Land Use Change and Its Impact on Soil Carbon Pools: A Case Study of Teaching & Research Farm, Malete and Sobi Forest, Ilorin

Abstract

Land use change has emerged as a significant environmental concern, particularly in terms of soil carbon pools and ecosystem sustainability. This study investigated the impact of land use change on soil carbon pools through a comparison of soils from the Teaching and Research Farm, Malete (cultivated land) and the Sobi Forest, Ilorin (undisturbed forest land). Soil samples were collected at three depths (0–20 cm, 20–40 cm, and 40–60 cm) and analysed for particle size distribution, pH, electrical conductivity, bulk density, organic and inorganic carbon, and labile and non-labile carbon fractions. Results showed that forest soils had a sandy clay loam texture with lower bulk density (0.86 – 1.10 g/cm³) and higher organic carbon (0.24 -0.82 %), whereas cultivated soils had a sandy loam texture with higher bulk density (1.08–1.26 g/cm³) and lower organic carbon (0.14 -0.48 %). Total carbon was significantly higher in forest soils (7.46 % at 40–60 cm) compared to cultivated soils (5.65 % at 40–60 cm). Labile carbon also followed this pattern, with forest soils recording 1.66 mg/g at the surface layer versus 1.24 mg/g for cultivated soils. These findings highlight that forest-to-agriculture conversion leads to soil carbon depletion, structural degradation, and potential increases in atmospheric CO₂. The study underscores the importance of sustainable land management practices to preserve soil health and mitigate climate change