Sodic soils exhibit poor physical conditions that adversely influence water and air movement, soil erodibility, and plant growth. This study investigated the efficiency of naturally occurring CaCO 3 in reclaiming a sodic loess soil (Calcic Haploxeralf) with an exchangeable sodium percentage of 16. Soil columns (50 or 100 mm high) were leached with distilled water (DW), 1 dS m -1 tap water (TW), or CO 2 -enriched TW at a flow rate of either 11.5 or 50 mm -1 . The effluent from the columns was collected continuously, and its chemical composition was analyzed. When DW was used, CaCO 3 dissolution was the main source (85%) for replacing exchangeable Na. When TW was used, 80% of the (Ca 2+ + Mg 2+ ) for reclaiming the sodic soil came from the leaching solution. The slow water flow rate (11.5 mm h -1 ) improved reclamation by ∼30%, probably due to the higher concentration of (Ca 2+ + Mg 2+ ) from CaCO 3 and the longer time available for Ca 2+ diffusion into soil aggregates. The CO 2 -enriched TW was the most favorable treatment for CaCO 3 dissolution and thus the most efficient for soil reclamation. Our results suggest that reclamation of sodic soils can be accomplished by means of the naturally occurring CaCO 3 in the soil, providing management conducive for CaCO 3 dissolution is used.