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• Soil tillage and irrigation system affected soil CO 2 emissions. • A threshold value at 60 % WFPS was found for soil CO 2 fluxes under flood irrigation. • No-tillage systems reduced cumulative CO 2 emissions by 30 %. • Sprinkler irrigation increased cumulative CO 2 emissions and total aboveground biomass. • Soil acted as a sink of CH 4 throughout the measurement period. Irrigation as well as soil tillage management are considered two possible strategies to reduce carbon dioxide (CO 2) and methane (CH 4) emissions from the soil in Mediterranean agroecosystems. The objective of this work was to assess the impact of the irrigation system (i.e. flood, F; and sprinkler, S) and the soil tillage system (i.e. conventional tillage, CT; no-tillage maintaining the maize stover, NTr; and no-tillage removing the maize stover, NT) on CO 2 and CH 4 emissions from the soil during three growing seasons (2015, 2016 and 2017) and two fallow periods between growing seasons (15–16 fallow and 16–17 fallow) in a maize (Zea mays L.) monoculture system. Soil temperature and water-filled pore space (WFPS) had a great influence on daily soil CO 2 fluxes but not on daily soil CH 4 fluxes. In all tillage-irrigation treatments, daily soil CO 2 fluxes showed an increase with soil temperature, being this increment greater when soil temperature was above 15 °C in coincidence with the maize plant growth. In contrast, soil WFPS differently affected daily soil CO 2 fluxes depending on the irrigation system. Under S irrigation, daily soil CO 2 fluxes increased with soil WFPS, whereas under F irrigation a threshold value of 60% WFPS was found, with a positive or negative effect on CO 2 fluxes for values below or above this threshold value, respectively. Over the three maize growing seasons, CT-S presented the greatest cumulative soil CO 2 emissions with a seasonal average value of 3.28 Mg CO 2 -C ha−1. In contrast, for the same period, NTr-S cumulative soil CO 2 emissions were up to 42% lower than the CT-S cumulative soil CO 2 emissions. Cumulative CH 4 emissions were only affected by soil tillage during the 16–17 fallow period, resulting both NTr and NT in greater net CH 4 uptake compared with CT. This work highlights the importance of irrigation and soil tillage systems as key agricultural practices to minimize soil CO 2 and CH 4 emissions under Mediterranean conditions. [ABSTRACT FROM AUTHOR]