Date of Award:

5-2026

Document Type:

Thesis

Degree Name:

Master of Science (MS)

Department:

Civil and Environmental Engineering

Committee Chair(s)

L. Niel Allen

Committee

L. Niel Allen

Committee

Andrew Keller

Committee

Alfonso Torres-Rua

Abstract

The State of Utah funded agricultural water optimization studies to determine how agricultural water depletion can be decreased while maintaining or improving yields. Conversion from surface irrigation to drip irrigation is investigated as a method to decrease consumptive use.

Some Utah onion producers are converting from furrow irrigation to drip irrigation to decrease water and fertilizer use and improve profits. This study compares the consumptive use and yield of three drip irrigated onion fields against the consumptive use and yield of three furrow irrigated onion fields.

Arrays of soil moisture sensors at various depths were placed in drip and furrow irrigated onion fields during 2019 and 2020. Soil moisture readings were taken every 30 minutes. Infrared radiometers were used to measure soil surface and crop canopy temperatures, allowing for estimates of evaporation from the soil surface using energy balance models. Digital flowmeters were used to measure irrigation amounts and surface runoff. Evapotranspiration (depletion) was estimated using a soil moisture budget, energy budget, and weather data. Yield measurements at the soil moisture sites were taken after the onions were lifted. Analyses of drip and furrow irrigation diversions, irrigation depletions, and yields were conducted to compare the irrigation methods.

Results showed that the furrow irrigated fields generally had a higher yield due to more uniform irrigation, however, 2 to 3 times more water was applied than on the drip irrigated fields. The drip irrigated fields had lower depletions and higher irrigation efficiencies. Results also indicate that yields in drip irrigated fields can be improved with changes in the irrigation system design and better irrigation scheduling. A literature review of similar studies, detailed methodology, and an in-depth discussion of results are presented.

Download

Share

COinS

Copyright for this work is retained by the student. If you have any questions regarding the inclusion of this work in the Digital Commons, please email us at .