Comparative Evaluation of Phosphorus mineralization by Bone meal and Sokoto Rock Phosphate as Fertilizers for Organic Okra ( [Abelmoschus esculentus] production

Abstract

This preliminary study investigated the responses of okra [Abelmoschus esculentus Lmoench] to Bone meal and Sokoto Rock Phosphate [SRP] as organic fertilizers. The experriment replicated four times was conducted in the screen house of the Department of Agronomy, University of Ibadan, Nigeria in a randomized complete block design,. The treatment were bone meal, rock phosphate, mineral fertilizer [NPK 15;15;15] and control [no soil additive]. All the treatment [except the control] were applied at 50kg N, 45kg P, and 40kg K/ha. The data obtained were analyzed using analysis of variance [ANOVA] and means were compared using least significant difference [LSD]. Incubation studies were also carried out on all the treatments to evaluate their rate of P release. The incubation study of the applied ferrtilizer treatments revealed that Sokoto Rock phosphate mineralized its P within 10 weeks after incubation [WAI] and in a highrer quantity than Bone meal while Bone meal commenced mineralization at 10 WAI and still showed a potential to continue to release its P after the 15WAI when the study was terminated. The yeld of okra revealed that there was no significant difference [P<0.05] in both the frresh and dry yelds of okra across the treatmens. However, considering the rate of release in the incubation study, it could be concluded that rock phosphate could support short season crop like okra while it is advisible to incorporate bone meal for about 3months in the soil before planting such crops. While combination of both the two could be suggested in raising long season crops, however, their application may not be encouraged on a sandy soil