Crop Canopy Sensor Utilization for Nitrogen Management in Corn Under Semi-Arid Limited Irrigation Conditions.

The primary goal of precision agriculture is to increase the efficiency of on-farm inputs such as nitrogen (N) by determining in-field variability that affects crop growth.  Several methods of determining the variability within a field have proven successful for increasing the efficiency of N management.  One such method is the use of ground-based active crop canopy sensors. Research studies have shown that crop canopy sensor produced reflectance data can provide valuable information about in-season variability in corn.  These sensors also allow for the determination of crop variability at specific times and locations throughout the growing season without the limitations of traditional remote sensing platforms (i.e. weather or flight concerns). Crop canopy sensors are being used to determine the temporal and spatial nitrogen (N) requirements of irrigated corn, thereby increasing the efficiency of N and limiting potential environmental degradation.  However, crop canopy sensor N application algorithms have not been adequately developed or adapted for use in semi-arid climates where an array of water management techniques ranging from fully irrigated to dryland are practiced.  Therefore, a study has been initiated to determine the viability for sensor use for N management in a semi-arid climate under an array of irrigation regimes.  Previous study results suggest that the sensors will be a viable option under these conditions, but modifications of sensor algorithms used in wetter climates will be required.