Response of maize to supplemental irrigation and other agronomic practices in different regions of China: A meta-analysis

Maize is the most widely cultivated crop in China. However, droughts pose significant challenges to the sustainable development of China’s maize. Under the condition of limited water supply, reasonable supplementary irrigation is an effective measure to alleviate maize drought and increase yield. We conducted a meta-analysis based on 82 field studies and 2836 data pairs to evaluate the effects of supplemental irrigation on maize yield and crop water productivity (WP c ) in China. This study revealed that supplemental irrigation increased maize yield by 17.5 % across China. Annual precipitation, average temperature, maize variety, and irrigation amount significantly influenced yield responses. Yield gains after supplemental irrigation decreased (p < 0.01) as annual precipitation and temperature increased. Regionally, the highest yield improvements were observed in Northwest China (20.08 %), followed by the Huang-Huai-Hai Plain (17.01 %) and North China (16.37 %) (p < 0.05). Yield gains after supplemental irrigation were mainly due to the increases in grain number (10.67 %) and grain weight (9.28 %), while supplemental irrigation has no effect on ear number. Although supplemental irrigation increased maize water consumption (ET a ), it had not signific a ntly effect on WP c , its with effects on WP c varied by region, with significantly improvements in Northwest China but no reductions in the Huang-Huai-Hai Plain and North China. Additionally, newer high-yielding maize varieties showed greater yield increases with supplemental irrigation than older varieties. Across regions, a single supplemental irrigation of 50 mm was deemed most appropriate. This study offered strategies for optimizing irrigation management strategies in China’s maize-producing areas. • The application of supplemental irrigation increased maize yield by 17.5 % across China. • It increased grain numbers per cob (10.7 %) and their weight (9.3 %). • The highest yield improvements were observed in Northwest China (20.08 %) • Yield gains decreased with growth period precipitation and annual temperature increased • High yielding varieties responded better to supplemental irrigation than older varieties.