Importance of Breakthrough
For most growers in drier climates, irrigation is the most significant variable to the success of their harvests. Over-irrigation can negatively impact soil and crop quality, and waste money when nutrients that crops need to thrive are lost through leaching and runoff. Evapotranspiration (ET), the movement of water from the earth’s surface, through plant transpiration and soil evaporation into the atmosphere, is a key parameter used to estimate real-time crop water need, information that can be used to better manage irrigation. For researchers, ET is also a critical indicator for managing plant health, understanding crop water use and monitoring drought. Among several methods available to measure ET, eddy covariance towers are the most direct and accurate. Eddy covariance determines the movement of water vapor in the atmosphere, carbon dioxide exchanges and wind velocity. Eddy covariance towers can provide critical ground-truthing data needed to calibrate other ET estimation methods such as satellite-based energy balance models.
A challenge that many land-grant universities and irrigation manufacturers have grappled with is how to help farmers adopt the practice of using ET measurements into their daily management routines. While Eddy covariance towers are the most accurate method, they are extremely expensive and lack the accessibility and mobility that satellite-based tools offer. On the other hand, the software in satellite-based tools rely on routine calibration in order stay within an acceptable level of accuracy to be useful in irrigation management. Christopher Neale, the Director of Research at the Daugherty Water for Food Global Institute, University of Nebraska is working to bring the best of these tools together.
Since 2016, the Daugherty Water for Food Global Institute at the University of Nebraska, with additional funds from the IIC and collaboration with industry partners Li-COR Biosciences and The Climate Corporation, has instrumented 10 Eddy covariance towers in Iowa, Nebraska, Kansas and Colorado with additional equipment to process data in real time and provide corrected ET values online. The towers run along the 41st Parallel North, a circle of latitude that runs through the central United States, and thus this project was aptly named the Parallel 41 Flux Network. Bringing the network of towers through the central U.S. is a critical first step to build a mobile app to bring “research-grade” data to farmers and eventually provide real time corrected daily satellite-based ET from the GLoDET product in an easy-to-use device. In the meantime, farmers within range of the towers can use the data to calibrate and check the information they may have from more affordable satellite-based tools.
Details about this breakthrough
So far, 10 Eddy covariance towers have been instrumented or installed in Iowa, Nebraska, Kansas and Colorado. While a single tower is traditionally used to validate research from university experiment stations, the growing network of towers is already being used to engage state and water district leaders, Natural Resources District staff and producers across the Great Plains in dialogue about better water management decisions, both for individual farmers and basin-wide policies. In the future, the Parallel 41 network could be used to improve the Evaporative Stress Index used in detection and early warnings about drought.
The Foundation for Food & Agriculture Research (FFAR) launched the Irrigation Innovation Consortium (IIC) in 2018 with a $5 million commitment, which was matched by consortium participants for a $10 million investment supporting pioneering irrigation research.
Through the IIC, industry and the public sector co-develop and test equipment, technology and information systems to equip farms of the future with pioneering technology and effective strategies to improve irrigation management and water-use efficiency.