Tropentag, September 16 - 18, 2026, Göttingen "Towards multi-functional agro-ecosystems promoting climate-resilient futures"

Potential of selected soil and water conservation practices to reduce greenhouse gas intensity in sub-humid agro-ecozones of Kenya

¹Intern. Centre of Insect Physiology and Ecology (ICIPE), Kenya
²Cortile Scientific Limited, Kenya
³Res. Inst. of Organic Agriculture (FiBL), Dept. of Intern. Coop., Switzerland
⁴University of Embu, Dept. of Water and Agricultural Resource Management, Kenya
⁵International Centre of Insect Physiology and Ecology (icipe), Kenya
⁶OCP Nutricrops, Morocco

Abstract

Food insecurity and global warming are major challenges for agricultural production. Soil and water conservation practices (SWCPs) can improve crop yields through hydrothermal regulation and are widely applied as a common practice among smallholder farmers. However, their impacts on net global warming potential (GWP) and greenhouse gas intensity (GHGI) are not well understood. We implemented mulching and tied ridges with the following treatments: mulch‑conventional (MCONV), mulch‑integrated (MINT), mulch‑organic (MORG), tied ridge‑conventional (TRCONV), tied ridge‑integrated (TRINT), tied ridge‑organic (TRORG), and the control in randomised incomplete block design to evaluate the effects of SWCPs on GWP and GHGI. We employed static, vented chamber techniques for greenhouse gas sampling. We used mixed linear model fitted with lmer function during data analysis. Net GWP (p < 0.001) and GHGI (p < 0.001) significantly varied by treatment. We observed high CH₄ uptake under TRORG (-247%, p=0.02) compared to the control. There were significantly higher CO₂ and N₂O emissions under MORG and TRORG compared to control. We observed increased CO₂ emissions by +54% and +65%, and N₂O emissions by +217% and +238% under MORG and TRORG respectively compared to control (p < 0.05). Compared to the control, net GWP was higher under MINT (+118%) and TRINT (+115%), while it was significantly lower under TRORG (−32%). We observed high GHGI sinks under TRORG (−86%), and MRORG (−74%). Although CO₂ and N₂O emissions increased under organic-based treatments, enhanced CH₄ uptake and yield effects resulted in reduced net GWP and strong GHGI sinks, particularly under TRORG. These findings suggest that integrating tied ridges with organic inputs increases GHGI sinks without compromising crop yields.

Keywords: Climate- smart agriculture, greenhouse gas intensity, greenhouse gas mitigation, sub-Saharan Africa

Contact Address: Esphorn Kibet, Intern. Centre of Insect Physiology and Ecology (ICIPE), Nairobi, Kenya, e-mail: esphornkibetgmail.com