Future climate resilience in rice systems of southern China: Double-cropping outperforms single-cropping in water-food sustainability

Abstract

CONTEXT

Climate warming and elevated atmospheric CO₂ concentrations, coupled with an ongoing transition from double-cropping rice systems (DCRS) to single-cropping rice systems (SCRS), are reshaping yield and hydrological processes in the subtropical monsoon regions of southern China. These concurrent shifts intensify the tension between yield stability and water sustainability under future climate scenarios.

OBJECTIVE

This study aims to evaluate the differential responses of DCRS and SCRS to future climate change, with a particular focus on rice yield and hydrological dynamics, in order to identify resilient cropping strategies under warming and CO₂ enrichment.

METHODS

An integrated modeling framework was developed for the Zishui River Basin (ZRB), a representative DCRS region in southern China. This framework combined high-resolution paddy field mapping, an enhanced Soil and Water Assessment Tool (SWAT) incorporating dynamic CO₂ response mechanisms, and multi-scenario climate projections from Coupled Model Intercomparison Project (CMIP6). Simulations were conducted under three Shared Socioeconomic Pathways (SSP) scenarios (SSP1–2.6, SSP2–4.5, and SSP5–8.5) for the periods 2041–2070 and 2071–2100.

RESULTS AND CONCLUSIONS

Under SSP5–8.5 by the end of the century, the SCRS exhibited up to 29.9 % yield loss, primarily due to heat-induced phenological shortening. In contrast, the DCRS demonstrated greater climate resilience: early rice consistently benefited from elevated CO₂ and increased thermal accumulation, resulting in robust gains in yield, while late rice, though more heat-sensitive, maintained stable productivity under moderate warming. Overall, the DCRS outperformed the SCRS, highlighting its systemic advantage in balancing water inputs with grain production.

SIGNIFICANCE

These findings emphasize the importance of embedding climate resilience into future rice production systems. Promoting double-cropping practices presents a viable adaptation pathway to enhance regional food–water sustainability under climate change.