Carbon dioxide removal through the enhanced weathering of basalt in acidic soils under sugarcane

Supervisor

Enhanced weathering (EW) offers a potential negative emissions technology. Modelling suggests significant carbon dioxide removal (CDR) but requires field verification. This study quantifies CDR through EW of basalt and examined the influence of soil pH. The experiment received five annual basalt applications of 50t/ha since 2018 and 2.5t/ha lime in 2022. Drainage flux meters were installed to capture leachate during the 2022/23 wet season, and bicarbonate was measured, indicating CDR. Cumulative bicarbonate was not significantly influenced by basalt or lime. CDR was negligible compared to potential bicarbonate generation, with strong acids found to limit in-field CDR. Nitric and organic acids found aligned with fertiliser application, microbial activity and plant root exudation. Acidic soils may require amelioration for CDR through EW, although the neutralising effect of basalt application may reduce CO2 evasion.

01 Feb 2025 - 01 Feb 2028

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