A B S T R A C T
The diffusion of carbon mineralization in vertical profiles is an
important process of CO2 emission. However, due to the
relatively slow and lagging change of subsoil environment compared with
the surface soil, the process of carbon mineralization and diffusion is
often ignored, and the process and mechanism of deep carbon transfer to
the soil-atmosphere interface are still unclear. we studied the vertical
difference of CO2 flux and its driving mechanism inRobinia pseudoacacia plantation of different stand ages. The
results show that: (1) in the 0-200cm layer, the CO2flux shows a double peak seasonal trend. Among them, the total
CO2 flux of Robinia pseudoacacia forest in 10
years was larger. (2) Dynamic evaluation can reduce the uncertainty of
static evaluation, and the contribution of deep CO2 flux
to the soil atmosphere interface is stable, between 21.81-24.42%;
(3)Temperature sensitivity of CO2 flux (expressed as
Q10) significantly increases with soil depth, and the
response of water to CO2 flux is different at different
section. There is a significant correlation between the deep
CO2 flux and soil organic carbon (SOC), but there is a
reverse feedback effect in the shallow profile. (4) T & M & C model is
more conducive to the accurate prediction of deep CO2flux. All in all, this study is of great significance to the study of
the stability of deep soil carbon, the dynamic change of soil carbon
pool and the mechanism of deep carbon diffusion to the surface in the
loess hilly area.
Keywords: CO2flux;Temperature;Moisture;SOC;Deep layer