Rabileh, M. A., Shamshuddin, J., Panhwar, Q. A., Rosenani, A. B. and Anuar, A. R. 2015. Effects of biochar and/or dolomitic limestone application on the properties of Ultisol cropped to maize under glasshouse conditions. Can. J. Soil Sci. 95: 37–47. Ultisols in the tropics are characterized by low pH and high exchangeable Al. Maize grown on them produces low yield. A study was conducted to determine changes in soil properties and their subsequent effects on maize growth, resulting from oil palm empty fruit bunch (EFB) biochar and/or dolomitic limestone application. The results show that the application of the EFB biochar improved soil fertility by increasing soil pH. The Al³ activities in the soil solution decreased exponentially with increasing rate of the biochar application. The decrease in Al in the biochar-treated soil occurred because: (1) at the rate of>5 t ha^-1, soil solution pH increased significantly, precipitating Al as gibbsite; and (2) the biochar was able to fix some of the Al by chelation. Application of the biochar alone or in combination with lime significantly improved maize growth. The critical Al³ activity for maize grown on Ultisol was 10 µM, while critical pH was 4.7–4.8. Maize grown on the EFB biochar-amended soils produced greater root length compared with that of the control. The optimal rate of EFB biochar application to improve the productivity of the Ultisol for maize production under glasshouse condition was 5–10 t ha^-1.