Smallholder farmers in sub-Saharan Africa face challenges in achieving food security. The need to identify practices that boost crop production without significantly increasing greenhouse gas (GHG) emissions is urgent. This review aims to identify such farming practices, assess their impact on GHG emissions, and propose strategies that enhance crop production and mitigate GHG emissions. Farmers often expand agricultural land, develop water harvesting and irrigation techniques, and increase cropping intensity and fertilizer use to improve crop production. However, these practices can alter carbon stocks and GHG emissions, creating a trade-off between food security and GHG mitigation. The primary source of GHG emissions in the region is the expansion of agricultural land at the expense of forests. Water harvesting and irrigation can increase soil organic carbon but can also trigger GHG emissions. Increasing cropping intensity can accelerate the decomposition of soil organic matter, releasing carbon dioxide. The use of nitrogen fertilizers can enhance soil organic carbon but can also increase nitrous oxide emissions. An integrated strategy for managing land, water, and nutrients is necessary to enhance crop production and mitigate GHG emissions. Agroforestry practices in degraded and marginal lands could serve as an alternative to expanding agricultural croplands. Proper water management through adequate rainwater harvesting and irrigation techniques, coupled with appropriate nutrient management, should be considered. A Land-Water-Nutrient Nexus (LWNN) approach can provide an integrated and sustainable solution for increasing crop production and mitigating GHG emissions. Implementing the LWNN approach faces various barriers, but these can be overcome by developing suitable technologies, disseminating them through farmer-to-farmer approaches, and formulating specific policies to address smallholder land tenure issues and encourage long-term investment.
 

Food security; Water, Land, Carbon; Greenhouse gas; sub-Saharan African