Furrow‐irrigated cotton yield and fiber quality response to potassium fertilization

Abstract Potassium (K) deficiency is a common yield‐limiting factor in cotton ( Gossypium hirsutum L.) production, requiring effective management to minimize yield losses and maintain fiber quality. We evaluated how K availability influences cotton lint yield and fiber quality. Ten fertilizer‐K rate (0–187 kg K ha −1 ) trials were conducted on silt loam soils with soil‐test K (STK) ranging from very low to above optimum during the 2023 and 2024 growing seasons. Cotton was planted in raised beds and furrow‐irrigated, and lint yield, turnout, and fiber quality (i.e., fiber length, micronaire, uniformity, strength, and elongation) were measured at maturity. Cotton lint yield was positively affected by fertilizer‐K rates ( p ≤ 0.10) at STK ≤ 114 mg K kg −1 . Yields were maximized at responsive sites with applications of 56 kg K ha −1 in long‐term trials and 37, 75, or 112 kg K ha −1 in single‐site‐year trials, showing yield increases of 20%, 53%, 47%, and 70% compared to the no‐K control, respectively. Lint turnout and fiber quality were affected by K availability. Overall, at yield‐maximizing fertilizer‐K rates, lint turnout was 2.4% greater across cultivars in relation to the control. Similarly, fiber elongation increased by 0.35%. At sites with Very Low STK, as little as 37 kg K ha −1 increased lint uniformity and strength up to 0.67% and 1.84 g tex −1 . Micronaire increased on average by 0.50, with greatest values occurring with 112 kg K ha −1 application. These findings suggest adequate K management is key to maximizing both cotton yield potential and fiber quality.