Dil, M., Oelbermann, M. and Xue, W. 2014. An evaluation of biochar pre-conditioned with urea ammonium nitrate on maize (Zea mays L.) production and soil biochemical characteristics. Can. J. Soil Sci. 94: 551-562. Biochar can enhance soil fertility, plant nutrient uptake and crop production. Using a potted study, we quantified the effects of adding biochar at 1 t ha^-1 (Char), biochar pre-conditioned with urea ammonium nitrate [UAN (Char )], or UAN only to a control (Contr) with no amendments on maize (Zea mays L.) biomass production, tissue carbon (C) and nitrogen (N) concentrations, N uptake (NU), N utilization efficiency (NUtE), and soil chemistry and biology in coarse-, medium- and fine-textured soils over 6 wk. Soil pH decreased (P<0.05) in Char and UAN treatments for all soil textures. Soil organic carbon (SOC) increased (P<0.05) in the coarse and medium textured soil in Char and Char treatments. Soil ammonium and soil nitrate were different (P<0.05) among treatments; increasing or decreasing depending upon soil texture. Soil microbial biomass C was lowest (P<0.05) in the UAN treatment for all soil textures. Soil potential microbial activity was significantly greater in the coarse-textured soil in only the Char and Char treatments. Maize biomass, tissue N concentration, and NU increased (P<0.05) in soils amended with Char or UAN only. NUtE was lower (P<0.05) in Char and UAN treatments in the coarse- and medium-textured soils, but this was reversed for the fine-textured soil.