The role of climate, vegetation, and soil factors on carbon fluxes in Chinese drylands

Zhaogang Liu; Zhi Chen; Guirui Yu; Weikang Zhang; Tianyou Zhang; Lang Han

doi:10.3389/fpls.2023.1060066

The role of climate, vegetation, and soil factors on carbon fluxes in Chinese drylands

Front Plant Sci. 2023 Feb 9:14:1060066. doi: 10.3389/fpls.2023.1060066. eCollection 2023.

Authors

Zhaogang Liu^{1

2}, Zhi Chen^{1

2

3}, Guirui Yu^{1

2

3}, Weikang Zhang^{1

2}, Tianyou Zhang⁴, Lang Han⁵

Affiliations

¹ Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing, China.
² College of Resources and Environment, University of Chinese Academy of Sciences, Beijing, China.
³ Yanshan Earth Critical Zone and Surface Fluxes Research Station, University of Chinese Academy of Sciences, Beijing, China.
⁴ College of Grassland Agriculture, Northwest A&F University, Yangling, China.
⁵ Institute of Surface-Earth System Science, School of Earth System Science, Tianjin University, Tianjin, China.

Abstract

Drylands dominate the trend and variability of the land carbon (C) sink. A better understanding of the implications of climate-induced changes in the drylands for C sink-source dynamics is urgently needed. The effect of climate on ecosystem C fluxes (gross primary productivity (GPP), ecosystem respiration (ER), and net ecosystem productivity (NEP)) in drylands has been extensively explored, but the roles of other concurrently changing factors, such as vegetation conditions and nutrient availability, remain unclear. We used eddy-covariance C-flux measurements from 45 ecosystems with concurrent information on climate (mean annual temperature (MAT) and mean annual precipitation (MAP)), soil (soil moisture (SM) and soil total nitrogen content (soil N)), and vegetation (leaf area index (LAI) and leaf nitrogen content (LNC)) factors to assess their roles in C fluxes. The results showed that the drylands in China were weak C sinks. GPP and ER were positively correlated with MAP, while they were negatively correlated with MAT. NEP first decreased and then increased with increasing MAT and MAP, and 6.6 °C and 207 mm were the boundaries for the NEP response to MAT and MAP, respectively. SM, soil N, LAI, and MAP were the main factors affecting GPP and ER. However, SM and LNC had the most important influence on NEP. Compared with climate and vegetation factors, soil factors (SM and soil N) had a greater impact on C fluxes in the drylands. Climate factors mainly affected C fluxes by regulating vegetation and soil factors. To accurately estimate the global C balance and predict the response of ecosystems to environmental change, it is necessary to fully consider the discrepant effects of climate, vegetation, and soil factors on C fluxes, as well as the cascade relationships between different factors.

Keywords: carbon flux; climate change; dryland; grassland; soil; vegetation.

Grants and funding

This study was supported by the National Natural Science Foundation of China (41991234, 42141005, 32222052), Young Talents Project of Institute of Geographic Sciences and Natural Resources Research (2021RC004), Youth Innovation Promotion Association of Chinese Academy of Sciences (2022050), and the Science and Technology Basic Investigation Program of China (2019FY101302).