Chemical composition of soil organic carbon and aggregate stability along an elevation gradient in Helan Mountains, northwest China

Mengyao Wu; Danbo Pang; Lin Chen; Xuebin Li; Lizhen Liu; Bo Liu; Jingyao Li; Jifei Wang; Longlong Ma

Ecological Indicators (Nov 2021)

Chemical composition of soil organic carbon and aggregate stability along an elevation gradient in Helan Mountains, northwest China

Mengyao Wu,
Danbo Pang,
Lin Chen,
Xuebin Li,
Lizhen Liu,
Bo Liu,
Jingyao Li,
Jifei Wang,
Longlong Ma

Affiliations

Mengyao Wu: Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China; Ministry of Education Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China; College of Agriculture, Ningxia University, Yinchuan, Ningxia 750021, China
Danbo Pang: Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China; Ministry of Education Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China
Lin Chen: Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China; Ministry of Education Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China; Corresponding authors at: Institute: Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China, Ningxia University, No.489 Helanshan West Road, Xixia District, Yinchuan 750021, Ningxia Hui Autonomous Region, China.
Xuebin Li: Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China; Ministry of Education Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China; Corresponding authors at: Institute: Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China, Ningxia University, No.489 Helanshan West Road, Xixia District, Yinchuan 750021, Ningxia Hui Autonomous Region, China.
Lizhen Liu: Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China; Ministry of Education Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China
Bo Liu: Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China; Ministry of Education Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China
Jingyao Li: Administration of Ningxia Helan Mountains National Nature Reserve, Yinchuan, Ningxia, 750021, China
Jifei Wang: Ningxia Helan Mountains Forest Ecosystem Positioning Observation and Research Station, Yinchuan, Ningxia 750021, China
Longlong Ma: Breeding Base for State Key Laboratory of Land Degradation and Ecological Restoration in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China; Ministry of Education Key Laboratory for Restoration and Reconstruction of Degraded Ecosystem in Northwest China, Ningxia University, Yinchuan, Ningxia 750021, China

Journal volume & issue: Vol. 131
p. 108228

Abstract

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Exploring the composition of soil organic carbon (SOC) and aggregate stability over a range of elevations is essential to evaluate the stability of SOC and the conversion of carbon source or sink of mountain ecosystems. However, information of those changes in mountain ecosystems in arid and semi-arid regions is still scarce to date. In this study, we estimated the response of SOC stability along elevation gradient (1,380–2,438 m) by combining physical protection of aggregates with chemical protection of SOC using a redundancy analysis method in the Helan Mountains, northwest China. Results showed that the dominated aggregates of Helan Mountains changed from microaggregates to macroaggregates with increasing elevation, and the mean weight diameter (MWD) in mid and high elevations (2,139–2,248 m) was significantly higher than that in low elevations (1,380–1,650 m). Solid-state 13C NMR spectra showed that O-alkyl C was the main chemical composition of SOC in the different elevations. Regression analysis indicated that with the increase of elevation, the proportion of aromatic C and aromaticity gradually increased, peaked at the mid elevation and subsequently decreased. These findings indicated that the soil structure and chemical composition of SOC are more stable in the mid elevation. Macroaggregates were positively correlated with O-alkyl C and aromatic C, while silt and clay were positively correlated with alkyl C, indicative of a lower decomposition rate of macroaggregates. The RDA analysis confirmed that aggregate stability were significant associated with SOC content and chemical composition such as O-alkyl C, indicating that the soil labile carbon pool was most related to affect aggregate stability. Our findings suggest that the Helan Mountains had a better soil structure and a more stable SOC chemical composition at mid elevation ranges. The soil structure at low elevations is sensitive to environment change; therefore, a reduction in anthropogenic disturbance is suggested for improved sustainability of the ecosystem.

Published in Ecological Indicators

ISSN: 1470-160X (Print); 1872-7034 (Online)
Publisher: Elsevier
Country of publisher: United Kingdom
LCC subjects: Science: Biology (General): Ecology
Website: https://www.sciencedirect.com/journal/ecological-indicators

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