Digital and Participatory Extension Approaches in Vegetable Farming

Abstract

Two distinct extension traditions have shaped how vegetable farmers gain agronomic knowledge: participatory approaches that treat farmers as co-designers of innovation, and digital approaches that use mobile phones, apps, and increasingly artificial intelligence to deliver advice at scale. This review examines both traditions and the growing literature on where they intersect. Evidence from the World Vegetable Center and related participatory-design frameworks shows that the appropriate level of farmer participation depends on how ready an innovation is for local use. Evidence from digital extension programmes shows real reach and adoption gains, but also a risk that farmer-centred design intentions erode as digital platforms scale. Machine-learning tools for vegetable pest and disease diagnosis show high technical accuracy in controlled studies, but limited evidence yet on real-world farmer uptake. Digital Farmer Field Schools, which combine both traditions directly, show some of the strongest documented knowledge gains of any approach reviewed here, though evidence on their cost-effectiveness and durability over time remains thin. The review argues that combining participatory design with digital delivery, rather than treating them as substitutes, offers the most promising path for reaching vegetable farmers at both scale and relevance.