RESPONSE OF 'SMOOTH CAYENNE' PINEAPPLE TO ORGANIC FERTILIZER IN SOUTH WESTERN NIGERIA

Between August 2008 and January 2010, a study was conducted at the University of Agriculture Abeokuta, Nigeria to determine the optimum rate of composted poultry manure (PM) for organic pineapple. The pineapple plantlets were spaced 60×30 cm in paired rows separated by a 1.5 m corridor, on a low fertility sandy soil. Composted poultry manure was applied at the rate of 0, 2.5, 5.0, 10.0 and 20.0 t/ha. A first trial was performed with PM applied at transplanting and, in a second trial, PM was applied 10 months after transplanting (MAT) and the application rate was increased to 40 t/ha. At 4 MAT, the effects of 10 or 20 t PM/ha applied at the early vegetative phase did not differ significantly and compared to non PM soil amendments, both rates significantly increased plant height, leaf area and canopy diameter, but not total dry matter accumulation. Between 10 and 15 MAT, poultry manure applied at the late vegetative phase did not significantly affect vegetative growth. At 2 MAT foliar contents of N and P increased with the rate of PM applied, while K peaked at 2.5 t PM/ha and declined thereafter. At 12 MAT, foliar Mg and Ca content peaked at 5.0 and 10.0 t PM/ha, respectively. Compared to no application of PM, the rate of 5 t PM/ha doubled fruit yield (41 t/ha) and further yield increases at higher PM rates were small. For optimum yield of pineapple in south western Nigeria application of poultry manure at 15 t/ha (10 t at planting followed by 5 t/ha 10 months later) is recommended.