The effect of Ca2+/Mg2+ on the aggregation process of soil colloids with different alkalization degrees

Abstract

Inorganic cations’ types are crucial to the formation of soil colloid aggregates. However, there are few studies on the effects of inorganic cations on the aggregation process of alkalized soil colloids. In this study, soil inorganic colloids with different alkalization degrees were prepared, and the effects of inorganic cations on soil colloid aggregation under different electrolyte concentrations were studied by the dynamic light scattering method. The results showed that for soil colloids with different alkalization degrees, when the electrolyte concentration was the same, the activation energy of Mg2+ involved in the reaction was significantly higher than that of Ca2+, indicating that the ion species had a significant effect on soil colloid aggregation under the same valence state. Most importantly, decreasing the electrolyte concentration increases the difference in activation energy (ΔE) between the same two cations (ΔEMg − ΔECa), and the increase in soil alkalinity increases the value of ΔEMg − ΔECa. This study provides a reference for understanding the aggregation and interaction of inorganic colloids in alkaline soil, and the development of agriculture in arid areas.