Survey of Soil Salinity and Sodicity in Irrigated Farmlands of Jigawa State, North West Nigeria

This study surveys the extent of soil salinity and sodicity in irrigated farmlands in Jigawa State, located in Nigeria's North West geopolitical zone. Irrigation without adequate drainage in semi-arid environments progressively concentrates soluble salts in the soil profile, and sodicity from sodium accumulation disperses clay particles, reducing permeability and creating hardpan layers that severely impair crop growth and soil physical quality. Using a systematic grid survey design, 60 irrigated farm plots in three irrigation schemes in Dutse, Hadejia, and Kiyawa local government areas were sampled at 0 to 20 and 20 to 40 cm Soil Sciencehs. Soil electrical conductivity was measured on saturated paste extracts, sodium adsorption ratio and exchangeable sodium percentage were calculated, and pH, texture, and calcium-to-magnesium ratios were determined. Findings revealed that 38 percent of sampled plots had electrical conductivity values exceeding 4 dS/m, classified as saline, while 22 percent had exchangeable sodium percentages above 15 percent, indicating sodic status. Combined saline-sodic conditions were present in 14 percent of plots. The most severely affected areas were concentrated in lower topographic positions with restricted drainage. Shallow water tables were recorded in 28 percent of plots during the wet season, indicating the critical importance of drainage management. The study recommends installation of subsurface drainage systems, application of gypsum to sodic plots, and adoption of intermittent irrigation scheduling to reduce the risk of further salt accumulation in Jigawa State irrigated lands. Keywords: soil salinity, sodicity, irrigation, Jigawa State, salt accumulation.