The experiment was carried out on a farm, in the Borborema County, State of São Paulo, from February to April 2002, in Typic Paleudult. The objective of this work was to investigate the influence of sources and doses of potassium on fruit yield characteristics of seedless watermelon. The experimental design was randomized complete blocks, with three replications, in 3 x 4 factorial scheme, corresponding respectively to potassium sources (potassium chloride, nitrate, and sulphate) and doses (50, 100, 200, and 300 kg K2O ha-1). The highest number of fruits per plant (1,7) was achieved with 172 and 182 kg ha-1 K2O, using respectively KNO3 and KCl as fertilizers. Fruit weight was influenced only for potassium doses and 158 kg ha-1 K2O promoted the largest weight. Maximum yield were obtained with 94.1, 183.0, and 193.4 kg ha-1 K2O, using respectively K2SO4, KCl, and KNO3. Each kg of K2O used as K2SO4 yielded 201,6 kg of fruits, whereas the same amount of K2O as KCl and KNO3 yielded respectively 111,5 and 109,6 kg of fruits.
Citrullus lanatus; plant nutrition; potassium fertilizers
