Sources and doses of potassium affect the yield of Cucumis anguria L. in the Brazilian semiarid

The gherkin (Cucumis anguria L.) is a vegetable widely adapted to different edaphoclimatic conditions. It can be used for human consumption, being an alternative healthy nutrition source in the increasing world population. This study aimed to evaluate the yield, content of soluble solids, potassium and leaf sulfur accumulation, and the chlorophyll content of the gherkin cultivar 'Nordestino' under different sources and doses of potassium fertilizer. The experiment was carried out in a complete randomized block design, with treatments distributed in a 6 x 2 factorial scheme, with six doses (0, 50, 100, 150, 200, and 250 kg ha-¹) and two sources of K2O (potassium chloride and sulfate), in four replicates. The highest soluble solids content (3.68%) was obtained under the dose of 78.75 kg ha-¹ of K2O with potassium sulfate. The maximum dose of K2O resulted in a tissue K content of 20.7 g kg-¹, with a tissue S content of 4.49 and 3.24 g kg-¹ under the doses of 250 and 164.16 kg ha-¹ of K2O, respectively, using sulfate and potassium chloride as K source. The total yield was 7.78 t ha-1 and 6.92 t ha-1 under the doses of 102.25 and 81.75 kg ha-¹ of K2O, respectively, using sulfate and potassium chloride as sources. Based on this study, the dose of 105.45 kg ha-¹ of K2O using potassium sulfate as K source is recommended to reach the maximum productivity of the gherkin cultivar 'Nordestino'.