Catalyzing climate action: the role of circular bioeconomy in enhancing adaptation for smallholder farmers in Nigeria

Smallholder farmers in Nigeria face persistent challenges of low agricultural productivity, declining soil quality, climate-related risks, and limited access to financial and institutional resources, which undermine farm income and livelihood sustainability. Circular bioeconomy practices offer potential pathways for improving resource-use efficiency by promoting the recycling, reuse, and integration of biological resources within farming systems. However, empirical evidence on the intensity of circular bioeconomy implementation and its relationship with smallholder farm income remains limited. This study examines the implementation of circular bioeconomy practices and their association with annual net farm income among 480 smallholder maize farmers in Southwest Nigeria. The study considers intercropping, organic composting, and integrated crop–livestock systems. Primary cross-sectional data were analyzed using descriptive statistics, a negative binomial model, polynomial regression, and propensity-score matching as a robustness check. The findings reveal substantial heterogeneity in implementation intensity, which is influenced by household, farm, institutional, and environmental characteristics. Greater circular bioeconomy implementation is generally associated with higher annual net farm income, although the benefits of more complex practice combinations depend on farmers’ resource endowments, technical capacity, and institutional support. The study recommends targeted extension services, improved access to affordable credit, strengthened farmer organizations, and inclusive, context-specific support to promote sustainable and equitable circular bioeconomy transitions.