Abstract BACKGROUND Water scarcity and soil salinization are major constraints to irrigated agriculture in semi‐arid regions, affecting crop productivity and fruit quality. Combining deficit irrigation with biostimulant application has emerged as a promising strategy to improve water use efficiency and plant stress tolerance. This study evaluated the effects of irrigation levels and amino acid‐based biostimulant rates on physiological responses, yield, and postharvest quality of melon ( Cucumis melo L.) grown under semi‐arid conditions. RESULTS The experiment was conducted during the rainy, transition, and dry seasons of 2023 using a randomized block design with three irrigation levels (50%, 75%, and 100% of soil available water) and four biostimulant rates (0, 4, 6, and 8 L ha −1 ). Stomatal conductance (gs) and leaf temperature (LT) were monitored during the crop cycle, while yield and fruit quality attributes were evaluated at harvest. Irrigation at 75% of available water resulted in yields comparable to those obtained with full irrigation, exceeding 34 Mg ha −1 while reducing water input. The application of 4 L ha −1 of biostimulant increased melon productivity by up to 32.58% compared with the control treatment. Increasing biostimulant rates promoted reductions in gs, suggesting improved stomatal regulation under stress conditions, while LT remained stable across treatments. Fruit quality parameters were maintained even under saline conditions and deficit irrigation. CONCLUSION Moderate deficit irrigation combined with optimized biostimulant application improves melon tolerance to water and salt stress without compromising fruit quality. This strategy enhances water use efficiency and represents a sustainable alternative for melon production in semi‐arid environments. © 2026 The Author(s). Journal of the Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.
Calaça et al. (Tue,) studied this question.