Lewis, KatieMorgan, GaylonFrame, William HunterFromme, DanielDodds, Darrin M.Edmisten, Keith L.Robertson, BillBoman, RandyCutts, TreyDelaney, Dennis P.Burke, Joseph AlanNichols, Robert L.2021-07-202021-07-202021-05-110002-19621-15http://hdl.handle.net/10919/104231Across 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 <less than 150 mg kg(-1), the Mehlich III critical K level, and thus, a yield response to applied K fertilizer was expected. However, among the 23 site-years, a treatment effect was determined at 5 site-years. Two of those, Williamson County, Texas, and Virginia endured severe moisture stress and resulted in low yields (<526 kg lint ha(-1)). A positive lint yield response to knife-injected 0-0-15 was determined in 2015 at the Lubbock County, Texas, location-a location with high yield (>1,653 kg lint ha(-1)). Inconsistent yield responses among locations indicate that K dynamics in the soil-cotton plant system are not well understood and deserve continued investigation.application/pdfenCreative Commons Attribution-NonCommercial-NoDerivs 4.0 InternationalArticle - Refereedhttps://doi.org/10.1002/agj2.207191435-0645