Pakistan Journal of Biological Sciences1028-88801812-5735Asian Network for Scientific Information10.3923/pjbs.2021.90.98B. IrenOtobong EdieneVictoria F. 12021241Background and Objective: The use of biochar, a charred organic material, is becoming a sustainable technology that leads to the improvement of highly weathered tropical soils. A study was conducted at the Teaching and Research Farm of the University of Calabar to compare the effects of integrated use of Biochar (B), Poultry Manure (PM) and urea on the pH and microbial properties of soil-grown with Amaranthus cruentus. Materials and Methods: A total of 15 treatments consisting of a sole and combined use of biochar, poultry manure, urea and control were fitted on a randomized complete block design with 3 replications. The organic amendments were applied 2 weeks before sowing while urea was applied 2 weeks after sowing. Composite soil samples (0-15 cm) were taken before and after the experiment for pH and microbial analysis. Results: Soil pH was raised from a strongly acidic level to values ranging from 5.73-6.8 (moderately acid-slightly acid, respectively) pH level after the experiment with the highest obtained in Full B+½PM amended soil. The fungal population was maximum in PM (sole and combinations) (18×103-20×103 CFU g1) and minimum in sole biochar and control (×10×103 CFU g1). The bacterial population exhibited a similar trend with the maximum value in PM (sole and combinations) (98×106-148×106 CFU g1) and minimum in control (×36×106 CFU g1). Conclusion: This suggests that biochar addition alone did not cause any apparent alteration to the microbial population and diversity compared to its complementary use.]]>Foereid, B.,201553944Enders, A., K. Hanley, T. Whitman, S. Joseph and J. Lehmann,2012114644653Smith, J.L., H.P. Collins and V.L. Bailey,20104223452347Cayuela, M.L., M.A. Sanchez-Monedero, A. Roig, K. Hanley, A. Enders and J. Lehmann, 20132O emissions? ]]>2013Song, X., G. Pan, C. Zhang, L. Zhang and H. Wang,20162016Lehmann, J. and M.A. Rondon,20052005pp: 517-530pp: 517-530Rees, F., M.O. Simonnot and J.L. Morel,201465149161Novak, J.M., K.B. Cantrell, D.W. Watts, W.J. Busscher and M.G. Johnson,201414330343Chintala, R., J. Mollinedo, T.E. Schumacher, D.D. Malo and J.L. Julson,201460393404Glaser, B., L. Haumaier, G. Guggenberger and W. Zech,2001883741Rondon, M.A., J. Lehmann, J. Ramirez and M. Hurtado,2007Phaseolus vulgaris L.) increases with bio-char additions.]]>43699708Van Zwieten, L., S. Kimber, S. Morris, K.Y. Chan and A. Downie et al.,2010327235246Biederman, L.A. and W.S. Harpole,20135202214Soil Survey Staff,19992nd Edn.,Iren, O.B., C.J. Ijah, D.O. Asawalam and V.E. Osodeke, 2016Amaranthus cruentus in a rainforest ultisol, Nigeria. ]]>15257Jones, J.B.,20011st Edn.,pp: 384pp: 384Paul, E.A. and F.E. Clark,19891989pp: 81-84pp: 81-84Zuberer, D.A.,19941994pp: 805-820pp: 805-820Chair, R.W.W., S. Angle, P. Bottomley, D. Bezdicek, S. Smith, A. Tabatabai and A. Wollum, 1994Harrigan, W.F. and M.E. McCance, 19788th Edn.,Gaskin, J.W., C. Steiner, K. Harris, K.C. Das and B. Bibens,20085120612069Baldock, J.A. and R.J. Smernik,2002Pinus resinosa (Red pine) wood.]]>3310931109Novak, J.M., W.J. Busscher, D.L. Laird, M. Ahmedna, D.W. Watts and M.A.S. Niandou,2009174105112Joseph, S.D., M. Camps-Arbestain, Y. Lin, P. Munroe and C.H. Chia et al.,201048501515