Hierarchical drivers shaping the global patterns of soil organic carbon

Recent advancements in observational data and experimental research have significantly enhanced our understanding of the mechanisms governing the magnitude, distribution, and dynamics of soil organic carbon (SOC). However, few studies have systematically explored the hierarchical drivers of SOC. This study addresses this gap by integrating multiple independent datasets—covering productivity, carbon allocation, carbon turnover, and carbon fractions—to construct a comprehensive framework for the hierarchical drivers shaping global SOC patterns. Using this framework, we examine the impact pathways and contributions of primary drivers. Our findings show that climate, as the fundamental primary driver, mainly influences SOC through carbon input pathways, while soil properties, as a secondary driver, predominantly affect SOC via carbon output pathways. Further analysis reveals that carbon input plays a key role in shaping topsoil SOC distribution, while carbon output is more influential in re..., , , # Hierarchical drivers shaping the global patterns of soil organic carbon

[https://doi.org/10.5061/dryad.ksn02v7g8](https://doi.org/10.5061/dryad.ksn02v7g8)

## Description of the data and file structure

The NPP data (data_NPP.xlsx) were mainly sourced from a peer-reviewed meta-analysis (Xiao et al., 2023), which synthesized NPP data from published papers and the ORNL DAAC ([https://daac.ornl.gov/cgi-bin/dataset_lister.pl?p=13](https://daac.ornl.gov/cgi-bin/dataset_lister.pl?p=13)). Besides, we filtered the NPP database for grassland (Sun, Chang, & Fang, 2023) using following criteria: (1) Sites must include measurements of NPP, BNPP, and ANPP, enabling the calculation of the fraction of net primary production (NPP) allocated belowground (fBNPP); (2) Sites should not have been subject to experimental treatments; and (3) BNPP measurements were obtained using \"soil core\" or \"ingrowth core\" methods, as both approaches yielded comparable fBNPP values and provided the largest sample size. ...,