Sustainable intensification amongst Ghana's pineapple farmers: the complexity of an innovation determines the effectiveness of its training

To foster the adoption of sustainable intensification practices amongst Ghana's farmers, they are widely promoted through training sessions provided by development organizations, companies, and the public extension service. We investigate whether these training sessions are effective and find that they are effective only for the diffusion of organic fertilizers but not for mulching. We suggest that this comes from the complexity of the innovations. Mulching is one of the simplest sustainable intensification technologies. It diffuses easily through peer learning and, after an initial training delivered to a critical mass of farmers, does not require training anymore. The use of organic fertilizers, in contrast, requires more specific knowledge and adaptation, which limits the effectiveness of peer learning and increases the effectiveness of training. This suggests that to achieve a widespread diffusion of sustainable intensification amongst Ghana's farmers, training sessions should focus on those practices that are complex and thus difficult to learn from peers.