Study on nitrogen stress characterization of rape based on ground multi-spectral imaging sensor

This paper presents the development of a multi-spectral nitrogen deficiency sensor, which uses three channels (green, red, near-infrared) of crop images to determine nitrogen level of the rape. The core of this investigation is the calibration methods between the multi-spectral references and the nitrogen levels in crops measured using a SPAD 502 chlorophyll meter which may be used to measure N (g)/leaf area (m2). Some noticeable relationships between the multi-spectral reflectance and SPAD readings were found from this study.