Grasslands and soil carbon: What can livestock management practices teach us? A global map of scientific knowledge

Grasslands represent a vast resource, covering >40% of the Earth’s land surface, supporting biodiversity, reducing erosion risks, and storing carbon (C) in soils. Yet they are increasingly threatened by land-use intensification, land degradation, and climate change. In response to these multiple pressures, numerous scientific studies have examined how grasslands function and what their environmental and socio-economic roles are across diverse climatic, soil, and management contexts. To provide an integrated overview of this complexity, we developed the first systematic global map that synthesises scientific knowledge from field experiments investigating how grassland management practices influence soil C in livestock systems¹.

For this global synthesis, 31215 scientific studies in five languages were screened from several major databases (e.g., Web of Science, Scopus, CABI). Each publication was assessed using strict inclusion and exclusion criteria to ensure the reliability of the data retained¹. We extracted and mapped information on management practices, from grazing and fertilisation to irrigation, plant composition, and biochar addition, as well as on soil C measurement types (e.g., concentration, stock, sequestration rate), pedoclimatic contexts, and experimental approaches (e.g., study duration, randomisation).

Between 1991 and 2024, the number of studies investigating the effects of grassland management on soil C increased exponentially. Most research has been conducted in temperate, high or upper-middle-income regions, particularly in China, the United States, and parts of Europe, while major gaps persist in Africa and tropical regions. Research has primarily focused on grazing (presence/absence, stocking density), fertilisation, and plant community management. More than half of the studies relied on established agricultural plots, using a space-for-time substitution approach (i.e. comparing long-term management sites to infer temporal trends).

This global map highlights both areas with relevant knowledge and knowledge gaps: key practices such as silvopastoral systems or grazing duration remain understudied. Gaining a deeper understanding of the effects of management practices on C sequestration and soil C fractions, particularly at depths beyond the top 30 cm, is essential to refine models and enhance the accuracy of global C stock estimates.

The compiled dataset represents a valuable resource for the scientific community. It can support future meta-analyses or the identification of knowledge gaps that merit further investigation.

 

Acknowledgements
This research was developed within the framework of the European Joint Program for SOIL, "Managing and Mapping Agricultural Soils for Enhancing Soil Functions and Services" (EJP SOIL), project CARBOGRASS, funded by the European Union Horizon 2020 research and innovation programme (Grant Agreement No. 862695).

 Reference

1. Rousset, C., Segura, C., Gilgen, A. et al. (2024). What evidence exists relating the impact of different grassland management practices to soil carbon in livestock systems? A systematic map protocol. Environmental Evidence, 13, 22. https://doi.org/10.1186/s13750-024-00345-2