Storage of Soil Organic Carbon and Its Spatial Variability in an Agro-Pastoral Ecotone of Northern China

Yanjiang Zhang, Qing Zhen, Pengfei Li, Yongxing Cui, Junwei Xin, Yuan Yuan, Zhuhua Wu and Xingchang Zhang
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Yanjiang Zhang: College of Nature Resources and Environment, Northwest A&F University, Yangling 712100, China
Qing Zhen: College of Nature Resources and Environment, Northwest A&F University, Yangling 712100, China
Pengfei Li: Upper and Middle Yellow River Bureau, Yellow River Conservancy Commission of the Ministry of Water Resources, Xi’an 710021, China
Yongxing Cui: Institute of Soil and Water Conservation, Chinese Academy of Sciences and Ministry of Water Resources, Yangling 712100, China
Junwei Xin: College of Nature Resources and Environment, Northwest A&F University, Yangling 712100, China
Yuan Yuan: College of Nature Resources and Environment, Northwest A&F University, Yangling 712100, China
Zhuhua Wu: College of Nature Resources and Environment, Northwest A&F University, Yangling 712100, China
Xingchang Zhang: College of Nature Resources and Environment, Northwest A&F University, Yangling 712100, China

Sustainability, 2020, vol. 12, issue 6, 1-13

Abstract: Spatial distribution of soil organic carbon (SOC) is important for the development of ecosystem carbon cycle models and assessment of soil quality. In this study, a total of 732 soil samples from 122 soil profiles (0–10, 10–20, 20–40, 40–60, 60–80, and 80–100 cm) were collected by a combination of fixed-point sampling and route surveys in an agro-pastoral ecotone of northern China and the spatial variation of the SOC in the samples was analyzed through classical statistical and geostatistical approaches. The results showed that the SOC contents decreased from 4.31 g/kg in the 0–10 cm to 1.57 g/kg in the 80–100 cm soil layer. The spatial heterogeneity of the SOC exhibited moderate and strong dependence for all the soil layers owing to random and structural factors including soil texture, topography, and human activities. The spatial distributions of the SOC increased gradually from northeast to southwest in the 0–40 cm soil layers, but there was no general trend in deep soil layers and different interpolation methods resulted in the inconsistent spatial distribution of SOC. The storage of SOC was expected to be 25 Tg in the 0–100 cm soil depths for the whole area of 7692 km 2 . The SOC stocks estimated by two interpolation approaches were very close (25.65 vs. 25.86 Tg), but the inverse distance weighting (IDW) interpolation generated a more detailed map of SOC and with higher determination coefficient (R 2 ); therefore, the IDW was recognized as an appropriate method to investigate the spatial variability of SOC in this region.

Keywords: spatial heterogeneity; soil organic carbon content; agro-pastoral ecotone; geostatistical analysis (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2020
References: View references in EconPapers View complete reference list from CitEc
Citations: View citations in EconPapers (1)

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