Managing Phosphorus for Grain Sorghum Production.

Yield response of grain sorghum to phosphorus (P) application depends on a number of factors including residual soil P level, availability of soil moisture, soil chemical and physical properties, and variety planted.  These factors also influence the accuracy of P recommendations for grain sorghum production based on soil test results.  Commonly used as a rotational crop with cotton, growers need relevant, timely information on grain sorghum response to P recommendations across multiple growing environments and seasons.  Studies spanning four seasons were initiated in the Blacklands and Coastal Bend regions of Texas to evaluate the response of grain sorghum to P fertility management.  Supplemental P was applied where suggested to achieve soil test recommendations based on residual soil P to a 15-cm depth.  Yields at most locations were limited by a relatively dry mid season in year one and two.  Management of P applications for production of grain sorghum based on current soil test recommendations appears to be optimal across seasons and locations.