TWN Info Service on Sustainable Agriculture
10 December 2025
Third World Network
www.twn.my
Dear Friends and Colleagues
Organic maize yields more stable and match yields of conventional systems in Kenya
This study evaluated the effects of organic and conventional farming systems on maize grain yield and temporal yield stability under different external input levels in a long-term experiment (2007–2022) at two sites in Kenya.
Initially, grain yields of conventional systems were higher compared to the organic systems. But the yields of the organic systems gradually increased over time, eventually reaching the levels of conventional systems.
The study demonstrated that organic farming systems have the potential to achieve yields that match or exceed those of conventional farming systems, particularly when given adequate time for soil adaptation and improvement in soil fertility. The low-input farming systems demonstrated greater yield stability, suggesting that they could play an essential role in mitigating risks associated with fluctuating climates and input availability.
To sustainably enhance maize productivity and stability, the researchers recommend focusing on improving soil fertility through sustainable organic practices, including crop rotation, organic inputs, and mulching, all of which can be practically implemented by smallholder farmers in the tropics.
With best wishes,
Third World Network
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MAIZE YIELD STABILITY UNDER ORGANIC AND CONVENTIONAL FARMING SYSTEMS IN SUB-HUMID AGRO-ECOZONES OF CENTRAL KENYA
Milka Kiboi et al.
European Journal of Agronomy
Volume 170, September 2025, 127746
https://doi.org/10.1016/j.eja.2025.127746
https://www.sciencedirect.com/science/article/pii/S1161030125002424?via%3Dihub
Abstract
Maize (Zea mays L.) is the main staple crop and is important to the food security and livelihoods of people globally. We evaluated the effects of organic and conventional farming systems on maize grain yield and temporal yield stability under different external input levels in a long-term experiment (2007–2022) at two sites in Kenya. We implemented four farming systems: organic high (Org-High), conventional high (Conv-High), organic low (Org-Low), and conventional low (Conv-Low) in a randomized complete block design. Growth indicators for maize, height, stem diameter, and grain yield were higher in high input systems, but grain yield stability was not. At the onset of the experiments, grain yields of conventional systems were higher compared to the organic systems, whose yield levels gradually increased over time, reaching the yield levels of conventional systems. With regard to grain yield stability, the site (Chuka) with better soil fertility, the Conv-High system had the least residual variance (0.28 Mg ha−2), followed by Org-Low, Conv-Low, and Org-High showing the highest residual variance (0.67 Mg ha−2). Contrary, in the site (Kandara) with low soil fertility, Org-Low had the lowest residual variance in grain yield (0.16 Mg ha−2), followed by Conv-Low and Org-High, while Conv-High (4.15 Mg ha−2) had the highest residual variance. We observed that applying higher nutrient input levels did not necessarily lead to yield stability. Our findings suggest promoting long-term implementation of organic farming practices, especially in regions with degraded soils, for improved yield and resilience.
Conclusion
Based on the findings of our study, organic farming systems have the potential to achieve yields that match or exceed those of conventional farming systems, particularly in the long term when given adequate time for soil adaptation and improvement in soil fertility. Given the region’s susceptibility to climate variability, it is crucial to consider yield stability alongside average yield performance. Low-input farming systems demonstrated greater yield stability, suggesting that they could play an essential role in mitigating risks associated with fluctuating climates and input availability. To sustainably enhance maize productivity and stability, the study recommends focusing on improving soil fertility through sustainable organic practices, including crop rotation, organic inputs application, and mulching, all of which can be practically implemented by smallholder farmers in Central Kenya or any other regions of similar agro-ecological conditions in the tropics.