Emerging Evidence on Why Soil Testing is Key to Improve Yields on Smallholder Farms in Kenya

Soil acidity problem is a significant cause of low and stagnated crop yields in Kenya, particularly for maize, which is the country’s main staple crop. But research demonstrate that few farmers test their soils or make soil management decisions based on knowledge about the condition of their soils.

To help generate evidence to bridge this gap, ICED and Feed the Future Innovation Lab for Markets, Risk and Resilience (MRR) through the USAID’s ALL-IN research grant is funding Tegemeo Institute in Kenya to conduct a research dubbed Soil Testing for Soil Acidity Management on Smallholder Farms in Kenya. The research, whose Principal Investigator is Dr. John Olwande, aims to provide policy-relevant and evidence-based insights on practical ways to encourage farmers to understand and update their knowledge about the condition of their soils and subsequently apply appropriate soil amendments.

The researchers collected soil samples from 657 smallholder farms in 120 villages in 24 wards spread across Bungoma, Kakamega, Trans Nzoia and Uasin Gishu counties. Crop Nutrition Laboratory Services Ltd (Cropnuts), Tegemeo’s partner, conducted the soil analysis and developed the recommendations for soil acidity management and fertilizer application.

Before disseminating the soil analysis results and recommendations to the farmers, Cropnuts trained 53 agricultural officers in each of the study counties. “The purpose of the training was to expose the officers to the technical aspects of the soil analysis and interpretation of soil test results the basis on which the recommendations were made,” says Dr.  Olwande. “The training covered areas like Understanding soil analysis report; Interpretation of soil analysis data; Role of various nutrients in maize production; Negative effects of soil acidity on nutrients availability to maize plants among others,”

The soil test results and recommendations for acidity management and fertilizer application were distributed to the individual farmers whose soils were sampled and the farmers whose soils were not sampled but are part of the research. The researchers and Aagricultural Officers held in-person meetings with farmers across the 120 target villages and delivered and explained to them the results of the soil tests and recommendations. “This feedback session with the farmers was critical. While a few  farmers had had their soil samples taken by some organizations for testing before, none of them had ever received soil test results,” says Dr. Olwande

Emerging evidence from this study points to the importance of soil testing and its critical role in improving farm productivity among smallholder farmers. Importantly, based on these findings, the researchers provided a set of farm-specific and ward-level recommendations for maize production. First, they recommended application of calcitic and dolomitic lime to correct soil acidity. Majority of the farmers have heard about agricultural lime and acknowledge that lime is available in local agrodealer shops, but few of them have applied lime to their farms despite the fact that liming is required on majority of the farms.  

Secondly, the researchers also recommended the types of fertilizers to apply and the application rate, as well as application of organic matter (manure and/or compost). The fertilizers recommended to the farmers were locally available in the agrodealer shops, while some were being sold by county governments under their respective subsidy programmes.

“Through this project, ICED is strengthening locally-led research solutions to local development challenges experienced by critical sectors like agriculture.  We hope that insights from this project will be instrumental in shaping adoption of soil-testing and application of appropriate soil management practices by smallholders for improved yields,” says Dr. David Ameyaw, ICED’s CEO.