A Remote-Sensing-Assisted Estimation of Water Use in Rice Paddy Fields: A Study on Lis Valley, Portugal

Rice culture is one of the most important crops in world, being consumed cereal grain (755 million tons 2020). Since rice usually produced under flooding conditions and water performs several essential functions for crop, estimating its needs essential. Remote sensing techniques have shown effectiveness monitoring use crop fields. An estimation from satellite data a challenge, but could be very useful, order to spatialize local estimates operationalize production models. This study intended derive an approach estimate actual evapotranspiration (ETa) paddies temporal series images. The experimental were obtained Lis Valley Irrigation District (central coast Portugal), during 2019 2021 growing seasons. average seasonal ETa (FAO56) resulted 586 ± 23 mm productivity (WP) was 0.47 0.03 kg m−3. Good correlations found between coefficients (Kc) proposed by FAO NDVI evolution control fields, with R2 ranging 0.71 0.82 stages II+III (development + middle) 0.76 stage IV (late). results derived RS-assisted method compared values surface energy balance model METRIC, showing error ±0.8 d−1, negligible bias. findings this work are promising show potential productivity, capturing variability growing, then predicting yield, useful free tool available farmers.