Circular economy pathways for woodworking waste: assessing the socio-economic and agronomic potential of sawdust and wood offcuts as organic soil amendments for smallholder farmers

The sawmill and woodworking industry in South East Nigeria generates large volumes of sawdust and wood offcuts, often burned or dumped. This is creating environmental hazards while wasting organic resources. Rising synthetic fertilizer costs and declining soil organic carbon among smallholder farmers highlight the need for alternatives. This study evaluates composted sawdust blended with poultry manure (3:1 v/v) and wood offcuts as a circular economy pathway linking waste management and agricultural productivit. The study employed a Randomized Complete Block Design field trial across communities near wood-processing clusters, complemented by farmer surveys (n = 260) and sawmill operator interviews. The results show composted hardwood and softwood sawdust improved soil organic carbon by 38–52%, enhanced moisture retention, and increased nitrogen, phosphorus, and potassium. Maize yields under compost treatment (10 t ha−1) reached 4.60 t ha−1, comparable to half-dose NPK but at 61% lower input cost. Surveys reveal strong willingness-to-adopt among farmers near sawmills, though concerns about soil acidity and pest risks remain barriers. The study introduces a ‘Proximity-Adoption-Livelihoods’ nexus. This offers a scalable model for youth-led composting enterprises. It is also informing agricultural extension and waste policy in sub-Saharan Africa.