Comparative Yield Response and Sugar Contents of Four Sweet Corn Varieties Under Different Shallow Subsurface Drip Irrigation Treatments

ABSTRACT This study evaluated the impacts of three water application treatments—potential evapotranspiration (PET), crop‐specific evapotranspiration (Crop‐ET) and rainfed (no irrigation)—on the growth, yield and quality of sweet corn ( Zea mays ) via shallow subsurface drip irrigation. During the 2022 growing season, the study utilised a randomised split‐plot design with four sweet corn hybrids (Ambrosia F1 SE, Temptress F1 SG, Honey and Cream F1 SU, and Peaches and Cream F1 HSE) and three irrigation replicates. PET‐based irrigation calculated using the modified Penman–Monteith equation often results in overirrigation, especially during early growth stages. In contrast, Crop‐ET, calculated with crop coefficients, more effectively matches crop water needs, improving irrigation efficiency and conserving resources. Compared with Crop‐ET plots, rainfed plots were most vulnerable to dry spells and, on average, produced ~25–35% fewer ears ha −1 and ~30–45% lower total ear mass. Peaches and Cream F1 HSE demonstrated strong resilience and biomass production under all treatments, whereas Ambrosia F1 SE presented high sugar contents but greater sensitivity to water stress. Soil texture and moisture retention significantly influenced irrigation effectiveness and water availability. These findings emphasise the importance of tailored irrigation strategies based on crop‐specific water requirements and soil properties, alongside drought‐tolerant hybrid selection, to maximise yield and improve quality in water‐limited regions. Future research should address multi‐season variability and include deeper soil moisture dynamics.