Date of Graduation

12-2019

Document Type

Thesis

Degree Name

Master of Science in Horticulture (MS)

Degree Level

Graduate

Department

Horticulture

Advisor/Mentor

Douglas Karcher

Committee Member

Kristofor Brye

Second Committee Member

Michael Richardson

Keywords

Cultivar, Drought, Evapotranspiration, Irrigation, Turfgrass, Water

Abstract

Turfgrass lawns are commonly utilized for home and commercial applications because of the aesthetic, environmental, and recreational benefits grasses provide, but many people perceive turfgrass as solely an aesthetic benefit that requires significant water inputs. It is important to identify and use turfgrass cultivars that have known drought tolerance, and also fine-tune and throughout development. A series of field experiments were conducted to determine the water requirements of turfgrass lawn systems with the following objectives: 1) investigate differences in chronic drought resistance and irrigation recommendations among cultivars of Kentucky bluegrass (Poa pratensis L.) and tall fescue (Festuca arundinacea Schreb.) 2) determine the water use of Kentucky bluegrass as affected by cultivar, irrigation frequency, and soil texture; 3) and determine the reference evapotranspiration (ETo) percent replacement that maximizes bermudagrass (Cynodon dactylon [L.] Pers.) establishment from seed and whether Turfgrass Water Conservation Alliance qualified cultivars require less water to establish from seed. From the cultivars evaluated, PST-K13-137 and NAI-13-132 Kentucky bluegrasses were the most drought tolerant and drought susceptible cultivars, respectively, and the tall fescue cultivar Thunderstruck was the most drought tolerant and Titanium 2LS was the most drought susceptible. For both species, there were no significant differences in cumulative water requirements, likely be due to the lack of inclusion of experimental controls with known drought tolerance. Lysimeters plots irrigated to replace 40% ETo and containing loamy sand resulted in less green turfgrass coverage than those grown in silt loam. Water use was significantly affected by soil texture only during late summer 2018, with lysimeters containing silt loam and loamy sand using 23.8 and 22.5 mm per week, respectively. These results imply that, under prolonged drought stress, soil texture has minimal effect on water consumption. Irrigating to replace 100% ETo is adequate to maximize bermudagrass establishment from seed. These conclusions validate the global water-saving potential when drought tolerant cultivars and precise irrigation recommendations are implemented.

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