Optimizing water demand in citrus orchards: a novel model using evolutionary algorithms on Sentinel-1 time series data

Citrus fruits are crucial globally, impacting economies and livelihoods. However, climate change is affecting water availability and usage, posing challenges for managing water in citrus crops. This paper introduces CARP-flux, a new model designed to assess water needs in citrus orchards, specifically addressing the limitations of traditional methods under changing climates. The study was conducted in El Hundido, an irrigation village located in the Vega del Guadalquivir Valley near Cantillana, Seville (Spain), acknowledged as a significant citrus trade area at both the European and national levels. To adjust the model to contemporary climate conditions, time-series data from the Sentinel-1 Interferometric Wide (IW) satellite (VV and VH polarizations) from 2021 and 2022 were employed. Employing genetic algorithms and the Weibull distribution, the study incorporated 3D radiation models from backscatter data, a spatial interpretation of water and radiation dynamics, which, in turn, validated CARP-flux’s performance. This model proved effective in identifying land-use changes and evaluating radiation intensity, which are critical factors for understanding crop water needs in climate change scenarios. CARP-flux offers a precise alternative to the conventional Hargreaves technique for citrus groves, which underestimates water requirements in irrigated and humid regions with ample soil moisture, such as the Vega del Guadalquivir.