Sodic Soil Reclamation Using Multicomponent Transport Modeling

High contents of soluble salts accumulated in a soil can significantly decrease the value and productivity of agricultural lands. Present recommendations for reclamation are usually based only on relatively simple and often empirical relations. In this paper we give a brief overview of many unique physical and chemical factors important to reclamation contained in the one-dimensional multicomponent transport model UNSATCHEM and demonstrate its use for evaluating the reclamation of a sodic soil using various amendments and management strategies. We evaluate particular reclamation strategies based on the following considerations: (1) the quantity of water needed; (2) the quantity of amendments to be used; and (3) the time required for reclamation to be completed. Our study concentrates primarily on such chemical reactions as cation exchange, precipitation, and dissolution of solid phases (reclamation amendments) and on the effect of solution composition on the soil hydraulic properties and corresponding changes in the water flow and solute transport rates.