Crop Water Requirement Estimated with Data-Driven Models Improves the Reliability of CROPWAT 8.0 and the Water Footprint of Processing Tomato Grown in a Hot-Arid Environment

Abstract

The determination of the actual crop water requirement (CWR) today represents an important prerogative for combating climate change. A three-year trial was conducted to ad-dress the need to provide adequate support to processing tomato growers in defining the correct amounts of water to be supplied. In fact, the objective of this work was to calculate the water requirement of processing tomatoes, specifically analyzing their irrigation needs using the CROPWAT 8.0 software and through capacitive and tensiometric probes. Furthermore, for both methods, the tomato yield was evaluated both by supplying 100% of its water requirement and by supplying, through regulated deficit irrigation (RDI), 70% of its water requirement. Subsequently, for each irrigation strategy employed and for each CWR calculation method, the water footprint was calculated by analyzing the blue, green, and grey components. In the years 2022 and 2023, there was an overestimation of CWR of 13.5% for IR100 and 13.94% for IR70, and 14.53% for IR100 and 11.65% for IR70, respectively, while in 2024 there was an underestimation, with values of 9.17% and 5.22% for the IR100 and IR70 treatments compared to the values obtained with the probes. The total WF of tomatoes varied between 33.42 and 51.91 m3 t−1 with the CROPWAT model and between 35.82 and 47.19 m3 t−1 with the probes for IR100, while for RDI70, the values ranged between 38.72 and 59.44 m3 t−1 with the CROPWAT method and between 35.81 and 53.95 m3 t−1 with the probe method. In water-scarce regions, integrating the CROPWAT 8.0 model (enhanced with real-world data) and implementing smart systems can significantly improve water management, refine decision-making processes, and mitigate environmental impacts. This approach directly addresses the urgent need for water security within sustainable agriculture.