Chin J Plant Ecol ›› 2023, Vol. 47 ›› Issue (9): 1245-1255.DOI: 10.17521/cjpe.2023.0028

• Research Articles • Previous Articles     Next Articles

Spatial patterns and determinants of soil organic carbon component contents and decomposition rate in temperate grasslands of Nei Mongol, China

CHEN Ying-Jie1,2, FANG Kai2,3,*(), QIN Shu-Qi2, GUO Yan-Jun1,4, YANG Yuan-He2,5   

  1. 1College of Animal Science and Technology, Southwest University, Chongqing 400715, China
    2State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093, China
    3Research Institute of Forestry, Chinese Academy of Forestry, Beijing 100091, China
    4College of Grassland Science, Qingdao Agricultural University, Qingdao 266109, China
    5University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2023-02-01 Accepted:2023-04-21 Online:2023-09-20 Published:2023-09-28
  • Contact: * FANG Kai(


Aims Grassland is an important component of terrestrial ecosystems around the world and plays an important role in terrestrial carbon cycling. However, large uncertainties still exist in predictions of soil organic carbon (SOC) dynamics in grassland ecosystems using earth system models, partly due to an inadequate understanding of the spatial patterns and drivers of soil carbon components and the rate of decomposition. In this study, we explored the determinants of the contents of total SOC and its components as well as the rate of soil carbon decomposition in the topsoil of temperate grasslands of Nei Mongol.
Methods Soil samples at depths of 0-10 cm were collected during July to August 2015 from field sites on the Nei Mongol Plateau. We measured the contents of total SOC and its partitioning in three soil aggregate size-classes, and the decomposition rate based on laboratory incubation. In addition, we acquired a suite of explanatory factors including climatic, edaphic, vegetation, and mineral variables. Variance partitioning analyses were then used to investigate the relative importance of the four factors in affecting the contents of total SOC, aggregate-classified carbon fractions and soil carbon decomposition rate.
Important findings The contents of total SOC and three carbon fractions displayed an increasing trend from southwest to northeast of the study area, while soil carbon decomposition rate (standardized by SOC) showed a reverse trend. The carbon contents in bulk soil and different aggregate fractions are highest in the meadow steppe, followed by the typical steppe and the desert steppe; whereas soil carbon decomposition rate (standardized by SOC) was highest in the desert steppe, followed by the typical steppe and the meadow steppe. The spatial variations of carbon contents in the three soil aggregate fractions were mainly driven by climatic and mineral factors, with finer soil particles attaching greater relative importance in the effect by the mineral factor. The soil carbon decomposition rate (standardized by SOC) was affected by mineral, edaphic, and climatic factors. These findings highlight the importance of considering the differential influences by minerals in different soil aggregate carbon fractions, particularly the silt- and clay-associated carbon in the Earth system models, so as to improve the accuracy in the prediction of SOC dynamics in grassland ecosystems under changing environment.

Key words: soil organic carbon, carbon fractions, carbon decomposition, mineral, temperate grasslands