Assessment of Impact of Land Uses on Soil Carbon Stock and Quality

Deforestation due to urbanization depletes soil quality and increases greenhouse gas emission into the atmosphere leading to climate change. Hence, agroforestry in terms of plantation is an appropriate system for mitigating atmospheric gasses and increasing soil quality. Forest ecology is estimated to store about 70% of above and below organic carbon. This study aimed to assess the impact of land uses on soil carbon stock and quality in an ecosystem. Among all the land uses, natural forest have high porosity, exchangeable bases, organic carbon, total nitrogen, carbon stock, micronutrients, and soil quality than other land uses. Mixed plantation was reported to have low bulk density than other monoculture plantation, such as teak, gmelina, eucalyptus, and acacia and were attributed to high quantity of litter falls under mixed plantation as compared to low litter fall under monoculture plantation sites. Mixed plantations were significantly higher in organic carbon, litter fall, and exchangeable bases and soil quality than soils under monoculture plantations. Soil under teak, eucalyptus, and acacia were characterized with low moisture content, high bulk density, low organic carbon, and potassium content. The low organic carbon in teak was attributed to the high rate of mineralization of litter. Teak was reported to have higher litter fall and faster rate litter decomposition than eucalyptus, thus contributing higher nitrogen and phosphorus to soil. Teak contributes higher extractable Fe and Cu relative to other forest trees. Gmelina was reported to contribute higher organic carbon to soil than teak, while acacia have the lower nitrogen than other tree species. Higher bulk density and low nutrient reserve, which result to poor quality predominates under elephant grass and farmland, were ascribed to continuous disturbance leading to low organic carbon in the land uses. Sustainable land use management is required to increase soil carbon stock and quality for sustainability.