Horizon Europe EWRECA Project: Improving silicate erosion in agricultural rice fields: maximizing soil carbon sequestration and crop production while reducing overall greenhouse gas emissions

To limit global warming to 2°C, well below the UN Paris Agreement, model projections indicate that both rapid decarbonization and the deployment of negative emissions technologies (NETs) that ensure stable, long-term carbon (C) sequestration will be required. Among NETs, enhanced weathering (EW) of silicate rocks can remove CO2 from the atmosphere, while potentially generating co-benefits for agriculture (e.g., lower nitrogen losses, higher yields, greater resilience to drought and salinity) and reducing overall greenhouse gas (GHG) emissions from this activity.

Therefore, the application of EW may be of particular interest in rice fields because they emit large amounts of methane (up to 11% of global CH4 emissions); have high water demands and could face drought episodes due to climate change; and are exposed to salt stress in Europe because they are grown in coastal areas. Although some studies have investigated the effects of silicate waste on rice fields, none have combined natural silicate rocks and waste simultaneously.

Furthermore, the quantification of inorganic C sequestration by EW and the potential risks in terms of heavy metal contamination have rarely been assessed. The main objective of EWRECA is to develop an agricultural management practice for rice paddies that (i) minimizes GHG emissions while maximizing (ii) rice production (biomass and quality) and (iii) C sequestration. Furthermore, EWRECA aims to reuse crushed concrete fines, an artificial silicate sourced from construction waste, thus enhancing the circular economy of materials.

To achieve this objective, a mesocosm field experiment will be conducted using different agricultural management treatments. Responses in GHG emissions, plant biomass, and soil microbial communities will be assessed over two growing seasons. Overall, this project will generate valuable scientific results that will be of interest for national, European, and global strategic actions in agricultural systems.