Agricultural Extension and Rural Advisory Services: Theories, Approaches, Innovation Systems and Future Directions

Agricultural extension and rural advisory services are frequently assessed by the number of farmers reached, the technologies adopted and the resulting production gains. These indicators are insufficient for determining whether advisory systems serve people whose access to information, resources and decision-making is structurally constrained. This critical narrative review examines inclusion as an institutional, relational and outcome-oriented property of advisory systems rather than a characteristic of isolated programme participants. Peer-reviewed empirical studies, methodological contributions and relevant research syntheses published primarily from 2004 to 18 August 2026 were critically examined, with earlier foundational work retained when necessary. The synthesis integrates evidence on gender and intra-household agency, participatory learning, social networks, digital advisory delivery, pluralistic governance, financing and evaluation methods. Evidence indicates that reaching a marginalised farmer does not necessarily provide that person with usable advice or the authority and resources to act upon it. Participatory and digital approaches can reduce particular information barriers, but their distributional effects depend on literacy, connectivity, facilitator quality, social position, workload and control over productive assets. Studies of farmer field schools and information interventions report context-dependent benefits, while findings on diffusion and sustained livelihood change are less consistent. Institutional pluralism expands service options but can also fragment accountability and privilege clients who can articulate demand or afford complementary inputs. The review proposes a sequential interpretation of inclusion across eligibility, contact, comprehensibility, deliberative influence, practical capability and sustained benefit. It argues for evaluation designs that distinguish contact from agency, test distributional effects within heterogeneous populations and measure service responsiveness alongside conventional adoption indicators. More credible progress will require appropriately financed public-interest functions, context-specific combinations of delivery channels and comparative evidence on whether inclusive processes alter outcomes over time.