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 <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.

中文翻译：

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棉花产量对美国棉花带土壤施钾的响应

在整个美国棉花带，棉花 ( Gossypium hirsutum L.) 的钾 (K) 缺乏症状在过去十年中变得更加普遍。2015-2017 年，在阿拉巴马州、阿肯色州、路易斯安那州、密西西比州、北卡罗来纳州、俄克拉荷马州、南卡罗来纳州、德克萨斯州的两个地区和弗吉尼亚州进行了总共 23 个站点年的实验。目标是 (a) 量化代表性土壤中的深度土壤 K 水平，在这些土壤中，棉花通常生长在观察到缺钾的主要棉花产区；(b) 评估施用方法和钾肥率对棉皮产量、贷款价值和化肥投资回报的影响。在种植前 2-4 周，分别以 0、45、90、135 和 180 kg K ₂撒播或注入颗粒状和液体氯化钾哦哈^-1。德克萨斯州和俄克拉荷马州以外的地方通常土壤钾含量<150 mg kg ^-1，Mehlich III 临界钾含量，因此，预期对施用钾肥的产量响应。然而，在 23 个站点年中，在 5 个站点年确定了治疗效果。其中两个，德克萨斯州威廉姆森县和弗吉尼亚州遭受了严重的水分胁迫，导致产量低（<526 kg 皮棉 ha ^-1）。2015 年在德克萨斯州拉伯克县的位置确定了对刀注入 0-0-15 的积极皮棉产量响应 - 一个高产量的位置（>1,653 kg 皮棉公顷^-1）。位置之间不一致的产量响应表明土壤 - 棉花植物系统中的 K 动态尚不清楚，值得继续研究。