Effects of Improved Ryegrass Cultivars On Spring Transition of Warm-Season Turfgrass Fairways.

In the southern United States, autumn overseeding of warm-season turf can lead to a difficult spring transition of cool-season turfgrasses and increased reliance upon chemical inputs.  With the release of improved annual and perennial ryegrasses, managers may be able to selectively choose the transition speed of cool-season turf and promote the recovery of the warm-season turf.  A two-year field study was conducted to investigate cultural practices to improve the performance of overseeded turfgrass systems.  The study examined morphological changes of three warm-season turfgrass species as affected by three-dimensional canopy management (3DCM) and the impact of improved turf-type annual ryegrass (Lolium multiflorum Lam.) and perennial ryegrass (Lolium perenne L.) cultivars on transition speed and warm-season turfgrass recovery.  Plots were sodded August 2006 with ‘Tifway 419’ bermudagrass [Cynodon dactylon (L.) Pers. x C. transvaalensis Burtt-Davy] ‘Cavalier’ zoysiagrass [Zoysia matrella (L.) Merr.], and ‘Sea Isle I’ seashore paspalum (Paspalum vaginatum Swartz) over a modified rootzone containing a Booneville (fine, smectitic, thermic, chromic, vertic Albaqualfs) soil amended with coarse sand having a final particle size distribution of 93.5% sand, 5.1% silt, and 1.4 % clay.  Sub-plot treatments consisted of three grooming frequencies (groomed every mowing, groomed weekly, and not groomed) and four L. multiflorum/L. perenne mixes (100/0, 50/50, 0/100, and 0/0).  All plots were mowed at fairway heights (1.3 cm).  Data collected included turf quality, thatch thickness, ryegrass coverage, spring green-up, leaf area index, biomass production, light incidence within the canopy, and weed development.  One year of data indicated grooming did not affect thatch depth, shoot density, or ryegrass coverage.  Effects of overseeding mix on turf quality and density will be discussed.  Additional data from 2008 and 2009 will be presented.