The paper is based on the chosen results of two one-year field experiments which were conducted in the vicinity of Bydgoszcz (Poland) and in the vicinity of Cukurova (Turkey). The aim of the study is to present the comparison of yields of chosen watermelon cultivars grown in the different climatic-soil conditions under drip irrigation with N fertigation. The experiment in Turkey was carried out under better soil conditions than in Poland - watermelon plants were cultivated on the clay loam and fine sand, respectively. ‘Crimson Sweet' and ‘Sugar Baby' cultivars were tested in the experiment in Poland, and two other cultivars (‘Madera-F1', ‘Paladin-F1') were examined in the experiment in Turkey. Nitrogen of 120 kg N was applied in two different nitrogen forms (G - granule nitrogen; L - liquid nitrogen). In the second treatment (L), the liquid N fertilizer was given with irrigation water (fertigation). All plots were drip irrigated. Higher irrigation water rate was supplied in Turkey (251.7 mm) than that in Poland (157.5 mm). Average yields of watermelon ranged from 32.62 to 37.87 t.ha-1, and from 29.09 to
30.35 t.ha-1, in the experiment in Poland and in the experiment in Turkey, respec-tively. Yields were dependent on cultivar and treatment (experimental variant). The yields of ‘Crimson Sweet' and ‘Madera-F1' cultivars in treatment with combined N application (granule and liquid N) were higher than these of treatment with granule N source. Fruit weight ranged in both the trials from 3.0 to 5.5 kg. ‘Sugar Baby' and ‘Madera-F1' cultivars were characterized by the highest fruit weight (5.5 kg and 5.2 kg, respectively) under combined N application. From results, it can be concluded that watermelon yield could be increased by application of liquid N fertilizer. Amongst the four cultivars, ‘Crimson Sweet' and ‘Madera-F1' gave higher yields under conditions of applications of granule together with liquid nitrogen form.
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