Management of Waterlogging and Drainage for Rice Production in Ebonyi State Lowlands, South East Nigeria

This study evaluates waterlogging conditions and develops professional drainage management options for lowland rice production in Ebonyi State, located in Nigeria's South East geopolitical zone. Ebonyi State is designated as Nigeria's rice production capital, and the lowland valley bottom soils used for rice production face complex waterlogging and drainage challenges that affect planting schedules, variety selection, and yield outcomes. Using a professional hydropedological assessment design, 25 lowland rice paddock sites across Abakaliki, Ivo, and Ohaukwu local government areas were monitored for water table Soil Scienceh, soil redox potential, pH, and iron and manganese concentrations during one full growing season. Soil morphological indicators of drainage class were documented and drainage coefficients were estimated from soil hydraulic conductivity measurements. Geographic information analysis was used to identify drainage problem zones across the paddy landscape. Findings revealed that 40 percent of monitored paddocks experienced prolonged water table emergence above 30 cm for more than 70 consecutive days, limiting root aeration and creating ferrotoxicity risk. Iron concentrations in floodwater exceeded 300 mg/L at peak flooding in 35 percent of sites, associated with significant yield depression. The study recommends the construction of controlled drainage structures to allow drainage regulation, adoption of floating-type and iron-tolerant rice varieties in high-ferrotoxicity sites, and surface levelling of paddocks to improve water distribution uniformity. A drainage investment prioritisation plan for Ebonyi State lowland rice schemes is provided. Keywords: waterlogging, drainage, lowland rice, Ebonyi State, ferrotoxicity.