The Influence of Nitrogen and Phosphorus on Watermelon Fruit Quality

This study was done to elucidate the effects of nitrogen (N) and phosphorus (P) on fruit quality of watermelon. The experimental design was a split-plot laid down in randomized complete blocks with three replications. The treatments were 0, 50, 100, 150 and 200 kg N/ha (main-plots) and 0, 25, 50 and 75 kg P/ha (sub-plots). There were no interactions between N and P treatments on all the dependent variables analyzed. Application of 50, 100, 150 and 200 kg N/ha to watermelon plants significantly (P < .0001) increased fruit quality (lycopene content, vitamin C, titratable acidity and fruit rind thickness) compared to fruit from control plants. However, P application had no significant (P = .05) effects on fruit lycopene content, vitamin C content, titratable acidity, soluble solids content and fruit rind thickness compared to fruit from control plants. In conclusion to optimize watermelon fruit quality, application of 150 kg N/ha and 50 kg P/ha to watermelon plants was recommended.