Transitioning from linear to circular systems offers sustainable solutions for smallholder agriculture in the Global South

• Linear farming models deplete natural resources and accelerate ecosystem decline. • Immediate, low-cost wins include composting and recycling crop residues. • Medium-term investments such as basic IoT tools and cooperative training enhance efficiency. • Aspirational technologies like AI-driven precision farming and hydroponics promise transformative change. • Emerging business models indicate profitability and market viability of circular agriculture. • Persistent barriers include weak policy support, limited finance, skills shortages, and poor infrastructure. • Integrated, context-specific policies and interventions accelerate adoption of circular practices. Agriculture remains central to economies across the Global South despite lower average productivity. It provides livelihoods for much of the rural workforce and contributes a meaningful share of gross domestic product (GDP). Smallholder farmers face persistent challenges that include water scarcity, limited energy access and weak institutional support. These pressures are intensified by linear “take, use, dispose” systems that deplete natural resources and generate waste. This review synthesizes insights from over 150 studies published between 2005 and 2025 in Web of Science, Google Scholar, and Scopus and international organizations such as FAO databases to examine how circular economy (CE) interventions can enhance the sustainability of smallholder agriculture. Circular practices such as composting, vermicomposting, biochar application and Black Soldier Fly (BSF) bioconversion are already emerging in smallholder contexts. Many of these practices are implemented in silos and need integration within a coherent cross farm framework. The review also identifies a previously overlooked interdisciplinary connection between regenerative practices and digital agriculture tools such as IoT sensors and precision input systems. Used together, these approaches help smallholders reduce waste, close nutrient loops and improve input efficiency and soil health. Emerging business opportunities include localized composting and BSF enterprises, biochar supply services and farmer led cooperatives that offer climate smart products. High potential options such as hydroponics and aquaponics remain constrained by infrastructure and energy demands and require localized adaptation. The literature suggests that investors can play a catalytic role when risk adjusted returns are clear. CE interventions must therefore deliver environmental impact and financial viability to engage farmers and attract capital. To accelerate adoption, future research and policy should address financing barriers, capacity gaps and policy misalignment through microcredit schemes, peer led demonstration farms and co-developed policy roadmaps. This review advances that CE practices in smallholder agriculture across the Global South are not optional but essential, offering a pathway to greater resource efficiency, resilience, and economic viability than conventional linear systems. The urgency lies in the accelerating threats of resource depletion, environmental degradation, and climate change which, if unaddressed, will undermine smallholder livelihoods and jeopardize regional food security.