Assessment of irrigation effects on consumptive water use under varying warming scenarios through the lens of multiple evapotranspiration models: implications on the sustainability of water resources of an intensive irrigation valley in Northwestern Mexico

Abstract:

The intensive use of irrigation in arid and semi-arid areas has increased due to food consumption from a growing population. Furthermore, the pressure exerted by global warming on these irrigated production systems tests the efficiency of different irrigation methods. More efficient irrigation techniques and crop water planning are urgently needed. In this work, several methods to estimate actual crop evapotranspiration (ET_a), using meteorological data, high resolution remote sensing data and canopy surface temperature as input, have been proposed to monitor water consumption by irrigated winter wheat (Triticum durum) under current ambient conditions and warming-induced plots. The main goal of this study is to assess the implications of the technological improvements on the common irrigation management used by farmers. The experiment was carried out in the Yaqui Valley, one of the most important intensive agricultural regions located in the Northwestern Mexican State of Sonora, within an experimental plot. A dense network of thermal radiometers monitoring canopy surface temperature, a proxy of plant water status, was deployed on the field under standard and warming-induced conditions. Additionally, seven UAV-flights were carried out at different phenological stages of wheat development to generate high resolution thermography and Normalized Difference Vegetation Index surveys. Surface energy components and meteorological observations were measured using the Eddy Covariance technique. All these datasets were integrated with the Operational Simplified Surface Energy Balance (SSEBop) model and the Maximum Entropy Production (MEP) approach to estimate actual crop consumptive water use. Both SSEBop and MEP models performance was assessed by comparing model ET outputs with observations from the EC instruments. Preliminary results, show a good agreement between model outputs and EC observations. Furthermore, warming-induced conditions suggest an increase in water demand by crops, thus, global warming conditions exerted more pressure on water resources used for intensive agricultural systems. This work explores possible scenarios of water consumption under a warming future to design more sustainable water planning and management in agricultural areas of arid regions.