FAOSTAT (2011) Food and Agricultural Organization World Balance Sheet.
 Ogunlade, M.O. and Aikpokpodion, P.O. (2010) Physicochemical Properties of Selected Soils in Three Cocoa Growing Ecologies of Nigeria. Proceedings of the 44th Annual Conference of Agricultural Society of Nigeria, Lautech, 88-110.
 Akanbi, O.S.O., Ojeniyi, S.O., Famaye, A.O., Ipinmoroti, R.R., Ibiremo, O.S., Oloyede, A.A., Taiwo, N., Aderolu, I.A. and Orisasona, T.M. (2013) Utilization of Ashed Cocoa Pod Husk and Urea Fertilizer on Growth and Dry Matter Yield of Coffee on Alfisol in Ibadan. Nigerian Journal of Soil Science, 23, 10-16.
 Akanbi, O.S.O., Ojeniyi, S.O., Famaye, A.O., Oloyede, A.A., Oyewumi, I.K., Ayegbonyin, K., Adejobi, K.B. and Idrisu, M. (2014) Soil Nutrients and Cocoa Seedlings Performance as Influenced by Plant Residue Ash and NPK Fertilizer Addition on a Depleted Soil in Ibadan. International Research Journal of Agricultural Science and Soil Science, 1, 1-4.
 Ibiremo, O.S. and Fagbola, O. (2008) Effect of Phosphate Fertilizer and Arbuscular Mycorrhizal Fungi Inoculation on the Growth of Cashew Seedlings in Two Soils in Nigeria. Nigerian Journal of Soil Science, 18, 148-156.
 Ibiremo, O.S., Akanbi, O.S.O., Oloyede, A.A and Adebowale, L.A. (2012) Evaluation of NPK Fertilizer Formulations on the Growth and Dry Matter Yield of Coffee Seedlings in Ibadan, South-Western, Nigeria. Nigerian Journal of Soil Science, 23, 22-26.
 Moyin-Jesu, E.I. (2007) Use of Plant Residues for Improving Soil Fertility, Pod Nutrients, Growth and Pod Weight of Okra (Abelmoschus esculentum L.). Bioresource Technology, 98, 2057-2064.