Soil carbon dioxide (CO₂–C) fluxes measured from automated static closed chambers in maize and potato plots in Uasin Gishu County, Kenya. CO₂ fluxes represent total soil respiration (heterotrophic and autotrophic combined) and were recorded simultaneously alongside N₂O and CH₄ using a cavity ring-down spectrometer (Picarro G2308, Picarro Inc., USA) during 45-minute sequential chamber closures at sub-daily resolution. Data span March 2024 to March 2025 at the University of Eldoret, Uasin Gishu County, Kenya (0°34′45″N, 35°18′22″E; 2,213 m a.s.l.) on Ferralsol soils. Four nitrogen fertilisation rates were applied to maize and potato in a randomised complete block design with three replicates: maize at 50 kg N ha⁻¹ , maize at 100 kg N ha⁻¹, potato at 50 kg N ha⁻¹ , and potato at 100 kg N ha⁻¹. Data were collected to characterise soil respiration dynamics across crop types and fertilisation treatments, to provide CO₂ as a co-regulator of the soil carbon balance alongside N₂O and CH₄ fluxes, and to use CO₂ regression linearity as a quality control indicator for all chamber-based flux measurements. Fluxes are reported in mg CO₂–C m⁻² h⁻¹. This dataset is part of a multi-variable collection archived at PANGAEA.