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ARS Home » Plains Area » Fort Collins, Colorado » Center for Agricultural Resources Research » Water Management and Systems Research » Research » Publications at this Location » Publication #397910

Research Project: Improving Crop Performance and Precision Irrigation Management in Semi-Arid Regions through Data-Driven Research, AI, and Integrated Models

Location: Water Management and Systems Research

Title: Using remote sensing to inform crop coefficient based irrigation scheduling under deficit irrigation

item DeJonge, Kendall
item Zhang, Huihui

Submitted to: Environmental and Water Resources Institute World Congress Proceedings
Publication Type: Abstract Only
Publication Acceptance Date: 10/17/2022
Publication Date: N/A
Citation: N/A

Interpretive Summary: N/A

Technical Abstract: Reference evapotranspiration (ETref, specifically ETo or ETr) calculated from local mesonets can be used in combination with crop coefficients to estimate crop ET (ETc) demand. However, estimating crop coefficients under deficit or limited irrigation is more complex. These coefficients, the basal (Kcb, the ratio of transpiration to ETref) and water stress (Ks, transpiration reduction) coefficients, become dynamic and highly variable under water stress, and are best estimated from field observations including soil water content, canopy cover, and other indicators of water stress such as canopy temperature. Here we demonstrate a field experiment at the Limited Irrigation Research Farm in Greeley, CO, where we used canopy cover data obtained from imaging and canopy temperature obtained by infrared thermometers to estimate daily Kcb and Ks, respectively. Current experiments also integrate unmanned aerial vehicle (UAV) obtained spatial data, as well as numerical crop modeling information, as well as comparing to FAO-56 based scheduling. Results, opportunities, and challenges of these techniques are shown in this talk. These techniques have potential to optimize irrigation management in precision irrigation applications, including variable rate irrigation on center pivots.