農業普及員による直接的技術移転とソーシャルラーニングを介した間接的技術移転

―エチオピアの農村を事例として―

抄録

The agricultural extension service is expected to help dissemination of beneficial technologies to farmers. However, agricultural extension agents have a limited capacity and thus often interact with only a limited number of farmers in their assigned area. This limitation can be alleviated if knowledge of extension agents diffuses from farmers with a direct contact with extension agents (“model farmers”) to other farmers through social learning. This paper examines effectiveness of this dissemination process, using household-level data from rural Ethiopia. In particular, we estimate the direct effect of extension agents on knowledge of model famers for two techniques, row planting and compost, and also the agents' indirect impact on knowledge of other farmers through learning from the model farmers. In addition, we investigate the effect of each of three extension agents in the region separately, assuming that how they choose model farmers affect the size of their indirect effect through social learning. We find that knowledge of row planting, a simple but surprisingly new technique in the region, spreads directly from extension agents to model farmers if the agents select farmers with large absorptive capacity as model farmers. However, the indirect effect of extension agents on knowledge of non-model farmers is either statistically insignificant or small in size, even when agents choose farmers in the center of advisory networks as model farmers. In addition, understanding of composting, a relatively complicated but more established technique in the region, is not related to direct or indirect ties with extension agents.