Environmental drivers of soil organic carbon in the Australian rangelands
Year: 2025
Type: article
Abstract: Soil organic carbon (SOC) is vital for maintaining healthy ecosystems and providing various benefits beyond climate change mitigation. These benefits include supporting biodiversity and improving nutrient cycling, fertility and soil structure. This study aims to investigate the environmental drivers of SOC content across the vast Australian rangelands at different spatial scales. We describe the state of SOC as a function of a large set of soil and environmental variables, representing factors that represent soil mineralogy, climate, vegetation, topography, and soil microbial diversity. We used a quantitative hierarchical framework over three distinct climate zones to gain a systematic understanding of the controls of SOC variability at a macro, regional and local scale. Over the macro-scale of the rangelands, we find that climate is the dominant control of SOC in the Australian rangelands and influences SOC both directly and indirectly through its effects on vegetation growth. At the regional scale, the distribution of SOC is largely determined by regional controls such as soil texture and mineralogy and microbial diversity, vegetation cover and type and plant species richness, and local terrain features. At a local transect scale, SOC variability is affected by vegetation type and biomass, terrain attributes (terrain wetness index, plan curvature and erosion), soil mineralogy and microbial diversity. At these local scales, where plant carbon inputs are not limited by climate, vegetation type is the most significant driver. Where plant carbon inputs are limited by climate, SOC is controlled by vegetation biomass and type and soil mineralogy. Vegetation with shallow roots and limited soil development, contributes minimal carbon to the subsoil, whereas deep-rooted vegetation, less limited by climate, sequesters significant carbon. Our results provide insights into the drivers of SOC content in Australian rangelands and could serve to develop strategies for long-term SOC sequestration and restoration.
Source: CATENA
Institution: Curtin University
Language: English
Subfield: Soil Science
Domain: Life Sciences
SDGs: Climate action, Life on land
Open Access status: hybrid
Estimated APC paid: $3,680
OpenAlex ID: W4409282984