Quantitative Assessments of Water and Salt Balance for Cropping Systems in Lower Colorado River Irrigation Districts
Irrigation and soil salinity management are of paramount importance to agriculture sustainability in desert agriculture. Because irrigation water and shallow groundwater that fluxes up through the soil have salts, some level of excess irrigation (beyond crop consumptive use) must be applied to leach salts below the crop root zone. The various irrigation systems utilized, and the management of these systems can have a profound impact on water delivered, leaching achieved, and resulting salt distribution.
YCEDA is coordinating a large multi-institution cross-disciplinary project to quantitatively track water use and salt balance across typical crop production systems and rotations. Partners include the University of Arizona and USDA-ARS researchers, Irrigation Districts, United States Bureau of Reclamation, NASA, Arizona Commodity Councils, and others, including a group of University of Arizona-Yuma Systems Engineering seniors who completed a Senior Design project during the 2018-2019 academic year to support this project. Technologies such as electromagnetic surveys (EM38), Eddy covariance (ECV) and large aperture scintillometer (LAS) instrumentation, UAV with remote sensors, and satellites are being utilized to measure evapotranspiration (ET) and soil salinity levels at multiple scales. Data collection and analysis is ongoing. Ultimately, this unique data set will be used to develop irrigation management tools for most desert cropping systems that take into account actual crop ET and the needed leaching coefficient to assist growers to make an already efficient system even more efficient and sustainable.