GROWTH AND YIELD RESPONSE OF YELLOW PASSION FRUIT TO ORGANIC AND INORGANIC FERTILIZERS IN SOUTH WESTERN NIGERIA

Between 2004 and 2005 at Abeokuta in south western Nigeria, four-month old seedlings of yellow passion fruit spaced 3 m × 4 m on a sandy loam soil received organic composted city refuse that was fertilizer-amended and sorted (N 0.86%, P 0.83%, K 1.05%, Ca 1.0%, Mg 0.31%, Fe 0.79%, Zn 306 mg•kg^-1) at rates of 5 t, 10 t and 20 t•ha^-1 per year, or inorganic fertilizer NPK+Mg (N 12%, P 12%, K 17%, Mg 2%) at a rate of 4.2 t•ha^-1 per year. Their effects were compared with no fertilizer application (control). Vegetative growth, moment of flowering, number of flowers and fruit yield did not differ significantly among the organic treatments and the control. However, inorganic fertilizer application significantly enhanced growth, flowering moment, number of flowers and fruit yield in comparison with organic or no fertilizer application. Inorganic fertilizer hastened flowering and fruiting by 2-4 and 4-6 weeks, respectively. Inorganic fertilizer doubled fruit yield, compared with plants that received organic fertilizer or no fertilizer. Consequently, inorganic fertilizer application at a rate of 4.2 t•ha^-1 was superior to 5-20 t•ha^-1 organic fertilizer for production of yellow passion fruit in southwestern Nigeria.