Evaluation of Cotton Yield, Quality, and Plant Growth Response to Soil-Applied Potassium II. Multi-Year Sites

The potassium rate by placement trial was conducted at six locations around the U.S. Cotton Belt in states ranging from Virginia to Arizona. The objectives of the three year study was to evaluate the response of upland cotton (Gosspyium hirusutum) to varying rates of potassium and different placement strategies over a three year period. Potassium rates and placement strategies were implemented on the same plots across years and nutrient status of cotton, lint yield, and lint quality was measured as well as changes in soil potassium levels were measured each spring prior to cotton planting. The potassium rates evaluated were 0, 40, 80, 120, and 160 lb K₂O per acre. These rates were applied as broadcast granular 0-0-60 or injected in a band 6 inches from the row as fluid 0-0-15 formulation. Responses across locations varied due to differences in climate and soil types. The study did provide insight into potassium use across the cotton belt when a common variety was used and how potassium is utilized over time with various application rats and placement strategies.