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

Cotton yield potential has increased, which should increase the potassium (K) demand. Potassium fertilizer applications are rarely recommended due to soil K levels in west Texas being reported as greater than the critical level of soil K (125-150 ppm). When K fertilizer is applied pre-plant to the soil research has shown a positive response on cotton yield. In this experiment lint yield and reproductive development were evaluated at Lamesa and New Deal, TX in 2016 and 2017. The main objectives were to: 1) evaluate application methods and rates of K fertilizer that may affect cotton yield, quality, and growth, 2) determine the interactive effect of K fertilization on plant reproductive development at distinct sets of nodes; and, 3) re-evaluate soil K concentrations in order to improve soil recommendations to maximize yield in the Texas High Plains. Treatments consisted of two K application methods, broadcast (0-0-60) and knife injected (0-0-15) at five rates (0, 45, 90, 135, and 180 kg K ha^-1). Two irrigation levels that applied seasonal totals of 11.4cm (low) and 17cm (high) were also included. Box mapping was conducted on 1m per row length of the plot. Box mapping is used to determine the effect of K on specific groups or zones of reproductive positions. Results indicated that high irrigation increased lint yield, leaf tissue K, and boll counts. Lint yield was increased by broadcast K application in Lamesa, TX in 2016.