Nitrogen fertilizer effects on the melon crop yield

A study was carried at Petrolina-PE, Brazil, with the melon crop (Cucumis m elo L.), cv. Valenciano Amarelo, in a Red-Yellow Latosol with the objective of evaluating the effect of nitrogen fertilizers sources and their combina tions, applied through the conventional way and through water irrigation du ring the crop cycle. The experimental design was a split block with four re plications and nine treatments: 1. control (without N); 2. urea; 3. ammoniu m sulphate, both applied conventionally; 4. urea applied up to 42 days afte r germination; 5. ammonium sulphate applied up to 42 days after germination ; 6. urea applied up to 15 days and potassium nitrate from 16 to 42 days af ter germination; 7. urea applied up to 15 days and ammonium sulphate from 1 6 to 42 days; 8. urea applied up to 30 days and potassium nitrate from 31 t o 42 days, and 9. urea applied up to 15 days, ammonium sulphate from 16 to 30 days and potassium nitrate from 3 1 to 42 days, at the level of 80 kg/ha of N. The fertilizers used during the crop cycle(treatments 4 to 9) were a pplied through irrigation water. It was found that urea applied through fer tirrigation up to 42 days provided higher yield (31.14 ton/ha), not differi ng, however, from the other treatments, with the exception of the control a nd ammonium sulphate, which gave the lowest yields (25.06 and 24.65 ton/ha, respectively). It was found a variation in fruit mean weight from 1.63 to 1.84 kg/fruit. There was no significant difference in total soluble solid c ontent ((o)Brix) among the treatments.