Semester of Graduation

Fall 2017

Degree

Master of Science (MS)

Department

The School of Plant, Environmental and Soil Sciences

Document Type

Thesis

Abstract

Mowing, N fertilization and the application of preemergence herbicides (PRE) are cultural practices performed on centipedegrass to improve overall turf quality. It is posited that increasing mowing height and application of fertilizers can lead to greater turfgrass rooting and increase drought survival; while the application of PRE is reported to potentially have negative impacts on rooting. At two locations in Louisiana, studies examining the effects of these practices on centipedegrass rooting and drought tolerance were conducted.

In the first 11-week study conducted, centipedegrass was treated with dithiopyr, pendimethalin, prodiamine, simazine, or indaziflam at the manufacturers’ labeled rates. During the 11-wk experiments, roots were harvested at upper and lower contiguous soil depths of 7.5 cm and analyzed for root length (RL), surface area (SA), average diameter (AD), length volume-1 (LPV), and root mass (RM). Across all treatments and soil depths, PRE did not alter rooting compared to controls with the exception of AD for simazine-treated centipedegrass at 0.397 mm compared to 0.338 and 0.341mm for prodiamine and indaziflam, respectively. At 11 wks., cores were harvested and subjected to a 28 d dry-down period. Centipedegrass maintained acceptable leaf color for 13 days before complete leaf firing occurred at 20 days. A single application of PRE to mature centipedegrass during early spring did not alter rooting or drought tolerance compared to controls.

In the second study, centipedegrass was maintained at one of four mowing heights (2.5, 5, 7.5 and 10 cm) and subjected to fertilization or no fertilization. During the 29-wk experiments, roots were harvested and analyzed as above and subjected to a mid-summer 36-day drought simulation. All centipedegrass in these experiments exhibited a pattern of increased leaf firing over the drought simulation with unfertilized centipedegrass maintaining acceptable leaf color (≥5) for 19 days at 5.9 compared to 4.8 when fertilized. Rooting parameter measurements across all mowing heights and soil depths initially declined from spring into summer then increased in fall. This, in conjunction with the lack of changes in rooting from alterations in cultural practices, indicates soil temperature may be a significant factor in centipedegrass rooting.

Date

10-26-2017

Committee Chair

Beasley, Jeffrey

DOI

10.31390/gradschool_theses.4324

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