Effects of Nitrogen and Potassium Rates and Timing on Cotton Yield and Fiber Quality: First Year Results

Delivering the appropriate rates of nutrients at the proper time can significantly impact yield and quality. Insufficient rates of either nitrogen or potassium could induce plant stress, while over-application may lead to luxury consumption, delayed maturity, or economic unfeasibility. Poor application timing may render nutrients unavailable when needed, while spoon-feeding applications may be logistically inconvenient or economically draining. Weather patterns, economic restraints, and an individual grower’s system are among the variables that must be considered with fertilizer applications. This research is designed to help predict and understand the effect each nitrogen and potassium rate and timing has on yield and fiber quality. Potassium treatments include one, one and a half, and two times the recommended rate applied at all at planting, split between at planting and layby, and split between at planting, layby, and 3 weeks following layby while nitrogen treatments include a total combination of 20, 80, or 110 pounds/acre at the same timing. Measurements included nodes above white flower at first bloom, second layby, and two weeks following second layby, a petiole sample two weeks following second layby, end of season plant mapping, defoliation rating, yield quality, and fiber quality. There was also a soil sample taken for K after harvest.