Date of Graduation

5-2023

Document Type

Dissertation

Degree Name

Doctor of Philosophy in Plant Science (PhD)

Degree Level

Graduate

Department

Horticulture

Advisor/Mentor

Michael Richardson

Committee Member

Douglas Karcher

Second Committee Member

Brian Haggard

Third Committee Member

Ryan Dickson

Fourth Committee Member

William Berndt

Keywords

Irrigation, Nanobubbles, Turfgrass

Abstract

Nanobubbles (NBs) are sub-micron, stable cavities of gas. The properties of NBs theoretically allow long bubble residence times and high gas dissolution rates resulting in the supersaturation of oxygen in water. Adequate soil aeration is a constant concern for producers of agricultural and horticultural crops. Because of their unique properties, NBs have been investigated for oxygenating water used in the irrigation of various agricultural and horticultural crops to increase soil oxygen concentration. Creeping bentgrass (Agrostis stolonifera L.) is the most widely used turfgrass for golf course putting green surfaces. Golf course superintendents use various methods to increase soil oxygen in putting green root zones, such as core aerification, solid-tine aerification, and sand topdressing. An alternative method of delivering oxygen to the soil could be through irrigation with NB-oxygenated irrigation water (NOIW). The objectives of this research were to 1) Examine the effect of time and temperature on the dissolved oxygen content of NOIW sources, 2) examine the effects of NOIW on infiltration, soil oxygen concentration, soil organic matter, and plant performance of a creeping bentgrass putting green, and 3) examine the effects of subsurface irrigation with NOIW on plant performance of creeping bentgrass grown in sand-based lysimeters. Four treatments included potable water, irrigation pond water, and potable and irrigation pond water oxygenated using a membrane-based NB injection system. Nanobubble oxygenation of water failed to increase the retention time of dissolved oxygen compared to a standard oxygenation method, regardless of water temperature. Nanobubble-oxygenated water did not affect creeping bentgrass plant performance in either field or laboratory settings. Nanobubble-oxygenated water increased soil oxygen in one season, but this effect was not repeatable. The organic matter content of a sand-based creeping bentgrass putting green was unaffected by irrigation with NB-oxygenated water. Nanobubble oxygenation remains an excellent means of efficiently oxygenating large volumes of water, although plant responses to the water were negligible. Future research investigating the irrigation of other agricultural and horticultural crops is warranted as the understanding and depth of knowledge surrounding NB technology continue to improve.

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