Estimation of Nitrogen Content in Winter Wheat Using Proximal Crop Sensors

Nitrogen (N) is an important agricultural input that affects plant growth, yield and quality. Different crop sensors have been developed to detect the nitrogen status non-destructively content crops. The present study compared the performance of the Crop-Circle and Isaria crop sensors to estimate the nitrogen content of winter wheat during the growing season. The sensitivity of sensor measurements to the water content of the crop was also investigated. Field testing was conducted during the 2012 growing season at Marquardt experimental station northwest of Potsdam, Germany. The experiment was designed as a randomized split block design with two replications. Treatments consisted of four N fertilization rates (0, 60, 120 and 240 kg N ha-1) and two water regimes (irrigated and non-irrigated). The results indicated that both Crop-Circle and Isaria crop sensors showed very high performance for detection of the nitrogen content of winter wheat. It was noted that the measurements by Crop-Circle were affected by the water content of the crop, but that Isaria showed low sensitivity to water content.