Abstract

Enhanced weathering (EW) represents a promising carbon dioxide removal (CDR) technology that accelerates natural silicate weathering processes to sequester atmospheric CO₂. This field-scale trial evaluated the effectiveness of basalt and olivine amendments in rice-wheat cropping systems across three sites in northern India. Treatments included basalt (5 t ha⁻¹), olivine (5 t ha⁻¹), and control plots over two complete cropping cycles. CO₂ removal rates were quantified through alkalinity measurements, soil carbon analysis, and atmospheric flux monitoring. Results demonstrated significant CO₂ sequestration with basalt amendment achieving 3.2±0.4 t CO₂ ha⁻¹ yr⁻¹ and olivine achieving 2.8±0.3 t CO₂ ha⁻¹ yr⁻¹ compared to control plots [1, 2]. Soil pH increased from 6.8 to 7.4 in basalt plots and 6.8 to 7.2 in olivine plots, improving nutrient availability [3]. Rice yields increased by 12% and wheat yields by 8% with basalt treatment due to enhanced silicon availability and improved soil chemistry [4, 5]. Water quality monitoring showed no adverse effects on groundwater or surface water alkalinity levels [6]. Economic analysis revealed net costs of $180-220 per tonne CO₂ removed, including transportation and application expenses [7]. These findings demonstrate that enhanced weathering in agricultural systems can provide substantial CDR while delivering co-benefits for crop productivity and soil health.