Directed Rx: A New Method for Variable Rate Nitrogen Prescription in Cotton

Directed R_X is a method developed by Clemson researchers in an effort to optimize zone delineation and assignment of inputs for spatially variable prescriptions. Currently employed methods of variable rate prescription development generally overlay rates or products (e.g. hybrids) on pre-defined yield management zones, with a number of studies focused on how to best define these management zones. In cotton, algorithms for variable rate nitrogen prescriptions have been developed on the basis of normalized difference vegetation index (NDVI), which is used to calculate in season estimated yield (INSEY). The Directed R_X method uses strip tests to integrate yield and therefore profitability effects with site-specific foundation (e.g. soil EC, elevation, irrigation) polygons, seeking to optimize prescriptions, specific to a field and input.