Spatial ET Field Mapping Using Sensors Mounted on a Center Pivot.

Site-specific irrigation management is becoming more important a means for improving crop water use efficiency and reducing water wastage, especially as competition for quality water resources increases. Continuous geo-referenced canopy temperature measurements using sensors mounted on a center pivot irrigation system can provide near real-time temporal and spatial estimates of crop water use at the field scale. These estimates are useful in providing decision support for site-specific variable rate irrigation systems. This presentation discusses the relationship between crop water use derived from neutron meter readings and a soil water balance equation with an integrated crop water stress index (CWSI) calculated over daylight hours for management zones across a center pivot field.