Sensor Based Variable Rate Application of Nitrogen by Using a Multi-Spectral Image Sensor

Abstract

This paper presents the development of a sensor-based variable-rate application system for nitrogen side-dressing in corn fields. A multispectral corn nitrogen deficiency sensor was used to provide the corn nitrogen stress information in real-time during the side-dress. This sensor assess the nitrogen stress by means of the estimated SPAD value of the corn based on corn canopy reflectance sensed using three channels (green, red, near-infrared) of the multispectral camera. Some calibration relationships between the multispectral reflectance and SPAD values have been found from previous study. A variable-rate nitrogen application model based on the estimated SPAD values was developed in this research to search for the optimal amount of nitrogen needed to achieve an optimal corn production. The nitrogen application using the sensorbased VRA system was performed at V11 stage. Based on the limited results obtained from this research, it has demonstrated that it is feasible to develop a sensor-based VRA system to achieve the goal of crop condition-based VRA to optimize the corn production “on-the-go” while performing the nitrogen application.