Soil Potassium Effects on Cotton Yield, Quality, and Growth in the Texas High Plains

When comparing typical soil potassium (K⁺) levels observed in west Texas to current soil K⁺ critical levels for cotton, deficiencies are rarely present and thus applications of K⁺ are rarely recommended. However, when K⁺ is applied to soil there is a positive response in yield of cotton. The focus of this experiment is to determine the correct amount of K⁺ that is needed for the improvement of cotton yield, quality, and growth. The main objectives of this research are: 1) Determine the amount of plant available K⁺ ; 2) Evaluate application methods and rates on K⁺ that effect cotton yield, quality, and growth; 3) Evaluate the effect of irrigation on K⁺ uptake ; and, 4) Reevaluate soil K⁺ concentrations in order to improve soil recommendations to maximize yield. Treatments consisted of two application methods, broadcast (0-0-60) and knife injected (0-0-15) using rates of 0, 40, 80, 120, and 160 lb K/acre applied two weeks before planting. Two irrigation levels of low (4.7”) and high (9.8”) were applied throughout the season. Soil samples were taken pre-season at depths of 0-6”, 6-12”, and 12-24”, leaf tissue samples were taken 2 weeks after first bloom. The impact of the K⁺ rates and sources on lint yield and HVI fiber quality parameters will also be determined.