Evaluation of Starter Fertilizers for Grain Sorghum Production in Oklahoma.

The sorghum producers of Oklahoma are requesting regionally specific recommendations for the use of both traditional starter fertilizers, such as ammonium poly phosphate (10-34-0, APP) and those products at which are being pushed upon them by industry.  At this time the university extension professionals are reliant upon research preformed in the surrounding states which may or may not be suitable to the specific conditions of Oklahoma grain sorghum production.   In addition there is little peer reviewed published research on the addition of S and no published work on potassium, iron, zinc, or orthophosphates. The goal of the project is to identify and demonstrate nutrient management practices which will 1) Increase sorghum yield while minimizing nutrient inputs; 2) Provide a regionally specific body of data upon which sorghum specific starter fertilizer recommendations can be developed.  Field experiments were conducted across a diverse range of environments in Oklahoma on both research farms and farmer fields, to address the objectives stated above. Specific sites were selected to represent significant sorghum production areas with a range of potential yield regions, irrigation schemes, and soil type environments.  The hybrid was maintained while populations weed control practices, tillage systems and rotations used will be those appropriate for each location. The study was conducted over eight site years and consisted of 14 treatments replicated three times in a RCBD.  Plots consisted of four rows (.762 m spacing) 6.1 m in length.  The center two rows of each plot were harvested at maturity.