Improving food security and farmland carbon sequestration in China through enhanced rock weathering: Field evidence and potential assessment in different humid regions
Fuxing Guo, Haowei Sun, Jing Yang, Linsen Zhang, Yan Mu, Yanping Wang, Fuyong Wu
Enhanced rock weathering (ERW) in farmland is an emerging carbon dioxide removal technology with crushed silicate rocks for soil improvement. However, due to climatic variability and field data limitations, uncertainties remain regarding the influence of ERW on food security and soil carbon pools in temperate regions. This study focused to evaluate the crop productivity and carbon sequestration potential of farmland ERW in China by conducting field monitoring in different humid regions and ERW performance model. Additionally, the contribution of climate, soil, and management factors to ERW-mediated yield and carbon sequestration changes was explored using random forest and correlation networks. Field monitoring indicated that farmland ERW significantly improved crop yield in humid region (13.5 ± 5.2 %), along with notable improvements in soil pH and available nutrients. Precipitation (10.4–16.7 %) and soil pH (9.7–16.8 %) had the highest contribution on ERW mediated yield and carbon sequestration changes, but the contribution of management factors (24–26.2 %), especially N input (2.7–7.0 %), should not be disregarded. The model evaluation demonstrated that the carbon sequestration rate of farmland ERW in China can reach 0.28–0.40 Gt yr−1, thereby presenting an opportunity to expand and accelerate the nationally determined contributions of China. The mean sequestration cost of farmland ERW was 633 ± 161 CNY ¥ t-CO2−1, which was an attractive sequestration price considering the positive benefits of rock powder on soil pH and nutrients. Deploying ERW in acidified and mineral nutrient deficient regions was able to serve as an alternative to lime and part chemical fertilizers to improve yield and maximize agricultural sustainability and resource co-benefits. Farmland ERW also has the potential to resource silicate waste to assist traditional, difficult-to-decarbonize industries to reduce carbon emissions. As a result, a comprehensive assessment of existing artificial silicate waste materials could further expand the application of farmland ERW.