Biological Systems Engineering, Department of


First Advisor

Xin Qiao

Second Advisor

Derek M. Heeren

Third Advisor

Matteo D'Alessio

Date of this Version

Summer 7-29-2022

Document Type



Gonzalez, H. 2022. Studies on Air Injection in a Wastewater-Fed Subsurface Drip Irrigation System. Biological Systems Engineering – Dissertations, Theses, and Student Research.


A THESIS Presented to the Faculty of The Graduate College at the University of Nebraska In Partial Fulfillment of Requirements For the Degree of Master of Science, Major: Mechanized Systems Management, Under the supervision of Professor Xin Qiao. Lincoln, Nebraska: July 2022

Copyright © 2022 Henry Alexander Gonzalez Hernandez

Chapter 1 is under review in the Journal of Irrigation and Drainage Engineering, American Society of Civil Engineers (ASCE)


In 2020, the Ogallala High Plains Aquifer supplied irrigation water for approximately 3.6 million hectares in Nebraska, making it the most irrigated state in the United States. Although Nebraska is highly dependent in groundwater, locations included in the Gering-Fort Laramie Irrigation District (border of Nebraska and Wyoming) rely on surface water resources. In addition to these conventional water sources, using non-conventional alternatives for crop production can be just as important during water shortage times such as the one that e occurred in 2019 with the collapse of the Goshen/Gering-Fort Laramie Canal. Feedlot runoff presents a great opportunity in Nebraska, but it can become a point source pollution of pharmaceutical and personal care products, which could be accumulated in plant tissues and soil.

In Chapter 1, we tested how passive air injection to the wastewater-fed SDI system could improve crop yield by increasing soil oxygen content at the root zone. Therefore, the objective of Chapter 1 was to evaluate the effect of air injection on corn and sugar beets yield when using feedlot runoff irrigation in SDI. Results have shown that passive air injection has been effective increasing soil oxygen content in shallow depth. Air injection did not affect sugar beet yield or sucrose content in any growing season, but significantly increased corn yield in the 2021 growing season. In Chapter 2, we evaluated the effects of air injection into subsurface drip irrigation on the soil microbial diversity and the residual of antibiotic residues accumulated in soil pore water, soil, and plant matrices. The objective of Chapter 2 was to evaluate the effects of air injection on the reduction of antibiotic concentrations in the soil environment introduced by irrigation with feedlot wastewater. Results have shown that air injection was not effective in removing or treating antibiotics such as sulfamethoxazole or monensin Na. However, in air-injected sugar beet or corn plots, some microbes had a significantly higher abundance than in non-air-injected plots, revealing potential benefits for crop production.

Advisor: Xin Qiao.