Impact of Soil Applied Potassium on Cotton Yield, Quality, and Plant Growth in Texas

In recent years, potassium (K) deficiencies in cotton (Gossypium hirsutum L.) have occurred somewhat unpredictably across the US Cotton Belt. In Texas, this includes the Blacklands and Coastal Plains production regions. Cotton plants can display K deficiency symptoms even when the soil tests levels are considered sufficient. When insufficient K is available, cotton yield and fiber quality is reduced, as well as an increasing susceptibility to foliar diseases. A multiple year study (2012-2015) was conducted to evaluate the rate and application method of K on cotton yield, quality, and growth. Soil samples were collected to determine K levels at the surface and to a depth of 4 feet. Treatments of 0, 40, 80, 120, and 160 lb/a of K was obtained through granular KCl (0-0-60) broadcast and incorporated and liquid KCl (0-0-15) injected fertilizer. The K was applied 2-3 weeks before cotton planting.  The cotton variety planted was DP 1321B2RF, an early-mid maturity.  In-season data collection included: plant height, nodes to first fruiting branch, total nodes, nodes above cracked boll, and leaf tissue sampling. The plots were harvested and ginned using a 10-saw tabletop gin. Lint samples were sent to Cotton Inc. to test fiber properties by HVI analysis. The data are being analyzed using statistical methods to determine the treatment effects on K use efficiency, yield, fiber quality, and return on investment.