# Long‐Term Elevated CO2 Improves Soil Health and Rice Yields in Paddy Fields

## TL;DR

Long-term exposure to elevated CO2 improves soil health and rice yields in paddy fields, supporting food security and ecosystem functions.

## Contribution

Combines long-term experiments and global data to show sustained CO2 fertilization effects on paddy soils.

## Key findings

- Long-term elevated CO2 significantly improves soil health in rice paddies.
- Paddy soils benefit more from eCO2 than other terrestrial ecosystems.
- Elevated CO2 sustains rice yield gains over decades.

## Abstract

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.

Combining the two longest‐running rice free‐air CO2 enrichment experiments with a global data synthesis, this study demonstrates that long‐term elevated CO2 consistently enhances soil health. In rice paddies, this improvement sustains the CO2 fertilization effect over decades. Proactive measures to avert potential phosphorus deficiency and soil acidification are essential, allowing healthier soils to further reinforce future food security.