Effects of establishing cultivated grassland on soil organic carbon fractions in a degraded alpine meadow on the Tibetan Plateau

PeerJ

article

Xiang Liu¹  Xiaotao Huang²  Wenping Qin¹  Xiaoan Li⁴  Zhiwen Ma⁴  Hongxiao Shi⁵  Lanhai Li⁷  Changzhong Li⁴ 

[1] State Key Laboratory of Plateau Ecology and Agriculture, Qinghai University;Key Laboratory of Restoration Ecology for Cold Regions Laboratory in Qinghai, Northwest Institute of Plateau Biology, Chinese Academy of Sciences;Key Laboratory of Adaptation and Evolution of Plateau Biota, Chinese Academy of Sciences;College of Eco-Environmental Engineering, Qinghai University;Institute of Grassland Research, Chinese Academy of Agricultural Sciences;Qinghai Academy of Animal and Veterinary Sciences, Qinghai University;State Key Laboratory of Desert and Oasis Ecology, Xinjiang Institute of Ecology and Geography, Chinese Academy of Sciences;CAS Research Centre for Ecology and Environment of Central Asia

关键词: Soil organic carbon fractions;    Biochemical stability;    Grassland restoration;    Alpine region;    C:N ratio;   

DOI  :  10.7717/peerj.14012

学科分类：社会科学、人文和艺术（综合）

来源: Inra

【 摘 要 】

BackgroundThe degradation of alpine meadows has induced substantial losses of soil organic carbon (SOC) on the Tibetan Plateau. A commonly-used method for rehabilitating degraded alpine meadows in this region is establishing cultivated grasslands through sowing seed mixtures, but its impact on the biochemical stability of SOC has remained inadequately explored.MethodsIn this study, a total of 20 composited 0-20 cm soil samples were collected from a heavily degraded alpine meadow (DM) and three adjacent cultivated grasslands established for 3 years (CG3), 12 years (CG12), and 17 years (CG17) on the eastern Tibetan Plateau, and the SOC pool was separated into labile C pool I (LOC I), labile C pool II (LOC II), and recalcitrant C pool (ROC) in order to investigate changes in contents of SOC fractions that have different biochemical stabilities after the establishment of cultivated grassland.ResultsAlthough the establishment of cultivated grasslands led to increases in soil total organic C content, the increase was only significant in samples with 17 years of cultivation. We found that the contents of the three SOC fractions were higher at CG3 and CG12 compared with those in the DM, and the differences were only significant for soil LOC II. By comparison, 17 years of cultivation led to significant increases in all of the SOC fraction contents. The results implied that different cultivation years had distinct impacts on SOC fractions in cultivated grasslands, and longer cultivation years contributed to accumulated soil ROC. The recalcitrance index of SOC in the DM was higher than that at CG3 and CG12, but lower than that at CG17. This was possibly due to the generally low litter quality of cultivated grasslands, which led to a slow release of complex compounds to soils. Moreover, it was observed that soil C:N ratio was a potential indicator of SOC biochemical stability because of their close correlation.ConclusionsOur findings suggest that the long-term establishment of cultivated grasslands on DM is a promising solution to recovering both the quantity and stability of SOC on the Tibetan Plateau.

【 授权许可】

CC BY