Effect of Wetting and Drying Cycles on Soil Properties under Irrigation with Water of Varying Salinity Concentration

This study examines the impact of alternating wetting and drying cycles, typical of field irrigation, on soil chemical properties under different salt concentrations. It focuses on how these cycles, combined with high thermal conditions, affect soil fertility and structure, especially in summer, The aim was to assess the effect of wetting and drying cycles on the soil's chemical properties, focusing on the influence of varying salinity levels in irrigation water,This study was conducted at five sites in Nineveh Governorate, northern Iraq, selected for soil texture variation. Surface soil samples were collected from the (0-20) cm depth, and both chemical and physical analyses were performed. Soil columns were also irrigated with well water at different salinity concentrations. Soil underwent ten cycles of wetting and drying, each lasting ten days. After the final cycle, samples were taken for chemical analysis to evaluate changes in properties such as electrical conductivity, pH, ion concentrations, calcium carbonate, and cation exchange capacity, Results indicated that wetting and drying cycles increased electrical conductivity, decreased soil pH, and raised ion concentrations. Calcium carbonate content decreased, while cation exchange capacity and structural stability increased. Organic matter remained unchanged.