Deployment of Eddy Covariance System to Quantify Actual Crop Evapotranspiration of Summer Cover Crop Sesbania and Subsequent Crops under Desert Conditions at Yuma Agricultural Center

Cover crops such as Sesbania (Sesbania punicea) are adopted for their benefits in nitrogen fixation, soil organic matter enhancement, and weed suppression. However, empirical data quantifying the actual crop evapotranspiration (ETc) of Sesbania under desert conditions are limited. This makes it difficult to assess all costs and benefits of growing cover crops in the Yuma region, and particularly reduces the ability to optimize irrigation scheduling and water budgeting. This limitation can be addressed by using Eddy Covariance (EC) flux stations, which are instruments that provide a direct, non-invasive, high-frequency measurement of crop ETc at field scale. EC systems are advanced meteorologic instruments that measure net radiation and water vapor fluxes at high frequencies, enabling the quantification of crop water use at hourly, daily, and full-season time scales ETc obtained from the EC stations will provide document water use patterns for cover crops, facilitate improved water resource management practices, and enable crop coefficient development tailored for the Yuma region.