Towards Variable Rate Irrigation in Kentucky

Abstract: Kentucky farm soils are known for their spatial variability that is typical for the Karst landscapes and caused by soil erosion processes leaving the land surface with a heterogeneous mosaic of infiltration capacity. Most irrigation systems in Kentucky and in the Southeastern U.S. are pivot systems that allow a spatially uniform rate of water supply. This technical limitation leads to either optimum water application, over- or under-application of water. The latter two imply not only economic losses for the farmer but also environmental harm through sub-optimal use of resources or even loss of resources through surface runoff or leaching. Little is known yet how to design an irrigation map and how to manage irrigation on the go while considering local soil properties, crop growth stage, past management, weather forecast, and technical precision of VRI system. In this project, the technicalities of variable-rate irrigation will be explored and used to compose a manual with guidance for growers on the various steps of a sound variable rate irrigation management.