5 Conclusion
In this study, we found that SIC stocks increased from 0 to 300 cm after
afforestation in arid semi-arid sandy land, indicating that the
afforestation of sandy land increased the soil carbon sequestration
capacity. 0-300 cm SIC increased continuously (insignificantly) with
stand age, while the difference between MS and other stand age stages of
soil inorganic carbon was significant. Afforestation in semi-arid sandy
areas not only increased SIC storage but also significantly changed the
profile distribution characteristics of SIC. Soil moisture had a
significant effect on SIC in all layers, while pH had a significant
effect on SIC in deep layers. The decreasing rate of inorganic carbon
fixation with increasing stand age implies that the rate of soil
inorganic carbon fixation is not a constant value, and it is necessary
to quantify the temporal pattern of SIC changes to accurately estimate
the dynamics of regional SIC stocks. Our study also highlights the
importance of deep SIC stocks in semi-arid regions in soil carbon sink
estimation.
Funding: This study was supported by the Major Science and
Technology Project in Inner Mongolia Autonomous region of China (No.
Zdzx2018057), the Innovation Cross Team Project of Chinese Academy of
Sciences, CAS (No. JCTD-2019-19), Transformation Projects of Scientific
and Technological Achievements in Inner Mongolia Autonomous region of
China (No. 2021CG0046), and Groundwater environmental evolution in
Minqin Basin under the influence of climate change and human activities
(No. 23JRRA611).
Data availability statement: The original contributions
presented in the study are 404 included in the article/Supplementary
Material. Further inquiries can be directed to the 405 corresponding
author.