The over‐exploitation of groundwater in agriculture necessitates the adoption of water‐efficient practices. A field study (2020–2022) under cotton–wheat cropping in semi‐arid Punjab, India, evaluated subsurface drip irrigation (SSDI) with lateral depths (20, 25 and 30 cm), emitter spacings (20, 30 and 40 cm) and irrigation levels (60%, 80% and 100% ETc). Bayesian optimization was used for multicriteria decision‐making. The res...