Optimizing irrigation for cherry tomato under elevated temperature and CO2: Integrating physiology, economic benefits and water-use efficiency

Climate-driven water scarcity necessitates resilient irrigation strategies for sustainable agriculture. Existing paired-factor research remains fragmented, constrained to partial growth stages and lacking integrated models that link economic benefits to physiological indicators. This study hypothesized that warming, elevated CO 2 , and irrigation level jointly regulate the physiological growth, economic benefit, and water-use efficiency of cherry tomato, and that an optimal irrigation regime could achieve a synergistic balance among the three aspects under future climate scenarios. To verify this hypothesis, this study conducted consecutive greenhouse trials across two complete growing seasons (2022 F: August 15- December 20, 2023S: March 10 - July 8), employing 12 treatments to evaluate the interactive effects of temperature (ambient /+2.3°C), CO 2 (400/800ppm) and irrigation (75%/100%/125% of crop evapotranspiration, I 0 ) on plant physiology, economic benefits, and water-use efficiency of cherry tomato. Results demonstrated that irrigation significantly regulated physiological, economic, and efficiency outcomes under different environmental conditions. Increasing irrigation significantly enhanced photosynthetic, transpiration, stomatal conductance, and fruit quality, but reduced irrigation water use efficiency (IWUE) under warming (+2.3°C). Conversely, deficit irrigation improved IWUE but restricted organ growth and dry matter accumulation. Elevated CO 2 consistently improved IWUE, whereas warming improved lycopene (+17.5%) but risked yield loss. Path analysis identified chlorophyll content and leaf dry matter accumulation as key determinants of yield and quality 100% I 0 achieved the optimal synergistic effect by maximizing economic benefits while attaining 92.6% of peak physiological development and 99.3% of maximum IWUE, thus rendering it the most recommendable irrigation regime. This study advances the theoretical basis for sustainable intensification of cherry tomato production under climate change. • Irrigation governs climate responses, regulating physiology, yield, and water-use efficiency under elevated CO 2 and Tp. • Increasing irrigation alleviated the inhibitory effect of rising Tp on yield. • Chlorophyll and leaf dry matter were core indicators for yield and quality under the interaction of Tp, CO 2 , and irrigation. • 100% I 0 irrigation optimized synergies, achieving 99.3% peak IWUE, 92.6% physiological, and maximal economic benefits.