# Effects of rock amendment on soil physicochemical properties and organic carbon stabilization

## TL;DR

Adding crushed basalt to soil improves chemical quality without harming physical properties, and soil structure plays a key role in preserving organic carbon.

## Contribution

This study provides new insights into the long-term effects of basalt amendment on soil properties and organic carbon stabilization.

## Key findings

- Basalt amendment improved soil chemical quality without negative effects on physical characteristics.
- Soil structure development increased with basalt and lime treatments compared to control.
- Carbon protection was influenced by soil depth and structural characteristics, not rock amendments.

## Abstract

Enhanced mineral weathering in agricultural settings is an approach for carbon dioxide removal in which crushed silicate rocks are added to soils. However, the effects of long-term application of crushed basalt on soil structure and organic carbon stabilization are still poorly constrained. We investigated a wide range of soil chemical and physical indicators in control, basalt, and lime treatment sites to provide a comprehensive evaluation of soil response to enhanced mineral weathering. The field study showed that soil organic carbon preservation was influenced by soil structure rather than rock additions. Basalt amendment improved overall soil chemical quality, and accumulating basalt from high application rates did not have any negative impact on soil physical characteristics even after six years.

•Basalt grains did not have any negative impact on soil physical characteristics•Soil structural development increased from control < basalt < lime treatments•Organo-mineral associations were unaffected by rock amendment•Soil depth and structural characteristics influenced carbon protection

Basalt grains did not have any negative impact on soil physical characteristics

Soil structural development increased from control < basalt < lime treatments

Organo-mineral associations were unaffected by rock amendment

Soil depth and structural characteristics influenced carbon protection

Geology; soil science; soil chemistry; soil physics