Date of Award

8-2012

Document Type

Thesis

Degree Name

Master of Science (MS)

Legacy Department

Plant and Environmental Science

Advisor

McCarty, Dr. Lambert B

Committee Member

Quisenberry , Dr. Virgil

Committee Member

Bridges , Dr. William

Abstract

Four field studies, one laboratory and one greenhouse study were conducted from April 2011 through August 2011 at Clemson University in Clemson, SC on `L-93'creeping bentgrass (Agrostis stolonifera L.), `Tifeagle' bermudagrass (Cynodon dactylon (L.) Pers. X C. transvaalensis Burtt-Davy), and a combination of `Tifway' (Cynodon dactylon (L.) Pers. X C. transvaalensis Burtt-Davy) and common bermudagrass (Cynodon dactylon (L.)
The objectives of this research were: (i) evaluate bentgrass response to two irrigation regimes, light and frequent irrigation (replacing daily ET), verses deep and infrequent irrigation (watering at the sign of wilt); (ii) evaluate the combination of a humectant and a soil wetting agent under these two irrigation regimes; (iii) evaluate the efficacy of a humectant, various wetting agents and a fungicide on bermudagrass infected with fairy ring (Lycopedon spp.); (iv) evaluate a humectant and various wetting agents on localized dry spots (LDS) on a `TifEagle' bermudagrass putting green; (v) evaluate a humectant and various wetting agents on non-irrigated common and `Tifway' bermudagrass blend in a sports field; (vi) assess the changes in volumetric water content (VWC) of a soil treated with different water sources, a humectant and a wetting agent; and (vii) assess the fluctuations of volumetric water content over a 7 day period under two relative humidity levels.
The humectant, Hydretain ES Plus; two wetting agents, Cascade Plus and Primer Select; and Primer Select + the commercial fungicide, Prostar (flutolanil), were used during these studies. All field treatments were applied according to the label rate and plots were irrigated prior to application at 2.54 mm (0.10 inches) and following application at 6.35 mm (0.25 inches) to provide uniform soil moisture, except for the non-irrigated study.
All treatments provided a normal electrical conductivity (EC) of 0.01 dS/m for the bentgrass irrigation regimes. Also, the light and frequent irrigation (LF) plots had the highest EC while the dielectric constant increased by 6v (volts) throughout each study. Turf quality and turf color provided acceptable visual quality and color of ≥7, but did not differ from the control. Phytotoxicity provided a rating of >40% and suggests there was significant chemical burn. At 14 DAT, Cascade held the most moisture in the upper 0-5.7 cm rootzone at 30%. Cascade provided a 20% increase on the upper rootzone moisture verses the other treatments. Soil temperatures were maintained around 35¡C for all studies on the bentgrass. All root diameter measurements provided a slight decrease from the beginning to the end from approximately 0.22 to 0.19 cm. Root length increased from 397 cm to 591 from the first sampling to 35 DAT, respectively. However, root length decreased from 35 to 42 DAT from 591 cm to 444 cm, respectively, Root volume also provided a similar trend decreasing after 35 DAT.
Localized dry spot and fairy ring treatments provided a wettable (water penetrating the soil in <5 >seconds) to slightly wettable soil and all treatments, including the check plots passed the water droplet penetration test (WDPT) for hydrophobicity. The non- irrigated study provided no differences among treatments or treatment ratings.
However, Cascade provided the highest volumetric water content in the non-irrigated field study. Cascade also provided the highest volumetric water content in the greenhouse and laboratory studies with < 20% (20 g/cm-3).

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