Potassium Fertilization for Higher Flowering and Fruit Yield in ‘Magallanes’ Pummelo (Citrus maxima)

This study aimed to determine the influence of Potassium (K) fertilization on the flowering and fruit yield of 13-year old ‘Magallanes' pummelo [Citrus maxima (Burm. ex Rumph.) Merr.] trees. The experiment was conducted at South Davao Corporation (SODACO) farm, Davao City, Philippines for 12-month duration. Five treatments with increasing K levels were applied per tree: control, no K, 150 g K basal, 225 g K basal, and 225 g K basal + foliar application. Flowering, fruit set and yield of pummelo were enhanced by higher K rates. Flowering was increased by 4 times while fruit set by 86-100%. Fruit number was increased by 7 times, weight per fruit by 22-26%, and yields up to 9 times with 100% (return of investment) ROI on trees applied with 225 g K rates. The results of the study indicated the important role of K in improving the flowering, fruit yield and income of ‘Magallanes' pummelo.