Highlights:
(1) At the layers of 0-200 cm, the CO2 flux exhibits a certain double-peak seasonal and vertical decrease change trend.
(2) The contribute of CO2 flux at deep layers (80-200cm) to the soil-atmosphere interface is stable, lying between 21.81-24.42%.
(3) Temperature sensitivity of CO2 flux (expressed as Q10) significantly increases with soil depth.
(4) Temperature, moisture, and soil organic carbon cooperatively contribute to soil CO2 flux, and the T & M & C model is more conducive to accurate prediction of CO2 flux at deep layers.