The applicability of VRI for managing variability in infiltration capacity and plant-available water: A preliminary discussion and GIS study

Although variable rate irrigation (VRI) has been researched and marketed for a number of years, research that quantifies the magnitude of VRI's potential benefits and that are translatable to unmonitored fields is lacking. The potential reduction in seasonal irrigation is proposed as the criterion for beginning to evaluate the use of VRI to improve agricultural water management when infiltration capacity and plant-available water are spatially variable inside a field. An initial geographic information system study using publicly available geospatial data was conducted to examine soil and topographic properties associated with such variability within 1100 center pivots across 11 counties. The current results only indicate that the extent of variability may be different between counties, but with the acquisition of more accurate and site-specific data as well as the development of a model that enables multi-year comparisons of seasonal irrigation between VRI and uniform irrigation for an individual field, the public could be finally informed about the applicability of VRI by regional assessments of VRI potential and field-specific VRI investment decision tools.