Monitoring salinization along Lugu main canal of Wurno Irrigation Project

Abstract

A study was conducted to monitor salinity development along Lugu main canal of Wurno Irrigation Project. The objective of the study was to determine the current salinity levels at different soil depths. Four transects were randomly selected and soil samples were taken at two sampling points in each transect at 0 - 15, 15 - 30 and 30 - 45 cm depths. Soil pH, EC, CEC and exchangeable bases (Ca²⁺, Mg²⁺, K⁺ and Na⁺) were determined while sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) were calculated from the results. The result shows that the surface soils (0 - 15 cm) were saline - sodic while the lower depths (15 - 30 and 30 - 45 cm) had no threat of salt accumulation. Continuous monitoring of the quality of the irrigation water and reclamation through substitution of Na⁺ from the exchange complex with Ca²⁺ using gypsum (CaSO₄. 2H₂O) and subsequent leaching out of the salt with high quality irrigation water along with the provision of an efficient drainage system were recommended for the surface soils.