Fertilizer rates for increased pineapple production in the tropical ferrallitic soils of South Western Nigeria

The investigation studied the optimal fertilizer rates and mixtures for maximum production of smooth cayenne pineapples in the tropical ferrallitic soil.Fertilized pineapples were significantly (P = 0.05) superior in growth and fruit yield to the unfertilized control. Nitrogen and potassium were the most critical nutrients. Nitrogen deficiency manifested within 6 months of planting as reduced, thorny and pink coloured leaves resulting in over 10 months delayed plant crop harvest and over 38% reduction in fruit yield. Less than 20% of pineapples which lacked nitrogen remained productive during the first ratoon crop. However, when nitrogen was increased twofold (100 to 200 kg/ha/year), the fruit of the plant crop doubled with 15-10% increased fruit lodging. Potassium significantly (P = 0.05) reduced fruit lodging and improved fruit yield and flavour.Nitrogen further enhanced the effective utilization of P and K for significant yield increases. Thus, the interaction between high nitrogen (200 kg/ha/year) and low phosphorus (50 kg/ha) or high potassium (200 kg/ha) respectively, significantly (P = 0.05) increased the yield of pineapples, while P and K interaction retarded growth, delayed crop maturity and reduced the fruit yield and quality. Pineapples which received fertilizer mixture of NPK 200-50-200 produced the highest and best quality fruits and was therefore recommended for optimum yield of pineapples in the tropical ferrallitic soils.