Long-Term Elevated CO2 Improves Soil Health and Rice Yields in Paddy Fields.

Soil health underpins the productivity and ecosystem functioning of rice paddies, yet its response to elevated atmospheric CO2 (eCO2) remains poorly understood. Here, soil health responses to eCO2 are evaluated using the two longest-running rice free-air CO2 enrichment experiments, spanning 12 and 15 years. The results show that long-term eCO2 significantly improves soil health, strengthening its capacity to support crop production, water purification, and climate change mitigation. Integration of global observations further indicates that these improvements are widespread and cumulative over time, with paddy soils benefiting more than other terrestrial ecosystems. Consequently, long-term eCO2 exposure tends to enhance rice yield gains, in contrast to the productivity plateau observed in natural ecosystems. These findings provide novel and comprehensive evidence that long-term eCO2 enhances paddy soil health, improving soil multifunctionality and reinforcing the rice CO2 fertilization effect.