Enhancing coffee productivity and disease resilience through ecological farming: evidence from smallholder systems in Kenya

Introduction Climate variability, soil degradation, and increasing pest and disease pressure threaten the sustainability of Arabica coffee production in East Africa. Eco-friendly farming practices-such as no-tillage, organic mulching, composting, and the use of Indigenous Microorganisms (IMOs)-are increasingly promoted as climate-adaptive alternatives to conventional systems, yet empirical evidence of their effectiveness in African smallholder contexts remains limited. In this study, eco-friendly farming is defined as a project-standardized combination of these practices together with field-made microbial inputs. Methods To evaluate its agronomic and plant-health impacts, this study assessed eco-friendly coffee farming among purposively selected smallholder farmers in Embu County, Kenya. From 100 trained farmers, 34 were selected based on early adoption and the availability of complete yield records. A paired-plot design was applied to compare eco-friendly and conventional management within farms, using per-tree yield and the incidence of Coffee Berry Disease (CBD) and Coffee Leaf Rust (CLR) as outcome indicators. Results Eco-friendly management significantly increased coffee yield during the 2024/2025 main harvest, with an average gain of 1.12 kg per tree compared to conventional plots (p < 0.001). Disease suppression was substantial in 2024, with CBD incidence reduced by 89% and CLR by 93%, supported by very large effect sizes (CBD d = 2.24; CLR d = 2.10). Although overall disease pressure declined markedly in 2025, eco-friendly plots maintained lower CBD levels and comparable CLR levels relative to conventional plots. Early adopters exhibited greater yield gains, suggesting cumulative benefits as soil biological processes stabilized. Input costs were comparable between the two systems, indicating that productivity and plant-health improvements were achieved without increasing production expenses. Discussion Because the analysis is based on a single extended production cycle (January 2024-September 2025), further multi-season monitoring is required to evaluate long-term ecological stability and economic sustainability under variable climatic conditions.