Lead Researchers: Jose Chavez, Daran Rudnick,
Juan Enciso, Florence Cassel
Contact: José Chávez
Industry Partner: Lindsay Corporation 

Abstract:
Unmanned Aerial Systems (UASs) and satellites have been recognized as excellent platforms to provide near real-time feedback of temporal and spatial conditions found in agricultural fields throughout the growing season. UASs have also allowed selecting the best management practices that optimize the management of soil and water resources. The main objective of this study is to assess the accuracy of using UASs and satellites (multispectral imagery) to determine crop actual water use and soil water deficit. This study will be conducted at two research facilities in Colorado, one research station in NE, at a commercial orchard and in Weslaco, TX, one research site in Garden City, KS; and at commercial farms in Fresno, CA. Remote sensing (RS) imagery (0.05 – 5 m pixel size) will be acquired over research fields to determine crop evapotranspiration (ET) and soil water deficits on a daily basis. Eddy covariance and soil water sensors/probes will be used to assess remote sensing platform and crop ET model (e.g., reflectance crop coefficient, energy balance) weekly, monthly, and seasonal accuracy.

Reduced water supply due to drought, urban growth, and industry demand has increased the need for efficient water management. Satellite and UAS platforms equipped with advanced multispectral sensors offer very high spatial and temporal resolution that can be used to support farmers in making effective irrigation management decisions. 

PlanetDove imagery (3m pixel spatial resolution) was downloaded and processed on a regular basis for research fields in CO (Greeley and Akron) and NE (North Platte), and in Texas. Acquiring UAS data has proven to be difficult due to hardware, software, and weather issues (e.g., wind, clouds). The COVID-19 pandemic slowed research in 2020 due to safety protocols. Work will continue in 2021 with collaborators in CO, NE, TX, and CA to complete the data collection and interpretation.  

Researchers tested the accuracy of Unmanned Aircraft Systems (UAS) combined with satellite images to determine actual water needs and soil water deficit, for both full and deficit irrigation management. A second year of research has also focused on developing novel guidelines to program the timing of irrigation.