Rock weathering controls the potential for soil carbon storage at a continental scale

Summary

This continental-scale modelling study establishes that rock-derived primary minerals create reactive, poorly crystalline minerals during weathering, which bind and store organic carbon in soil. The authors found that poorly crystalline minerals and their correlation with soil organic carbon are concentrated in geographically limited zones where humid climate and abundant primary minerals co-occur to sustain enhanced weathering. The work confirms that rock weathering enhances soil carbon storage capacity, but also reveals that this mechanism's influence is limited across vast areas with low weathering rates.

UK applicability

The UK experiences variable weathering rates depending on geology and climate; temperate, humid regions with high primary mineral abundance may benefit from enhanced soil carbon storage via the weathering mechanism identified here. However, the study's USA-specific model would require UK-localised calibration to predict soil carbon storage potential in British soil types and climates.

Key measures

Primary mineral weathering rates; geographic distribution of poorly crystalline minerals; soil organic carbon abundance and correlation; climate and primary mineral co-occurrence patterns

Outcomes reported

The study modelled the relationship between primary mineral weathering rates and the geographic distribution of poorly crystalline minerals across the USA, then evaluated how rock weathering influences soil organic carbon storage. Results showed that poorly crystalline minerals are most abundant and most strongly correlated with organic carbon in zones where enhanced weathering occurs, with implications for soil carbon storage capacity at continental scales.

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