Impact of Fertilizer Sources and Water Supplies on the Growth and Yield of Watermelon Varieties in Oyo State, Nigeria

Background and Objective: The use of organic fertilizers is an agricultural practice that enhances soil fertility and plant quality. This study reported the influences of fertilizers on the yield of watermelons. Materials and Methods: Field experiments were conducted to assess the impacts of mineral fertilizers, organic fertilizer (Sawdust Compost, SDC) and their combinations on two varieties of watermelon during early and late raining season and under irrigation in Ogun-Osun River Basin Project Site Sepeteri, Oyo-State. Plants without mineral or organic fertilizers served as control treatments. All experiments were arranged in a Randomized Complete Block Design with three replications. Data collected, which included Crop Growth Rate (CGR), Relative Growth Rate (RGR), Net Assimilate Ratio (NAR), dry matter weight, fruit yield and plant nutrient uptake, were subjected to analysis of variance at a 5% level. Results: The results showed significant differences (p<0.05) for all the treatments tested when compared to the control. The highest value of CGR (39.86/plant) was obtained between 6-8 weeks with Kaolack variety fertilized with 13.2 t ha^–1 SDC during the late raining season. Kaolack fertilized with 13.2 t ha^–1 SDC during the early raining season produced the highest dry matter weight with the value of 88.81 g/plant. The highest mean fruit weight and fruit yield of 5.05 kg and 98.96 t ha^–1 respectively were recorded with Kaolack fertilized with 13.2 t ha^–1 SDC under irrigation. Conclusion: It is concluded that Kaolack watermelon variety fertilized at 13.2 t ha^–1 SDC fertilizer under irrigation is recommended for high fruit yields.