Assessment of Soil Organic Carbon Status in Smallholder Farms in Enugu State

This study assesses the status of soil organic carbon in smallholder crop farms in Enugu State, South East Nigeria, and examines the farming practices associated with different SOC levels. Soil organic carbon is a foundational indicator of soil health and productivity, influencing water retention, nutrient cycling, structural stability, and biological activity. In the intensively cultivated smallholder farming landscape of Enugu State, continuous cropping without adequate organic matter inputs has raised concerns about progressive SOC depletion. This study collects soil samples from 60 smallholder farms in Igbo-Eze North, Udi, and Nkanu East local government areas at 0 to 15 centimetre depth during the dry season. SOC concentration is measured using the Walkley-Black wet oxidation method. A survey of farmer practices including fallow frequency, organic matter addition, and tillage intensity accompanies the soil sampling. Correlation analysis links farm management practices to SOC levels. Findings reveal that average SOC in sampled farms is 1.62 percent, with a range from 0.83 to 2.91 percent. Farms maintaining regular fallow periods show SOC levels 38 percent higher than continuously cropped farms. Organic matter application through crop residue retention and compost use is strongly correlated with higher SOC. Tillage intensity shows a significant negative relationship with SOC. The study concludes that SOC depletion is a significant threat to long-term productivity in Enugu State smallholder farms. It recommends agroforestry integration and minimum tillage promotion as priority SOC management strategies.

Keywords: soil organic carbon, smallholder farms, Enugu State, soil health, management practices.