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 ground water 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 University of Arizona and USDA researchers, Irrigation Districts, USDA-ARS, USBR, NASA, Arizona Commodity Councils and others. Technologies such as electromagnetic surveys (EM38), Eddy covariance (ECV) and large aperture scintillometry (LAS) instrumentation, UAV with remote sensors, and satellite will be deployed to measure evapotranspiration (ET) and soil salinity levels at multiple scales.
Data collection and analysis is ongoing and opportunities for more efficient water, and salt management outcomes will be identified. Ultimately, this data will be used to develop 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.