International Journal of Soil Science1816-4978xxxx-xxxxAcademic Journals Inc.10.3923/ijss.2007.301.307AkintokunA. K.AkandeG. A.AkintokunP. O.PopoolaT. O.S.BabalolaA. O.4200724The ability of thirty-one fungal strains isolated from Nigerian cultivated farmland to solubilize rock phosphate and tri-calcium phosphate (TCP) was investigated. pH, titratable acidity, available phosphorus, total phosphorus and organic acid released were analysed as a measure of solubilization ability in liquid based medium containing rock phosphate and TCP. Isolated fungal species belong mainly to the genera of Aspergillus, Penicillium, Trichoderma, Fusarium, Mucor, Ovularopsis, Tritirachium and Geotrichum. Apart from Geotrichum, all the isolates were able to solubilize phosphate rock and TCP. Phosphate solubilization was accompanied by a decrease in the pH of the medium by all the strains; however, this decrease differed significantly among isolates (p<0.05). The production of fumaric, acetic, gluconic, lactic and succinic acids accompanied solubilization of TCP, while citric, fumaric, malic and tartaric acid were detected in extracts of phosphate rock medium. Significant differences (p<0.05) were observed in the type and amount of organic acids produced by the fungi species Aspergillus terreus produced the highest amount of fumaric acid (264.45 mg/100 mL in TCP medium, while A. niger produced the highest amount of malic acid (18.20 mg/100 mL) in rock phosphate medium Succinic acid was the least produced of the acids.]]>Akinrinde, E.A., O.A. Onanuga, O.S. Bello and G.O. Obigbesan,2003417Alikhani, H.A., N. Saleh-Rastin and H. Antoun,20062873541Ames, B.N.,19668115116AOAC,199012th Edn.,Asea, P.E.A., R.M.N. Kucey and J.W.B. Stewart,1988Penicillium species in solution culture and soil.]]>20459464Bernett, H.L.,19602nd Edn.,Chien, H.S. and G. Menon,199541197209Chuang, C.C., Y.L. Kuo, C.C. Chao and W.L. Chao,2007Aspergillus niger.]]>43575584Gilman, J.C.,19752nd Edn.,Illmer, P. and F. Schinner,19924 with P-solublizing microorganisms.]]>24389395Kucey, R.M.N. and F.A. Paul,1982Vicia faba L.).]]>14407412Midgley, D.J., P.M. Letcher and P.A. McGee,2006186211217Molla, M.A.Z. and A.A. Chowdhury,198478393399Nahas, E., D.A. Banzatto and L.C. Assis,1990Aspergillus niger in vinasse medium.]]>2210971101Nahas, E.,199612567572Pradhan, N. and L.B. Sukla,20065850854Reyes, I., L. Bernier, R.R. Simard, P. Tanguay and H. Antoun,2001Penicillium rugulosum.]]>3317411746Richardson, A.E.,200128897906SAS,19894th Edn., Vol. 2,Singh, C.P. and A. Amberger,19917261269Singh, C.P. and A. Amberger,1998631316Vassilev, N., A. Medina, R. Azcon and M. Vasslev,20062877784Whitelaw, M.A.,20006999151Omar, S.A.,199714211218