Distribution Patterns and Influencing Factors Controlling Soil Carbon in the Heihe River Source Basin, Northeast Qinghai–Tibet Plateau

Meiliang Zhao (), Guangchao Cao (), Qinglin Zhao, Yonggui Ma, Fuling Zhang, Hongda Li, Qixin He and Xunxun Qiu
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Meiliang Zhao: Key Laboratory of Environmental Surface Processes and Ecological Conservation, Ministry of Education, Qinghai Normal University, Xining 810008, China
Guangchao Cao: Key Laboratory of Environmental Surface Processes and Ecological Conservation, Ministry of Education, Qinghai Normal University, Xining 810008, China
Qinglin Zhao: Key Laboratory of Environmental Surface Processes and Ecological Conservation, Ministry of Education, Qinghai Normal University, Xining 810008, China
Yonggui Ma: Qinghai Provincial Government—Beijing Normal University Institute of Plateau Science and Sustainable Development, Xining 810008, China
Fuling Zhang: Provincial Natural Resources Remote Sensing Center of Qinghai Province, Xining 810008, China
Hongda Li: Qinghai General Station of Grassland, Xining 810008, China
Qixin He: Key Laboratory of Environmental Surface Processes and Ecological Conservation, Ministry of Education, Qinghai Normal University, Xining 810008, China
Xunxun Qiu: Key Laboratory of Environmental Surface Processes and Ecological Conservation, Ministry of Education, Qinghai Normal University, Xining 810008, China

Land, 2025, vol. 14, issue 2, 1-16

Abstract: Soil organic carbon (SOC) and soil inorganic carbon (SIC) are key components of soil carbon pools in arid ecosystems, playing a crucial role in regional carbon cycling and climate change mitigation. However, the interactions between these two forms of carbon in arid alpine ecosystems remain underexplored. This study was conducted in the Heihe River Basin (HRB) in the northeastern Qinghai–Tibet Plateau, focusing on the distribution and dynamics of SOC and SIC in deep soil layers. Using data from 329 samples collected from 49 soil profiles extending to the bedrock, combined with path analysis, we explored the inter-relationships between SOC and SIC and quantified the influence of environmental factors. The results showed that (1) SOC exhibited a unimodal distribution with elevation, peaking at 3300–3600 m, while SIC continuously decreased with elevation, with reduction rates ranging from −0.39% to −31.18%; (2) SOC and SIC were significantly positively correlated (r = 0.55, p < 0.01), with SOC decreasing with depth and SIC showing an inflection point at 50 cm depth; (3) SOC was primarily driven by nutrient factors, such as total nitrogen (TN), with a path coefficient of 0.988, while SIC was influenced by abiotic factors, including potential evapotranspiration (PET), with a coefficient of −1.987; (4) SOC density accounted for 81.62% of the total soil carbon pool, playing a dominant role in carbon storage, whereas SIC density exhibited dynamic changes, particularly at depths of 110–150 cm. These findings advance our understanding of deep soil carbon dynamics in arid alpine ecosystems and provide critical data for improving carbon management strategies in similar regions.

Keywords: soil organic carbon; soil inorganic carbon; path analysis; the Qinghai–Tibet Plateau (search for similar items in EconPapers)
JEL-codes: Q15 Q2 Q24 Q28 Q5 R14 R52 (search for similar items in EconPapers)
Date: 2025
References: View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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