stage. For this purpose red edge variables can play a vital role in providing time-specific and time-critical information for crop management and grain quality forecast.