Date of Award

8-2016

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Plant and Environmental Science

Committee Member

Dr. Haibo Liu, Committee Chair

Committee Member

Dr. Lambert McCarty

Committee Member

Dr. James Rieck

Abstract

Traffic is a significant force at play on turfgrasses, especially on sports fields and golf courses. Previous studies have characterized the effect of traffic in the morning at 0700 HR and 0900 HR on golf course greens when the turfgrass canopy temperature is below freezing (0◦C) (Baldwin et al., 2008). This study was performed to determine the effect, if any, of traffic at 0800 HR on a ‘Crenshaw’ creeping bentgrass (Agrostis stolonifera L.) putting green when the turfgrass canopy temperature was below freezing. The study was also initiated to determine if afternoon traffic at 0300 HR on the same day as the morning traffic had an impact on the turfgrass playability, performance, and health. In addition, potassium (K) is a required plant nutrient that is often applied to turfgrasses, especially creeping bentgrass, in order to help the plant tolerate stresses. It has been suggested that fall K fertilization can aid in creeping bentgrass winter traffic tolerance, but research on the subject is limited and inconsistent. This experiment was also conducted to investigate the performance of creeping bentgrass under varying K fertilization levels in conjunction with different morning and afternoon traffic levels when the turfgrass was grown in the transition zone of the southeastern United States. A two year repeated field experiment was conducted from 1 October 2014 and 2015 to 30 April 2015 and 2016 to investigate the effect fall-applied supplemental K fertilization, morning traffic (when the turfgrass canopy temperature was below freezing), and afternoon traffic (applied the same day as the morning traffic) had on visual turfgrass quality, shoot chlorophyll , normalized difference vegetative index (NDVI), ball roll, surface firmness, soil volumetric water content, soil bulk density, soil organic matter levels, soil K concentration, and tissue K concentration of ‘Crenshaw’ creeping bentgrass. Treatments consisted of three supplemental K rates (0, 3.66, and 7.33 g m-2 yr -1), three morning traffic rates (0, 4, and 8 passes with a modified water-filled push turfgrass roller that weighed 74.84 kg and applied a force of 1.34 kg cm-2), and two afternoon traffic rates (0 and 6 passes with the same roller). There were no significant differences between the visual turfgrass quality ratings for the two repeated years that the study was performed, so the results are pooled between both years. Visual turfgrass quality was significantly lower for plots that received 4 passes with the roller in the morning when compared to plots that received 0 passes with the roller in the morning on 15 January, 01 February, 15 February, 01 March, and 15 March. Visual turfgrass quality was also significantly lower for plots that received 8 passes with the roller in the morning when compared to plots that received 0 passes with the roller in the morning on 15 January, 01 February, 15 February, 01 March, and 15 March. Additionally, turfgrass quality was significantly lower for plots that received 8 passes with the roller in the morning when compared to plots that received 4 passes with the roller in the morning on 15 February and 01 March. There were no significant differences between the shoot chlorophyll indexes for the two years that the study was performed, so the results are pooled between both years. Shoot chlorophyll index was significantly lower for plots that received 0 passes with the roller in the afternoon when compared to plots that received 6 passes with the roller in the afternoon on 01 April and 15 April. As with visual turfgrass quality and shoot chlorophyll index, there was not a significant difference between the NDVI readings for each year of the study, so the results are pooled from both years’ data. NDVI was significantly lower for plots that received 4 passes with the roller in the morning when compared to plots that received 0 passes with the roller in the morning on 15 January, 01 February, 15 February, 01 March, and 15 March. NDVI was also significantly lower for plots that received 8 passes with the roller in the morning when compared to treatments that received 0 passes with the roller in the morning on 15 January, 01 February, 15 February, 01 March, and 15 March. Additionally, NDVI was significantly lower for plots that received 8 passes with the roller in the morning when compared to plots that received 4 passes with the roller in the morning on 15 February. Like the other parameters, there were no significant differences between the ball roll for the two years that the study was performed, so the results are pooled between years I and II. Ball roll was greater during the colder months with the least amount of turfgrass tissue growth, and this trend was demonstrated at all treatment levels. On 15 January and 15 February, ball roll was higher for plots that received 0 passes with the roller in the morning and 6 passes with the roller in the afternoon when compared to plots that received 0 passes with the roller in the morning and 0 passes with the roller in the afternoon. Additionally, ball roll was significantly lower for plots that received 0 passes with the roller in the morning and 0 passes with the roller in the afternoon when compared to plots that received either 4 or 8 passes with the roller in the morning and 0 passes with the roller in the morning on the same dates. Again, there were no significant differences in surface firmness readings between the two years of the study, but for the pooled data from years I and II, surface firmness was significantly greater for plots that received 8 passes with the roller in the morning when compared to plots that received 0 passes with the roller in the morning on 15 February. Overall, traffic treatments, especially those applied in the morning at 0800 HR, had a significant impact on creeping bentgrass health and appearance. Supplemental K did not show any significant effect on turfgrass health. Even with the damage that occurred in the colder winter months, the turfgrass had recovered to acceptable quality by the spring-time months when temperatures warmed.

Share

COinS