Soil water status and growth of tomato with partial root-zone drying and deficit drip irrigation techniques

This study addresses water-saving irrigation strategies, including deficit irrigation (DI) at 70% and 50% crop evapotranspiration, ETc (DI70 and DI50, respectively), and partial root-zone drying (PRD) at 70% and 50% ETc (PRD 70 and PRD 50, respectively) to investigate the response of the tomato (Lycopersicon esculentum L.) using a surface drip system in the field on a sandy loam soil during years 2017 and 2018. Full irrigation (FI) at 100% ETc was used as the control treatment. Results revealed that the soil water content values for the DI and PRD treatments were lower than those in the FI treatment. The net photosynthesis rate, stomatal conductance, and transpiration rate decreased with decreasing irrigation water, whereas the xylem abscisic acid content increased. A significant decrease in fresh and dry vegetative parts for DI and PRD treatments was detected compared to the FI treatment in 2017, whereas there were no significant differences in 2018. Both DI70 and PRD70 treatments had fresh and dry tomato yields similar to the ones in the FI treatment, whereas the corresponding yields were significantly lower under DI50 and PRD50 treatments. This resulted in a water productivity increase by, on average, 28.15% and 38.24%, for DI70 and PRD70 treatments, respectively, compared to the FI treatment. The DI and PRD treatments significantly affected the tomato fruit quality. Fruits under DI and PRD treatments accumulated higher amounts of total soluble solids, vitamin C, and titratable acidity compared to FI Fruits. Therefore, the use of water-saving practices is feasible for tomato production in areas where water supply is limited.