Kenya Agricultural Lime Messaging Trial 2018
KEN -17 -1492Last modified on December 19th, 2025 at 10:19 am
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Abstract
One Acre Fund (OAF) is an agricultural service provider that supports smallholder farmers in Africa in accessing agricultural inputs, training, and markets, to help the farmers increase their harvests and income. PxD and OAF began collaborating in 2016 on efforts to increase adoption of agricultural inputs and improve OAF operations in Kenya and Rwanda.
In 2017, PxD and OAF conducted a randomized trial “Kenya Agricultural Lime Messaging Trial 2017” that demonstrated SMS messages significantly increased the adoption of agricultural lime by smallholder farmers in western Kenya. Building on these findings, this follow-up trial aimed to validate the 2017 results and to (a) verify that SMS messages continue to increase lime uptake, (b) test whether referencing peer farmers who previously adopted lime could promote adoption through social learning, and (c) test the relative effectiveness of different SMS framings and message repetition on farmer adoption behavior. We used a multi-component randomized trial to test these hypotheses with farmers in previously studied districts and new districts. The sample was drawn from OAF’s core program, with randomization at the individual level, stratified by district. SMS messages were delivered during the input-adoption period.
The results confirm that SMS messages increased lime adoption, and provide evidence supporting the effectiveness of digital outreach at scale. While differences between specific message framings and social learning nudges were not statistically significant, the results of the experiment suggest that message content and repetition may influence adoption behavior and offer valuable insights for refining future campaigns. -
Status
Completed
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Start date
Q3 Sep 2017
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Experiment Location
Kenya
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Partner Organization
One Acre Fund (OAF)
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Agricultural season
Short Rains
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Experiment type
Impact Evaluation
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Sample frame / target population
OAF farmers in Hamisi, Kakamega South, Kakamega North, Mumias, and Nambale
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Sample size
30,000
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Outcome type
Input adoption
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Mode of data collection
Phone survey, Partner administrative data
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Research question(s)
1. Can SMS messages increase the adoption of lime and extra calcium ammonium nitrate (CAN) fertilizer from OAF?
2. Are farmers more likely to adopt lime if we put them in touch with another farmer who has used lime?
3. Which message framings are most effective and what is the ideal number of messages to send? -
Research theme
Message framing, Message timing and frequency, Social learning
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Research Design
The project had three main components.
First, farmers from the same five districts as used in the Kenya Agricultural Lime Messaging Trial 2017 were randomized at the individual level, stratified by district, to either receive (treatment) or not receive (control) two SMS message streams. The first message stream, as in the 2017 trial, encouraged farmers to adopt lime. The other message stream emphasized the adoption of extra CAN fertilizer.
Second, a subset of farmers who had not previously adopted lime were randomly assigned to receive social learning nudges with information about “resource farmers”, who were farmers from their site who purchased lime from OAF for the 2017 season. Farmers were provided with the resource farmer’s name and phone number.
Third, approximately 180,000 OAF farmers in other districts outside the original five were sent randomly assigned SMS lime promotion messages encouraging the farmers to adopt lime; the messages were varied in framing (basic, highlighting yield increases, encouraging experimentation, making social comparisons, and promoting self-efficacy) and repetitions (1 to 5 messages).
For further information on the previous trial, see Kenya Agricultural Lime Messaging Trial 2017
For further information on PxD’s lime work , see Fabregas et al., 2024.
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Results
In the first component, SMS messages increased lime adoption by an estimated 2.2 percentage points (pp), which was a 9% increase over the control mean of 24%. The other message stream encouraging farmers to purchase extra CAN from OAF resulted in a 0.9 pp increase in CAN adoption over the control mean of 14%, and also increased lime adoption.
In the second component, there was a small positive increase, estimated at 1 pp, in the likelihood of lime adoption by farmers who were provided with the resource farmer’s name and phone number, but this result is not statistically significant.
In the third component, of the messages tested, the most effective was the increased-yield message, which increased lime purchase by 3.4 pp. However, the differences between framings are not significant—no specific message was significantly better than the basic message at the 5% level. Messages framed about the recipient were more effective than messages framed about the recipient’s family or neighbors. One message on its own had little effect. A second message had large significant effects, and the effects of subsequent messages were smaller and not significant.