Evaluating indices of soil organic carbon stability. A case study for forest restoration projects near Beijing, China

Zeyu Zhang, Tonggang Zha*, Yang Yu, Xiaoxia Zhang, Pete Smith, Jesús Rodrigo-Comino

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

4 Citations (Scopus)
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Abstract

Afforestation of degraded lands close to mega-urban areas such as Beijing may help to restore some of the original soil carbon stocks and hold the potential for ameliorating the rate of increase in atmospheric CO2. However, the determinants of the stability of different soil carbon pools and the utility of indices of stability remain poorly characterized near these highly anthropogenic areas. In the current study, we compared metrics of soil organic carbon (SOC) stability taking into account different soil types and plantation forest combinations (Quartisamment soil-poplar plantation–QP, Eutrochrepts soil-Chinese pine plantation–ECP, Haplustepts soils-East-Liaoning oak plantation–HEO), in an experimental sub-humid area close to a mega-urban area (Beijing, China). We evaluated the following relative stability indices sequence: respired carbon from incubations (RI) for several incubation days to respire 5% of initial SOC (D), aggregate stability index (ASI), the ratio of SOC to total nitrogen (C: N), water-soluble carbon (WSC), particulate organic carbon (POC) and microbial biomass carbon (MBC). We examined the indices by three repeated measurements on soil samples from four soil layers (0–40 cm) in three soil-forest types in a forest area close to the peri-urban area of Beijing. Our results showed that there are inconsistencies among the six SOC stability indexes. The contribution rates of different indexes to the SOC in three plantations were different, for QP the highest contributor is WSC (54.73%), and for ECP and HEO the highest contributor is RI, contribution rates are 34.85% and 36.382%, respectively. Respired carbon from incubations registered the largest contribution rate to SOC (69.79%), and the correlation between RI and soil physical and chemical properties was the highest. We conclude that a combination of indices and knowledge of soil and vegetation types are needed for assessing SOC stability in restoration and reforestation projects close to mega-urban areas.

Original languageEnglish
Article number109222
Number of pages9
JournalEcological Indicators
Volume142
DOIs
Publication statusPublished - Sept 2022

Bibliographical note

Funding Information:
This study was funded by Forestry scientific and technological achievements Popularization Project of State Forestry Administration ([2019] 3) and China State Construction Technology R&D Program Funding (CSECE-2020-Z-5). The authors gratefully acknowledge the Jiufeng National Forest Park (Haidian District, Beijing) and Daxing Forestry Centre (Daxing district, Beijing) for giving access to conduct fieldwork on their experimental sites.

Publisher Copyright:
© 2022 The Author(s)

Data Availability Statement

Data will be made available on request.

Keywords

  • Forest
  • Mega-cities
  • Relative stability indices
  • Soil organic carbon stability
  • Soil types

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