The program convinced seed farmers to adopt pit planting, leading to increased yields for these farmers. While technology adoption by non-seed farmers was low across all groups, the Complex villages exhibited the largest increases in adoption relative to comparison villages. Results from the Geo Treatment group suggested similar but inconclusive increases in adoption.
The program increased the likelihood that seed farmers across all groups adopted the technologies. Compared to shadow seed farmers, or those farmers who would have been chosen as seed farmers under the selection methods used in the other villages , actual seed farmers were 25.1 percentage points more, or more than four times as likely, to adopt pit planting in the first year. Compared to shadow farmers, seed farmers who adopted pit planting experienced a 44.9 percent increase in maize yield. Moreover, differences in yields were largest during low-rainfall conditions, an important resiliency feature of the technology.
Trained seed farmers were also 13 percentage points more likely to use CRM in the first year, but adoption dropped in the second year among both actual and shadow seed farmers . This drop-off indicates that the technology may not have been well suited for these farmers . Thus, only pit planting adoption is discussed below.
While there was no difference in pit planting adoption during the first season between the network-targeted villages and comparison villages , adoption was significantly higher in network-targeted villages in seasons two and three. In season two, adoption rates increased by 61.4 percent and 79.5 percent in Simple and Complex villages respectively, compared to comparison villages where the adoption rate was 4.4 percent .
The increase in adoption in network-targeted villages was largely driven by farmers who had links to both trained seed farmers , suggesting that the complex social network model was more effective than the simple model. Farmers who had connections to both were 31.7 percent more likely to have heard about pit planting in season one, and 88.6 percent more likely to adopt it in season two, compared to farmers with no connections.
These results demonstrate that selecting seed farmers based on a complex social network model was most effective in increasing pit planting adoption. Further research is needed on other simple and inexpensive procedures that could replicate the results of the successful but data-intensive and expensive social network modeling approach.
1 World Bank Data Bank, "Malnutrition Prevalence, Height for Age (% of children uder 5)", 2010. <http://data.worldbank.org/indicator/SH.STA.STNT.ZS>