Assessment of Carbon Farming Practices as a Sustainable Strategy for Reducing Environmental Degradation and Enhancing Soil Fertility in Benue State, Nigeria

Benue State, known as the Food Basket of the Nation, faces accelerating environmental degradation driven by deforestation, bush burning, continuous cropping, and soil erosion. Soil organic carbon (SOC) levels in many parts of the state have declined to below critical thresholds, with recent field assessments reporting organic carbon values of 0.52% to 0.87% in upland soils, well below the 1.1% threshold identified for tropical soils. This quantitative study assessed five carbon farming strategies agroforestry, conservation tillage, cover cropping, biochar amendment, and integrated crop-livestock composting for their effectiveness in reducing environmental degradation and enhancing soil fertility in Benue State. A mixed-methods quantitative design was adopted, involving soil sampling across 6 sites in Makurdi, Otukpo, and Logo LGAs (n=360 soil samples) and a structured survey of 384 smallholder farmers. Soil physicochemical analysis, remote sensing estimation of erosion, and econometric modeling (Multiple Linear Regression and ANOVA) were employed. Results indicate that biochar amendment increased SOC by 39%, total nitrogen by 17.67% to 27.03%. Multiple regression showed that adoption of carbon farming explained 68.4% of variance in soil fertility index (R² = 0.684, p < 0.001). Erosion modeling using Revised Universal Soil Loss Equation (RUSLE) in Northern Makurdi estimated sediment yield between 0 to 48 ton with severe erosion affecting 34% of the area. The study concludes that scaling agroforestry, biochar from palm kernel and maize residues, and cover cropping can reduce erosion and improve yields, while contributing to Nigeria's carbon sequestration potential under the Global Soil Organic Carbon Sequestration Potential Map (GSOCseq).