Land Surface Modeling as a Tool to Explore Sustainable Irrigation Practices in Mediterranean Fruit Orchards

• Published in: Water resources research Vol. 60; no. 7
• Main Authors: Dombrowski, O., Brogi, C., Hendricks Franssen, H.‐J., Pisinaras, V., Panagopoulos, A., Swenson, S., Bogena, H.
• Format: Journal Article
• Language: English
• Published: Washington John Wiley & Sons, Inc 01.07.2024
• Subjects: Agricultural production; Atmosphere; Availability; Climate; Climate models; Crop yield; Crops; Data transmission; Fluxes; fruit orchards; Irrigation; Irrigation effects; Irrigation practices; Irrigation scheduling; Irrigation water; land surface modeling; Land surface models; model development; Modelling; Moisture content; Orchards; Plant water; Regional analysis; Regional development; Regional planning; Representations; Rivers; Schedules; Simulation; Soil; Soil moisture; Soil stresses; Soil water; Transpiration; Uncertainty; Water availability; Water management; Water resources; water resources management; Water stress; Water use
• ISSN: 0043-1397; 1944-7973
• DOI: 10.1029/2023WR036139

Irrigation strongly influences land‐atmosphere processes from regional to global scale. Therefore, an accurate representation of irrigation is crucial to understand these interactions and address water resources issues. While irrigation schemes are increasingly integrated into land surface models, their evaluation and further development remains challenging due to data limitations. This study assessed the representation of field‐scale irrigation using the Community Land Model version 5 (CLM5) through comparison of observed and simulated soil moisture, transpiration and crop yield. Irrigation was simulated by (a) adjusting the current irrigation routine and (b) by implementing a novel irrigation data stream that allows to directly use observed irrigation amounts and schedules. In a following step, the effect of different irrigation scenarios at the regional scale was simulated by using this novel data stream. At the plot scale, the novel irrigation data stream performed better in representing observed SM dynamics compared to the current irrigation routine. Nonetheless, simplifications in crop and irrigation representation and uncertainty in the relation between water stress and yield currently limit the ability of CLM5 for field‐scale irrigation scheduling. Still, the simulations revealed valuable insights into model performance that can inform and improve the modeling beyond the field scale. At regional scale, the simulations identified irrigation priorities and potential water savings. Furthermore, application of LSMs such as CLM5 can help to study the effects of irrigation beyond water availability, for example, on energy fluxes and climate, thus providing a powerful tool to assess the broader implications of irrigation at larger scale. Plain Language Summary Irrigation impacts how land and atmosphere interact, both locally and globally. Therefore, it is important to understand the effects of irrigation practices and improve how water resources are managed. Advanced models such as land surface models now include irrigation. However, developing these models is difficult due to limited data. This study used the Community Land Model version 5 (CLM5) to compare observed and simulated soil moisture, plant water use, and crop yield. Two methods were used: an updated irrigation routine and a new data stream that uses actual irrigation amounts and schedules. The new data stream more accurately represented soil moisture. Simplifications in how the model handles crops and irrigation, and uncertainty about the link between water stress and yield, limit CLM5's effectiveness for precise irrigation planning. Still, the simulations provided valuable insights into the model's performance. At a regional level, the simulations highlighted key areas for irrigation and potential water savings. Models like CLM5 can help study the effects of irrigation on water availability, energy fluxes, and climate, making them useful tools for improving water management and allocation. Key Points The CLM5 irrigation routine is tested at different scales and enhanced with the option to prescribe irrigation amounts and schedules Soil moisture dynamics were simulated well but model simplifications limit the ability of CLM5 for field‐scale irrigation scheduling Regional simulations using different irrigation scenarios identified priorities and water savings for improved irrigation management