AMELIORATION OF SODIC CLAY SOILS BY CRACK STABILIZATION

Abstract

An experimental laboratory simulation was used to test a new concept for the amelioration of solonetzic and other sodic clay soils. In this concept a solution of a calcium salt is injected into the open cracks at the end of a dry season. The purpose of this is to stabilize the soil material in the exteriors of the soil aggregates, thus causing incomplete and retarded closing of the cracks in the subsequent wet season. As a result of this, the downward transport of water and the leaching of salts are promoted, the aeration of the topsoil is improved, and the vertical extension of roots is facilitated. The favorable effects of the treatment on the morphology and water-transmission properties of the cracks and on the desalinization and desodication of the soil increase with an increase of the Ca concentration in the amendment solution. The results of the laboratory simulation indicate that it is worthwhile to try the new method of sodic clay soil amelioration on a field scale. On calcareous soils and soils containing soluble carbonates, strong acids or aluminum salts may be used instead of calcium salts. Also with these electrolytes, however, the success of the treatment depends on the concentration of the amendment solution used. As gypsum has only a limited solubility and more soluble calcium or aluminum salts are expensive, waste acids may have to be used.