Sodic Calcareous Soil Reclamation as Affected by Water Chemical Composition and Flow Rate

Abstract

AbstractSodic 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 CaCO3 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 CO2‐enriched TW at a flow rate of either 11.5 or 50 mm h‐1. The effluent from the columns was collected continuously, and its chemical composition was analyzed. When DW was used, CaCO3 dissolution was the main source (85%) for replacing exchangeable Na. When TW was used, 80% of the (Ca2+ + Mg2+) 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 (Ca2+ + Mg2+) from CaCO3 and the longer time available for Ca2+ diffusion into soil aggregates. The CO2‐enriched TW was the most favorable treatment for CaCO3 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 CaCO3 in the soil, providing management conducive for CaCO3 dissolution is used.