Deficit Irrigation Stabilizes Fruit Yield and Alters Leaf Macro and Micronutrient Concentration in Tomato Cultivation in Greenhouses: A Case Study in Turkey

Water is crucial for agriculture and needs to be used effectively due to climate change and drought in the Mediterranean region. For this reason, to adapt to water deficit scenarios, deficit irrigation applications are increasing in importance. The aim of this research was to determine the effect of varying levels of irrigation on growth parameters and concentration of nutrients in tomato plants grown under greenhouse conditions. The irrigation schedule used in this study was designed to include 100% (control), 90%, 80% and 70% of evaporation from the class-A pan. Water deficit was found to cause a stress effect in tomato plants, which was reflected in changes in the physiological function plants, such as flowering and early ripening. In addition, the SPAD values were examined, for which the lowest value of the green color intensity of the leaves was 47.3 (I3) and the highest was 48.7 (I4). However, the results of statistical analyses show that the difference was not significant. We also observed that the height values of tomato plants were the highest in the period of seedling and fruit ripening under full irrigation. Furthermore, analysis of the macronutrient content of tomato leaves showed that the obtained values were below the threshold values recommended for manganese. Based on these and similar studies, we believe that the application of water stress is most effective during the phases in which the plants are least affected. We believe that determining the periods during which tomato or any other crop is be affected by the least water stress will be more accurate for both plant development and economic production.