Inferring Enhanced Weathering Carbon Dioxide Removal and agronomic impacts from agronomic studies using silicate rock flour: a systematic synthesis

Enhanced Weathering (EW) is increasingly discussed as a scalable carbon dioxide removal (CDR) approach, yet its real-world feasibility remains poorly constrained and is still largely inferred from modeling studies. Here we present results from an international systematic review and database effort that compiles reported CDR estimates alongside geochemical measurements and qualitative meta-data from the rapidly expanding EW literature, as well as from agronomic studies investigating silicate rock flour use as a fertilizer. Focusing on this agronomy-oriented rock flour literature, we leverage reported geochemical observations—including soil and porewater chemistry, changes in soil inorganic carbon stocks, cation exchange capacity and base saturation, and cation release from applied rock powders—to derive novel, observation-constrained estimates of EW-driven CDR. These geochemically derived estimates are integrated with reported CDR values from the broader literature to assess how deployment choices and quantification approaches influence inferred CDR rates. In addition, we systematically analyze reported agronomic responses to silicate rock flour applications, including crop yield and soil pH, to examine how agronomic performance co-varies with geochemical weathering signals and inferred CDR. Across both agronomic responses and CDR estimates, we find evidence for non-linear dose–response behavior with increasing rock application, indicating diminishing marginal benefits at higher rates in many contexts. This pattern suggests that a substantial fraction of agronomic utility and CDR may be achievable at relatively low application rates. The underlying database will be released open access to support transparent synthesis, scenario analysis, and measurement, reporting, and verification (MRV) development for EW research and applications.