Effect of Different Doses of Nitrogen and Potassium Fertilization on Yield and Nutrient Uptake in Grafted Watermelon Growing in Çukurova Region Conditions

Turkey ranks second in watermelon (Citrullus lunatus L.) cultivation in the World and Adana takes the first place in the country. Although watermelon is one of the most common crop grown in the Çukurova region, studies on optimal nitrogen (N) and potassium (K) doses in watermelon fertilization are very limited. This research was conducted to determine the optimum doses of N and K fertilization in grafted watermelon (Karain) at open field farmer conditions. For this aim, increasing doses of N (0, 6, 12, 18, 24 kg da-1) and K (0, 6, 12, 18, 24 kg da-1) were applied to soil. Main stem length (cm), main stem diameter (mm), number of nodes on main stem, total branch number, fruit yield (g bitki-1), fruit weight (g), fruit length (cm), fruit diameter (cm), fruit rind thickness (mm) and total soluble solids (%) were measured. The N% and K% concentration in shoot, fruit flesh and fruit rind were also determined. According to the results it was determined that the effect of N and K applications on the observed parameters were changed depending on the application doses. The effect of different N application doses were significant in all measured plant and fruit parameters except rind thickness. However, different doses of K applications were statistically insignificant in terms of main stem diameter, fruit yield, fruit weight, fruit length and fruit diameter. Different doses of N application did not change the concentration of K in shoot, fruit rind and fruit flesh. However the increasing doses of N application increased the N concentration in both fruit rind and fruit flesh. Application of K only affected K concentration in fruit rind while the N concentration in fruit rind and fruit flesh found to be statistically different