Soil Texture and Structure Assessment Across Different Ecological Zones in Kano State, North West Nigeria

This study assesses soil texture and structural properties across three distinct ecological zones in Kano State, located in Nigeria's North West geopolitical zone. Kano State spans a gradient from the Sahel in the north through the Sudan savanna to the transitional zone in the south, creating marked differences in soil parent material, weathering intensity, and organic matter inputs that influence soil texture and structure, which in turn determine water-holding capacity, susceptibility to erosion, and crop productivity potential. Using a descriptive soil survey design, representative profiles were described and sampled in three ecological zone transects, with three pedons per zone. Soil texture was determined by the hydrometer method, structural stability by wet sieving, bulk density by the core method, and hydraulic conductivity by the constant-head method in the laboratory. Findings revealed that northern Sahel soils were predominantly sandy (greater than 80% sand), loose-structured, and had very low hydraulic conductivity due to low organic matter content. Southern transitional zone soils were loamier, with better aggregate stability and higher organic matter inputs from better vegetation cover. Middle Sudan savanna soils showed intermediate properties but significant surface crusting from raindrop impact during early rainfall. The study provides baseline texture and structure data for agroecological zone planning in Kano State and recommends organic matter additions and conservation tillage as priority interventions for improving structural stability in the northern Sahel zone. Keywords: soil texture, soil structure, ecological zones, Kano State, agroecological planning.