Global meta-analysis of irrigation scheduling effects on water use efficiency, fruit quality, and yield in blueberry and strawberry

Irrigation scheduling plays a critical role in improving water use efficiency (WUE), fruit quality, and yield of crops under increasing water scarcity and climate variability. A global meta-analysis was performed to assess WUE and crop performance of blueberry and strawberry under different irrigation scheduling approaches using climate and soil types as moderators. Irrigation scheduling was categorized as 1) over-irrigation (OI; >110% evapotranspiration (ET)), 2) full irrigation (FI) as control for comparison (90–100% ET), 3) moderate deficit irrigation (MDI; 65–90% ET), 4) severe deficit irrigation (SDI; <50%) 5) farmers practice irrigation and 6) Rainfed/no irrigation. Results indicated that irrigation scheduling across all treatments reduced blueberry and strawberry yield by −26.3% (SDI) and −40.4% (OI), respectively, while WUE improved by 17.5% and 14.2% under Rainfed conditions in blueberry and strawberry. Regarding climate types, yields were reduced by −8.0% and −2.0%, and WUE improved by 10.4% and 26.7% under MDI in semi-humid climates in blueberry and strawberry, respectively. Across soil types, blueberry yield was reduced by −6.8% and −8.3% in loamy and sandy soils under MDI. Strawberry yield was reduced by −6.1%, while WUE improved by 24.9% in loam soil under MDI. Yield was slightly reduced, while WUE improved in both crops under MDI in semi-humid climate with loamy and sandy soils. We also found that irrigation scheduling significantly influenced WUE and yield, with climate and soil type strongly affecting crop response. This highlights the need for irrigation management strategies to be established on a climate- and soil-specific basis. The results of this global meta-analysis suggest that MDI could be the best option to optimize blueberry and strawberry yield under semi-humid climate and loamy soil while improving WUE under limited water availability.