Assessment of Soil Fertility Status on Irrigated Wheat Farms in Kano State, North West Nigeria

This study assesses the soil fertility status of irrigated wheat farming plots in Kano State, located in Nigeria's North West geopolitical zone. Wheat production under dry-season irrigation in the Kano River Irrigation Project and smaller private irrigation schemes is an important food security and commercial farming activity, but the intensive nature of irrigated wheat production raises sustainability questions about long-term nutrient depletion and soil chemical changes. Surface (0 to 20 cm) and subsurface (20 to 40 cm) samples were collected from 35 irrigated wheat plots in Kura, Bunkure, and Wudil local government areas. Samples were analysed for pH, electrical conductivity, organic carbon, total nitrogen, available phosphorus, exchangeable potassium, calcium, magnesium, and sodium, cation exchange capacity, and exchangeable sodium percentage. Results were compared against critical threshold values for wheat production. Findings revealed that 57 percent of sampled plots had organic carbon below 0.8 percent, 49 percent had available phosphorus below the critical level of 12 mg/kg for wheat, and 34 percent had pH values below 6.2, limiting phosphorus and potassium availability. An emerging concern was sodium accumulation in 22 percent of plots, with exchangeable sodium percentage approaching sodic thresholds in the oldest irrigated plots. The study recommends soil amendment with sulphur or gypsum where sodicity is developing, balanced NPK fertilisation with phosphorus emphasis, and regular organic matter inputs to maintain fertility in Kano State irrigated wheat production. Keywords: soil fertility, irrigated wheat, Kano State, soil chemical properties, sustainability.