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Kenya Agricultural Lime Messaging Trial 2017

KEN -16 -1490

Last modified on October 29th, 2025 at 12:04 pm

    Basic Information

  • Abstract
    One Acre Fund (OAF) is an agricultural service provider that provides support for smallholder farmers in Africa to access agricultural inputs, training, and markets, to help the farmers increase their harvests and income. PAD and OAF began collaborating in 2016 on efforts to increase adoption of agricultural inputs and improve OAF operations in Kenya and Rwanda. Prior to 2016, less than 3% of OAF clients in Western Kenya purchased agricultural lime from OAF. To increase take-up, OAF designed a phone-based extension pilot that consisted of six rounds of text messages targeting clients who had signed up for the OAF package during the previous season in a selected district of Western Kenya.

    The objective of the experiment was to evaluate the impact of SMS messages on lime adoption by farmers. The study tested whether more detailed, locally customized messages—containing site-specific information about soil acidity, lime dosage, total cost, and expected yield gains—would lead to higher adoption compared to simpler, generic messages. We tested this hypothesis by randomizing two different formats for SMS messages sent to farmers in a selected district of western Kenya, starting in 2016 to lead up to the period when farmers had to decide whether to request inputs from OAF for the long rainy season 2017. A control group of farmers received no messages.

    The SMS messages significantly increased lime adoption by over 3 percentage points (pp), which is a 30% increase relative to the 10% control mean. Customized messages produced slightly higher effects than general messages. Adoption patterns were consistent across administrative and phone survey data.
  • Status
    Completed
  • Start date
    Q3 Sep 2016
  • Experiment Location
    Kenya
  • Partner Organization
    One Acre Fund (OAF)
  • Agricultural season
    Long Rains

    • Research Design

  • Experiment type
    Impact Evaluation
  • Sample frame / target population
    OAF farmers in Nambale
  • Sample size
    4,884
  • Outcome type
    Input adoption
  • Mode of data collection
    Phone survey, Partner administrative data
  • Research question(s)/hypotheses
    1. Can SMS messages increase the purchase of lime from OAF?
    2. Do messages with more specific information about local soil conditions perform better?
  • Research theme
    Message framing, Social learning
  • Research design notes

    OAF and PAD collaborated to test the effectiveness of SMS-based extension messages that promoted the adoption of lime by smallholder farmers in western Kenya. The intervention was designed as a randomized controlled trial with two treatment arms and one control group.

    Control group: Did not receive any messages.

    Broad message treatment group: Farmers received simple SMS messages encouraging them to use lime, and providing a toll-free number for more information. The message read: “Hello [name], Your soil is acidic: Use lime to reduce acidity and increase yields. Call xxx-xxxx.”

    Specific message treatment group: Farmers received more detailed, customized messages. These included locally relevant information, such as the level of soil acidity measured in their area, the recommended quantity of lime, the estimated total cost, and the expected yield improvement. The message read: “Hello [name], Your soil is [highly/moderately] acidic. We recommend [amount] kg of lime per acre at [total cost] Ksh. Use lime to reduce acidity and increase yields by [percentage]%. Call xxx-xxxx.” Customized messages were based on soil tests that had previously been conducted in the region.

    A total of 4,884 farmers were included in the study. Of these, 3,325 were randomly assigned to one of the two treatment groups and received SMS messages, while 1,559 farmers served as the control group and did not receive any messages. The same SMS messages were delivered six times between August and September 2016—before the OAF input contract signing period—at a time when farmers had to decide whether to request inputs from OAF for the following 2017 season.

    For further information, see Fabregas et al., 2024.

    • Results

  • Results
    The messages significantly increased lime adoption by more than 3 pp, an increase of 30% against the control mean of only 10%. Point estimates were higher for the more specific messages than for the broad messages. Comparing administrative and survey data, we see consistent results. Adoption measured via a phone survey gives slightly higher point estimates than when adoption is measured via the administrative data on input purchases from OAF—possibly due to a combination of reporting biases and purchases of lime from other suppliers. The SMS messages made no difference in whether the farmers had heard of lime, likely because lime was already well known as 80% of control farmers had heard of it.

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