Utilizing N-P-K-S Rich Strips in Oklahoma Winter Wheat Production.

Nutrient needs are variable from field to field and fluctuate from year to year. This study was conducted to improve nutrient use efficiencies, demonstrate ability to visually identify nutrient needs throughout a cropping season, along with the evaluation of current genetic varieties and soil nutrient recommendations across divergent environments. This project is an extension of the N-rich strip concept which is used to identify in season nitrogen deficiencies. Nutrient rich strips of nitrogen, phosphorous, potassium, and sulfur were applied at forty three sites across Oklahoma, on multiple soil types with a wide range of environmental conditions and wheat varieties. Urea (46-0-0), triple super phosphorous (0-46-0₎, potash (0-0-62) and gypsum (0-0-0-17) were used as the source of nitrogen, phosphorous, potassium and sulfur respectively. Product was applied at a rate of 224 kg ha^-1 to a one by thirty meter strip in farmer fields. At two of the sites, perpendicular strips were applied to measure the interaction between nutrients. Nutrient strips and farmer practice strips were sensed with GreenSeeker™ sensor (NDVI) for an estimate of biomass.  At maturity three one m² subplots were hand harvest from each strip. Samples were threshed, grain weight recorded for yield and grain samples analyzed for nitrogen, phosphorous, potassium and sulfur content.