Title page for ETD etd-01172011-120802


Type of Document Master's Thesis
Author Parker, Dustin S
URN etd-01172011-120802
Title Influence of Sand Topdressing on Bermudagrass Thatch Decomposition
Degree Master of Science (M.S.)
Department Agronomy & Environmental Management
Advisory Committee
Advisor Name Title
Beasley, Jeffrey Committee Chair
Breitenbeck , Gary Committee Member
Strahan, Ronald Committee Member
Keywords
  • relative humidity
  • hybrid bermudagrass
  • temperature
Date of Defense 2010-12-14
Availability unrestricted
Abstract
Methods to control thatch layers in mature turfgrasses have relied on sand-topdressing and/or mechanical removal. Mechanical removal of thatch through vertical mowing and aerification is effective but disruptive to playing surfaces compared to sand topdressing. As a result, many turf managers have opted to implement sand-topdressing regiments as their primary method for reducing thatch buildup. This research was conducted to 1) determine the effect of cultivar on thatch decomposition and 2) examine the effect of sand topdressing on thatch microenvironment and decomposition. Sand topdressing treatments consisting of sterilized or non-sterilized sand applied at 0.4 cm 14 d-1 or as a single application at 1.2 cm and an untreated control to two hybrid bermudagrasses (Cynodon dactylon L.), ‘Tifway’ and ‘Celebration’ from May to September in 2008 and 2009. At the initiation of the experiment, Celebration had twice the thatch layer of ‘Tifway’. The only treatment that reduced thatch was sand applied every 14 d-1 reduced thatch 21% to 34% and 20% to 30% for ‘Tifway’ and’ Celebration’, respectively. In contrast, a single sand topdressing application led to net accumulations of 20% to 30% compared to accumulations of 29% to 38% increases in untreated plots. Sand applied more frequently resulted in higher microorganism populations and had no detrimental effect on turfgrass quality. Routine sand applications increased thatch relative humidity (RH) compared to untreated controls for both hybrid-bermudagrass cultivars. Laboratory experiments were conducted to examine the effect of temperature, 20 C and 30 C, and RH (80%, 90%, 95%, >99%) on ‘Tifway’ and ‘Celebration’ thatch decomposition. Increasing temperature and RH resulted in 189% to 397% increase in microbial degradation. Failure to provide adequate moisture reduced microbial activity and led to declines of 170% to 243% in decomposition when thatch was subjected to drying conditions. Because thatch tissue composition and response to changes in temperature and RH were similar between cultivars, newer more vigorous hybrid-bermudagrass such as ‘Celebration’ will require a frequent sand topdressing regiment in conjunction with mechanical removal for acceptable thatch control.
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