The lower labile carbon of surface soils in Chinese semiarid areas

ABSTRACT

Hot water extractable organic carbon (HWOC), the labile carbon component, is often used to indicate soil organic carbon (SOC) dynamics. Nevertheless, few studies have been carried out in arid climate areas which affects our full understanding of HWOC. Here, we investigated the change in HWOC in the topsoil of different ecosystems in the southern part of the Loess Plateau in the semiarid region of China and compared it with that in other regions. The HWOC concentrations of the study area (0-10 cm) were 0.27 ± 0.12 g C kg⁻¹ and 0.19 ± 0.04 g C kg⁻¹ in the natural and agricultural systems respectively, and the HWOC proportions were 1.38 ± 0.38% and 2.18 ± 0.22%. The HWOC concentration and proportion in the study area were much lower than the reported data in other areas, which may be affected by drought conditions. Irrigation could weaken the difference in HWOC between agricultural systems in different regions. Since HWOC is easily lost due to the impact of the arid climate, the soil carbon balance and carbon sequestration in arid and semiarid areas are relatively unstable, indicating that soil management should be improved in combination with water management.

KEYWORDS:

• Agricultural system
• arid area
• characterisation of SOC dynamics
• hot water extractable organic carbon
• Loess Plateau
• natural system
• soil management

Acknowledgments

This work was supported by National Natural Science Foundation of China (42173019). Key laboratory of Aerosol Chemistry and Physics, Chinese Academy of Sciences provides soil sample testing services. Acknowledgement for the data support from ‘Soil SubCenter, National Earth System Science Data Center, National Science & Technology Infrastructure of China. (http://soil.geodata.cn)’.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Research Data

Data of soil SOC and HWC in southern Chinese Loess Plateau associated with this article can be accessed at https://data.mendeley.com/datasets/t9vzjvdvn3.

Additional information

Funding

This work was supported by National Natural Science Foundation of China [grant no 42173019].

Notes on contributors

Fan Zhang

All authors participated in data collation. Z.F. developed aims, research questions extracted data and undertook most of the analyses, supported by W.Z. Z.F. drafted the manuscript, all authors contributed to revisions and gave final approval for publication.

Jiamin Qi

All authors participated in data collation. Z.F. developed aims, research questions extracted data and undertook most of the analyses, supported by W.Z. Z.F. drafted the manuscript, all authors contributed to revisions and gave final approval for publication.

Congwen Gui

All authors participated in data collation. Z.F. developed aims, research questions extracted data and undertook most of the analyses, supported by W.Z. Z.F. drafted the manuscript, all authors contributed to revisions and gave final approval for publication.

Yilin Zhang

All authors participated in data collation. Z.F. developed aims, research questions extracted data and undertook most of the analyses, supported by W.Z. Z.F. drafted the manuscript, all authors contributed to revisions and gave final approval for publication.

Zheng Wang

All authors participated in data collation. Z.F. developed aims, research questions extracted data and undertook most of the analyses, supported by W.Z. Z.F. drafted the manuscript, all authors contributed to revisions and gave final approval for publication.