In Season Application of Nitrogen and Sulfur in Wheat.

Sulfur (S) requirement for Oklahoma winter wheat is generally met through annual precipitation. Critical factors such as S soil test level, soil type, amount of nitrogen fertilizer being applied and the amount of S obtained via atmospheric deposition and plant tissue S are necessary to monitor before applying S fertilizer. Experiments were conducted at Lake Carl Blackwell, Perkins and Lahoma research stations in the fall of 2014, with the objective of assessing the effect of N and S fertilizers applied both pre plant and foliar on grain yields and protein of winter wheat in Oklahoma. The experimental design was a randomized complete block with three replications at all sites. Three preplant S rates, 0, 3, and 6 kg S ha⁻¹ and two preplant N rates, 0 and 40 kg N ha⁻¹ were applied as CaSO4 and urea ammonium nitrate (UAN, 28%N). Three rates, 0, 3 and 6 kg S ha⁻¹ MAX-IN SULFUR (13% S) and also included 0 and 20 kg N ha^-1UAN were foliar applied at the flag leaf growth stage. Preplant soil samples were taken at two depths 15cm and 45 cm. Soil samples were collected at Feekes growth stage 5 (F5) and at harvest. Leaf samples were collected at F5 and flag leaf stages.  Head counts were also taken at harvest. Test weight, grain yield will be reported, including total grain N and S. Results show that in season application of N and S can increase wheat grain yield and protein.