Date of Award

1996

Document Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

School of Nutrition and Food Sciences

First Advisor

Paul W. Wilson

Abstract

Common carpetgrass (Axonopus affinis Chase) is a low maintenance stoloniferous grass widely distributed throughout the southern coastal plains of the United States. This study investigated seed germination enhancement, seedhead suppression, waterlogging tolerance, winter hardiness, and maintenance practices for common carpetgrass. Pre-soaking common carpetgrass and centipedegrass (Eremochloa ophiuroides (Munro.) Hack.) seed was beneficial at the 30C germination temperature. Priming seed in KNO$\sb3$ solutions significantly accelerated seed germination of both centipedegrass and carpetgrass at 30C, and increased total germination percentage of centipedegrass. At 20 and 25C, seed priming significantly improved mean time of germination for both grass species and total germination percentage of common carpetgrass. Neither pre-soaking nor priming resulted in germination enhancement at 15C for either species. Plant growth regulators significantly reduced seedhead number, cumulative growth and clipping yield. Trinexapac-ethyl (0.48 kg$\sp{-1}$), fluazasulfuron (0.054 kg ha$\sp{-1}$) and sulfometuron (0.63 kg ha$\sp{-1}$) were effective in reducing nonmowed seedhead growth and increasing turfgrass quality. Applications of trinexapac-ethyl (0.32 and 0.48 kg ha$\sp{-1}$) significantly improved turfgrass quality and color of mowed common carpetgrass. Soil waterlogging significantly increased Fe and Mn tissue nutrient levels of carpetgrass and centipedegrass. Common carpetgrass and centipedegrass survived 6 weeks of continuous waterlogging in the summer heat. Data suggested that retention of high Fe and Mn levels within or on root tissue may have served as an adaptive mechanism. Nonstructural carbohydrate (NSC) partitioning and node survival increased during winter acclimation. Sucrose and starch were the predominate NSC in leaves, roots and stolons. An estimated Lt$\sb{50}$ range of $-$2 to $-$4C for node survival was established for common carpetgrass. As nitrogen rates increased from 0-196 kg ha$\sp{-1}$ common carpetgrass quality and mowing frequency increased within plots mowed at 3.8 and 7.6 cm. There was little or no benefit to fertilizing nonmowed common carpetgrass. The data indicated that mowing at 3.8 or 7.6 cm would provide acceptable lawn quality. Common carpetgrass is an acceptable low maintenance lawn or utility grass. Common carpetgrass geographic adaptability seems to be limited by the lack of winter hardiness.

ISBN

9780591204087

Pages

127

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