Ground based nitrogen status of canola leaves using charged coupled device imaging sensor.

Rapid, non-destructive estimation of nitrogen content of crop is a potentially important application for both farm managers and researchers. This paper presents the development of a multi-spectral nitrogen deficiency sensor, which uses three channels (green, red, near-infrared) of crop images to estimate nitrogen level of the canola. The utility of a Charged Coupled Device Imaging Sensor for rapidly and nondestructively assessing foliar N status of canola was evaluated in two experiments. The sensors assess the nitrogen stress by means of the estimated SPAD value of the canola based on canola canopy reflectance sensed using three channels (green, red, near-infrared) of the multispectral camera. 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. Based on the results obtained from this study (The correlation was 0.89.), it can be concluded that a multi-spectral CCD camera can provide sufficient information to perform reasonable SPAD values estimation on-the-go during field operations.