THE EFFECTS OF DIFFERENT IRRIGATION METHODS AND NITROGEN FORMS WITH VARIOUS AMOUNTS ON THE YIELD AND SOME QUALITY PARAMETERS OF WATERMELON

The research was carried out at Research and Production Farm of Agricultural Faculty, Cukurova University during 1996 and 1997 growing season. In this experiment, different irrigation methods (S: Sprinkler; D: Drip), nitrogen forms (L: Liquid; G: Granule) with various amounts (based on applied line source sprinkler irrigation method, N-1; N-2; N-3 kg/da) and two varieties of watermelon (P: Paladin; M: Madera) were studied. Free water surface evaporation was used to determine irrigation water amount. In only SL and SGL treatments, three different nitrogen levels were formed providing gradient situation during the irrigation season. Based on the results, irrigation water ranged from 119.2 mm (first year) to 350.5 mm (second year). Nitrogen applications varied from 5.1 kg da(-1) (SL) to 10 kg da(-1) (SG) in the all treatments. Total yield changed between 1325 kg da(-1) (first year) and 5013 kg da(-1) (second year) depending on year and treatments. Although, the highest yield was taken from treatments in which liquid fertilizers were applied for both of the varieties in the first year. The varieties have different response to form and amounts of nitrogen in the second year. In this year, the highest yield was obtained from SG treatment in Paladin variety. The yield decreased only by 12% in SL treatments that nitrogen was applied in liquid form. In Madera variety, the highest yield was taken from SGL treatments that granule and liquid fertilizer were applied together. The effects of irrigation methods and nitrogen levels on some quality parameters of watermelon were found to be insignificant (P>0.05). However, fruit diameter of Madera was larger than Paladin variety. The longest fruit length was measured in Paladin-DL treatment. As a result, it was determined that watermelon yield was increased by nitrogen which was applied through irrigation water. Therefore, it could be said that watermelon yield increased considerably with applying nitrogen together with irrigation water in each irrigation application.