Yield and quality response of sweet corn under drought stress in semi-arid conditions: a comparison of field measurements and CROPWAT model estimates

Abstract

Abstract This study examined the effects of drought stress on sweet corn yield, morphological traits, water use efficiency, and chemical composition under semi-arid climatic conditions. Field experiments were carried out in 2022 and 2023, using a randomized complete block design with three replications. Two irrigation levels were tested: full irrigation (FI) and deficit irrigation (DI) at 50 % field capacity. Actual evapotranspiration (ETa) ranged from 360 to 615 mm across both years. Water use efficiency (WUE) varied between 0.79 and 1.00 kg/m3, and irrigation water use efficiency (IWUE) ranged from 0.94 to 1.44 kg/m3. Grain yield varied from 3530 to 5170 kg/ha depending on irrigation regime. Other yield components such as ear length (12.8–17.0 cm), grain number per ear (412–538), grain weight per ear (40–57 g), thousand-kernel weight (104–135 g), and hectolitre weight (39–54 kg) also showed significant variation. The CROPWAT model estimations of crop evapotranspiration (ETc) were generally consistent with observed values but showed discrepancies under deficit irrigation. Morphological parameters declined significantly under drought stress. Irrigation levels also influenced chemical composition. Quality parameters ranged as follows: protein (8.7–9.0 %), oil (10.7–12.6 %), ash (1.09–1.28 %), starch (33.7–39.2 %), and crude fibre (6.0–7.4 %). Higher starch and fibre contents were observed under full irrigation. The results highlight the impact of irrigation strategies on both yield and quality components of sweet corn over two growing seasons.