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

Digital technologies are changing how agricultural knowledge is produced, circulated, interpreted and acted upon, but the transformation of extension and rural advisory services cannot be inferred from connectivity or service enrolment alone. This critical narrative review examines the evidence for digitally mediated advice as an intervention and as a reconfiguration of agricultural knowledge and innovation systems. Peer-reviewed conceptual studies, evaluations, systematic evidence syntheses and relevant institutional literature published primarily from 2000 to 17 August 2026 were considered, with emphasis on comparative evidence from low- and middle-income countries and conceptual contributions from broader agricultural systems. The review differentiates short-message, voice, interactive, video, platform and artificial-intelligence-supported services; assesses the progression from exposure and learning to adoption, productivity, income and sustainability; and examines inclusion, public–private coordination, professional roles, data governance and financing. Experimental and meta-analytic evidence supports modest positive average effects of some digital information interventions on agricultural practice and performance, but findings differ by modality, complementary services, outcome definition and observation period. Several trials show improvements in knowledge or practices without corresponding detectable yield changes. Evidence concerning women’s effective agency, climate resilience, environmental outcomes, sustained use and costs at scale is materially weaker than evidence concerning message reach or immediate learning. Digital systems can lower some communication costs while transferring burdens to users, field agents or under-resourced public agencies; platform dependence and opaque automated recommendations create additional governance problems. The review advances a conditional account of effectiveness in which the value of digital advice depends on actionable content, trusted interpretation, resources for implementation and accountable feedback loops. Stronger assessment requires comparisons between feasible advisory models, disaggregated outcomes, independently measured agronomic results and full life-cycle cost accounting. Digital transformation is most defensible as a selective redesign of pluralistic advisory systems rather than a universal replacement of face-to-face extension.