Cotton yield response to soil applied potassium across the U. S. Cotton Belt

Across the U.S. Cotton Belt, potassium (K) deficiency symptoms in cotton (Gossypium hirsutum L.) have become more common over the past decade. In 2015–2017, an experiment was conducted in Alabama, Arkansas, Louisiana, Mississippi, North Carolina, Oklahoma, South Carolina, two regions in Texas, and Virginia for a total of 23 site‐years. The objectives were (a) to quantify soil K levels at‐depth in representative soils where cotton is commonly grown in major cotton production regions with observed K deficiencies; and (b) to evaluate the effects of application method and K rates on cotton lint yield, loan value, and return on fertilizer investment. Granular and liquid potassium chloride were broadcast or injected, respectively, 2–4 wk prior to planting at 0, 45, 90, 135, and 180 kg K2O ha−1. Locations other than Texas and Oklahoma generally had soil K levels