Land Use Changes and Sustainable Land Management Practices for Soil Carbon Sequestration in Sub-Saharan African Agro-ecosystems

Land use plays an important role in the global system. It alters in response to changing human needs driven by an array of socio-economic, technological, political, and environmental factors. However, the rate of land use change in sub-Saharan Africa (SSA) remains alarming due to a population that is rapidly growing at the rate of 2.6% annually and technological advances leading to the transformation of the land surface. For example, between 2010 and 2015, the rate of forest decline was about 2.8 million ha year−1. The prominent mode of transformation has been the conversion of fragile native ecosystems (i.e., forests, woodlands, savannahs, grasslands, and steppe) into agro-ecosystems in order to fulfill the escalating demand for food, fiber, fuel, and shelter. This has had ramifications on the principal carbon (C) pools, especially the soil organic C (SOC) pool. Studies have shown that a decline in SOC stocks following deforestation in SSA can at times exceed 50%. However, the exact magnitude of SOC depletion in SSA is still uncertain owing to scarcity of reliable long-term data needed for accounting. Replenishing SOC stocks in SSA agro-ecosystems calls for adoption of a combination of appropriate sustainable land management (SLM) practices (e.g., conservation agriculture (CA) and integrated nutrient management), which can enhance the capture and storage of C in plants and soils, as well as mitigate GHG emissions and climate change. For example, soil C sequestration under CA and fertilizer use in Africa has, on average, been 0.37 Mg C ha−1 year−1and 0.63 Mg C ha−1 year−1, respectively. In this chapter, we have provided a synthesis of the impact of land use changes (i.e., conversion of forests to croplands) on the SOC pool, as well as the SLM strategies with a potential for sequestering C in SSA agricultural soils.