ABSTRACT Potato is one of the most economically important crops in Brazil. In this crop, potassium (K) is the most accumulated nutrient and has significant and positive effect on potato plant growth and tuber yield. Thus, the aim of this work was to determine the effects of K doses on nutrients accumulation, biometric, chlorophyll, and K indexes in potato plants grown. Two experiments were installed simultaneously in an unheated greenhouse with Agata cultivar. The experiment 1 was carried out in pot with commercial organic substrate with five K doses (0, 0.66, 1.32, 1.98, and 2.64 g dm3−1). The experiment 2, nominated hydroponic system, with washed sand above a layer of expanded clay pebbles where the plants received daily nutrient solution application. The treatments were five K doses (0.0, 2.5, 5.0, 7.5 e 10.0 mmol L−1). The biometrics data were collected 21 days after emergence and at harvest. Both experiments were set at a randomized block design with four replications. In both experiments, no visual symptoms of deficiency or excess were observed but only in plants at 0 mmol L−1 of K. In both experiments, K doses interacted with some biometric and chlorophyll indexes measured in the fourth completely expanded leaf with portable SPAD and Dualex devices, commonly used as a guide to in-season fertilizer N management, leading to recommend their use only in plants properly nourished in K. K critical concentration in the fourth fully expanded leaf was 61.7 g kg−1.

中文翻译：

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在有机和水培条件下，作为钾剂量函数的小块茎马铃薯中的营养素积累、生物特征、叶绿素和钾指数和产量

摘要马铃薯是巴西最重要的经济作物之一。在该作物中，钾 (K) 是积累最多的养分，对马铃薯植株生长和块茎产量具有显着而积极的影响。因此，这项工作的目的是确定 K 剂量对马铃薯植株中养分积累、生物特征、叶绿素和 K 指数的影响。两个实验同时安装在带有 Agata 栽培品种的未加热温室中。实验 1 在具有商业有机底物的锅中进行，具有五种 K 剂量（0、0.66、1.32、1.98 和 2.64 g dm3-1）。实验 2 指定了水培系统，在膨胀的粘土鹅卵石层上方使用洗过的沙子，植物每天在此处接受营养液施用。治疗是五个 K 剂量（0.0、2.5、5.0、7.5 e 10.0 mmol L-1）。生物识别数据是在出苗后 21 天和收获时收集的。两个实验均采用随机区组设计，重复四次。在这两个实验中，没有观察到缺乏或过量的视觉症状，但仅在 0 mmol L-1 K 的植物中观察到。在这两个实验中，K 剂量与在第四个完全展开的叶子中测量的一些生物特征和叶绿素指数相互作用，带有便携式 SPAD 和Dualex 设备通常用作季节性肥料氮管理的指南，因此建议仅将其用于以 K 适当滋养的植物。第四个完全展开的叶子中的 K 临界浓度为 61.7 g kg-1。