Soil Drainage Classes and Their Influence on Crop Production in Edo State, South South Nigeria

This study examines soil drainage classes across different land units in Edo State, located in Nigeria's South South geopolitical zone, and evaluates their influence on the selection and productivity of food crops. Drainage status is a fundamental soil property that determines oxygen availability for roots, the persistence of reducing conditions, trafficability of farmland, and the susceptibility of crops to waterlogging, making it a key criterion in land use planning across the wet tropical environment of Edo State. Using a descriptive soil survey and land use assessment design, drainage classes were assessed on 45 field sites across Orhionmwon, Esan West, and Akoko-Edo local government areas. Drainage class was assigned by field morphological criteria including profile colour, mottling pattern, and presence of gleying. Soil texture, organic carbon, and pH were measured as supplementary parameters. Farmer crop choices on each drainage class were documented by interview. Findings revealed five drainage classes across the survey area, with imperfectly and poorly drained soils occupying 35 percent of the surveyed landscape, predominantly in low-lying valley areas. Farmers on imperfectly drained soils predominantly planted cassava and yam using mound cultivation to elevate root zones above the seasonal high water table. Poorly drained soils were largely used for dry-season rice cultivation. Very poorly drained sites were generally uncultivated. The study provides drainage-based land use guidance for Edo State and recommends shallow drainage channels and raised-bed systems for agricultural use of imperfectly drained soils. Keywords: soil drainage, land use, Edo State, waterlogging, soil survey.