Doctoral Dissertations

Date of Award

12-2017

Degree Type

Dissertation

Degree Name

Doctor of Philosophy

Major

Plants, Soils, and Insects

Major Professor

John C. Sorochan

Committee Members

James T. Brosnan, John C. Stier, Jaehoon Lee

Abstract

Soil water content (SWC) influences the consistency and performance of athletic fields. Two studies were conducted at the University of Tennessee Center for Athletic Field Safety (Knoxville, TN) to determine SWC impact on the performance of hybrid bermudagrass [Cynodon dactylon (L.) Pers. x C. transvaalensis, Burtt-Davy, ‘Tifway’] on silt loam (cohesive) and sand root zone conforming to United States Golf Association (USGA) specifications (noncohesive) root zones. Soil water content treatments for the cohesive soil averaged 0.10 m3/m3 (+/- 0.035), 0.17 m3/m3 (+/- 0.035), 0.26 m3/m3 (+/- 0.035), and 0.35 m3/m3 (+/- 0.005); comparatively, SWC on the non-cohesive root zone averaged 0.08 m3/m3 (+/- 0.03), 0.16 m3/m3 (+/- 0.03), and 0.25 m3/m3 (+/- 0.05). To determine the effects of SWC on wear tolerance of hybrid bermudagrass, plots were subjected to 50 traffic events annually with the Baldree traffic simulator. For the cohesive soil, the highest SWC treatment (0.35 m3/m3) lost green turfgrass cover (GTC) four times faster than plots averaging 0.10 m3/m3 or 0.17 m3/m3. However, noncohesive root zones saw minimal differences in GTC loss among SWC treatments. Results indicated, for both root zones, that surface hardness was inversely related to SWC. Soil bulk density increased and air-filled porosity decreased as traffic events increased for both root zone constructions regardless of SWC. Our findings indicate that 0.10 to 0.17 m3/m3 SWC means was the optimal range for hybrid ‘Tifway’ bermudagrass subjected to simulated traffic on cohesive soil, while 0.08 to 0.16 m3/m3 SWC means was the optimal range for the non-cohesive root zone. Using data from the experiments on cohesive and sand soil constructions, predictive models were created to calculate the loss of turf cover based on SWC and traffic events (P ≤ 0.05, R2 = 0.87; P ≤ 0.05, R2 = 0.91). These models will help decision makers determine hybrid bermudagrass field performance expectations under varying soil moisture conditions and traffic on both cohesive and non-cohesive root zones.

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