Efficacy of organomineral fertilizer and un-amended compost on the growth and yield of watermelon (Citrullus lanatus Thumb) in Ilorin Southern Guinea Savanna zone of Nigeria

Background Over the years, the use of organic materialsin farming has reduced due to the increase in the use ofchemical fertilizers which are rich in readily available plantnutrients. Intensive use of inorganic fertilizers may havedepressing effect on yield of watermelon. Field experimentwas conducted at the Teaching and Research Farm, KwaraState University Malete, Kwara State, Nigeria, to study theeffects of different rates of Organomineral fertilizer GradeA, un-amended compost Grade B and NPK mineral fertilizeron the growth and yield of Citrullus lanatus.Results There were significant differences (P.05)among the treatments in relation to vine length, number ofleaves, average weight of fruits and yield. NPK at 200 kg/ha had the highest vine length of 294.67 cm followed byorganomineral fertilizer Grade A applied at 2.5 t/ha whichhad the value of 268.0 cm. Un-amended compost Grade Bat 1.5, 2.0 and 2.5 t/ha had vine length values of 257.7,259.0 and 259.7, respectively. All the fertilizer treatmentssignificantly (P.05) had higher number of leaves thancontrol. The highest fruit yield of watermelon (36.7 t/ha)was obtained from organomineral fertilizer Grade A at2.5 t/ha and NPK.Conclusion From this study, the use of organomineralfertilizer in the cultivation of watermelon could be used asalternative to mineral fertilizer, although cost effective butdifficult to procure and cannot substantially redress thephysical fragility of the soil. It is recommended that organomineralfertilizer Grade A at 2.5 t/ha be adopted forwatermelon cultivation in the study area.