Development of Nitrogen Parameter Detector for Orchard Monitoring Based on Spectroscopy

摘要

In order to monitor nitrogen content of the jujube tree in the orchard, a spectroscopy-based nitrogen parameter detector was developed. It was designed with one control unit and several measuring sensor nodes. The sensor nodes were used to measure the canopy reflectance of jujube tree plant. Each sensor node contained four optical channels to measure the sunlight and canopy radiation at the wavebands of 550, 650, 766 and 850nm respectively. The control unit was applied to receive, display and store all the data sent from several sensor nodes. The data was transferred based on ZigBee wireless network. The transmission quality between the sensors and control unit was evaluated. The result showed that the signals could be transmitted precisely without packet loss when the distance was less than 100m. The calibration experiment indicated that the minimum correlation coefficient between illuminometer and each light channel of the sensors was 0.917. The NDVI (650, 766) was calculated from the developed sensor and used to monitor the nitrogen content of jujube tree in the orchard with r(2)=0.638. It provides a new method to monitor the nitrogen parameter in the orchard non-destructively.