Implementation of the GreenSeeker sensor for measuring canopy leaf area index of corn

Recently, optical GreenSeeker sensor, because of its accuracy and user friendly, has attracted the attention of many farmers to use it for measuring Normalized Difference Vegetation Index (NDVI). The main objective of this study was to measure the total leaf area of plants using this optical sensor and investigate the possibility of using this sensor instead of conventional methods. The images of all plots were recorded using camera and the G-R (Green-Red) was determined as a best function to distinguish soil from the leaf. Based on the Results, an appropriate relationship between total leaf area and NDVI was obtained (R2=0.84). Results of comparing Greenseeker and chlorophyll meter SPAD-502 indicated a promising accuracy of the Greenseeker sensor (R2=0.82) in measuring the plant chlorophyll. The root mean square error resulted from the effect of organic matter on sensor output was found to be 0.048. It must be noted that every product has a specific reflection in the red and infrared bandwidth, so the model obtained in this study just can be used for corn. For the other crops it is necessary to develop specific models. Finally, it is concluded that the GreenSekeer sensor can be used to determine the total top area of canopy and it provides the possibility of comparing the total leaf area of canopy between fields.