Is the Change of Soil Carbon Capacity Persistence Rising or Remain Stable With Maturity of Vegetation Restoration?

Qian Liu,Peipei Wang,Zhijing Xue,Zhengchao Zhou,Shaoshan An,Jun'E Liu

doi:10.3389/fsoil.2021.663910

Abstract

Emerging consensus is that land-use change resulting through the “Grain for Green” project has had a significant impacted on soil organic carbon (SOC), thereby probably enhancing the carbon sequestration capacity of terrestrial ecosystems. However, it remains largely unknown whether a watershed acts as a source or sink of soil carbon during the later period of ecological restoration. This study comprehensively investigated the changes of SOC stock in 2005, 2010, and 2017 along different land-use types. It was aimed to evaluate the dynamics to SOC storage capacity over different vegetation restoration maturity in the Shanghuang Watershed, China. The results showed that restoration increased the accumulation of organic carbon pools in the early stage. Significant increases in SOC stock were observed in shrubland and grassland in comparison to that in other land uses, and these two land-use types represented the optimal combination for ecological restoration in the basin. The SOC stock did not increase indefinitely during the long-term vegetation restoration process, but rather first increased rapidly with vegetation planting and reached a peak, following which it declined slightly. Therefore, pure vegetation restoration cannot maintain a permanent soil carbon sink, some measures to maintain the stability of carbon and to prolong soil C persistence are essential to take.

Highlights

The soil carbon pool accounts for a large proportion of the total global carbon pool, and is equivalent to more than twice the terrestrial vegetation carbon pool [1, 2], and three times the size of the atmospheric carbon pool [3, 4]
The processes of soil organic carbon sequestration and decomposition are regulated by several biological factors, such as land use conversion, as well as non-biological factors [6]
GRAPHICAL ABSTRACT | This study comprehensively investigated the dynamics to soil organic carbon (SOC) storage capacity over different vegetation restoration maturity in the Shanghuang Watershed, China

Summary

INTRODUCTION

The soil carbon pool accounts for a large proportion of the total global carbon pool, and is equivalent to more than twice the terrestrial vegetation carbon pool [1, 2], and three times the size of the atmospheric carbon pool [3, 4]. With consideration of previous research results, the current study had the following objectives: [1] identify the response of the soil organic carbon stock to land-use conversion and the optimal combination of land use for C storage; [2] determine whether the increase in SOC storage with increasing maturity of vegetation restoration results in a peak, and if so, whether SOC storage subsequently stabilizes or gradually declines. To test these hypotheses, the current study investigated the status of soil C under different land-use types from 2005 to 2017. The results of the present study can provide information for determining whether soil carbon storage can continue to increase and can give an indication of the sustainability of the “Grain to Green” project during the later stages ofvegetation restoration in small watersheds on the Loess Plateau

MATERIALS AND METHODS

RESULT

DISCUSSION

CONCLUSIONS

Findings

DATA AVAILABILITY STATEMENT