Desalinization and desodification efficiencies of phosphogypsum and leaching water in saline–sodic soils of Kessem, Ethiopia

Abstract

Abstract Soil salinity and sodicity severely limit agricultural productivity in the Awash Basin of Ethiopia, demanding innovative reclamation strategies. This study evaluated the efficiency of phosphogypsum (PG) amendment at varying loadings under intermittent leaching using pore volume for saline–sodic clay loam soils at Kessem Sugar Estate, Ethiopia. Soil columns were treated with five PG loadings (equivalent to 50%, 75%, 100%, 150%, and 200% of gypsum requirement [GR]), locally mined gypsum (100% GR), and a control, followed by six leaching rounds using nonsaline, non‐sodic water (sodium adsorption ratio = 1.15), with a total leaching depth of 33 cm. PG application at 100% GR loading and above had removed over 85% of salts, significantly reducing pH, electrical conductivity, and exchangeable sodium percentage to target levels. It also enhanced bulk density, total porosity, aggregate stability, and saturated hydraulic conductivity. Notably, desalinization and desodification trends were best described by an exponential model, providing a predictive framework for estimating leaching water requirements. These findings highlight PG as a superior amendment for reclaiming saline–sodic soils and introduce a scientifically grounded approach for optimizing reclamation practices. Field‐scale validation focusing on nutrient dynamics, rate optimization, and economic feasibility is recommended to support sustainable saline–sodic soil management in Kessem Sugar estate and similar regions.