Competitiveness of Three Warm-season Turfgrasses during Spring Transition of Overseeded Turfs

Prior research on the topic of southern winter overseeding systems has been limited to the testing of management practices, seeding rates, and cool-season grass genotypes. A desirable spring transition may also be dependent on warm-season turfgrass species. A field study was conducted in College Station, TX, on overseeded (Lolium perenne L.) and nonoverseeded zoysiagrass (Zoysia spp. Willd. ‘Cavalier’), seashore paspalum (Paspalum vaginatum Swarz. ‘Sea Isle 1’), and hybrid bermudagrass [Cynodon dactylon (L.) Pers. ´ C. transvaalensis Burtt-Davy ‘Tifway’] fairway turfs. The objectives of the experiment were to measure eight canopy attributes of the warm-season species and to relate differences to competitiveness during the spring transition. Samples of canopies were collected in May, July, and September from each warm-season turfgrass. Leaf area, leaf and shoot weight, and leaf and shoot counts were measured and used to calculate common plant canopy metrics such as leaf area index, leaf area ratio, specific leaf area, and leaf weight ratio. Grasses capable of extending vertical stems as an overtopping mechanism, as conveyed by lower leaf weight ratios, appear more competitive for light in a spring overseeded turf (e.g., hybrid bermudagrass) than grasses that invest significant resources towards leaf production (e.g., zoysiagrass). High shoot plasticity (change in canopy traits due to overseeding treatment) and efficient leaf area production (i.e., high specific leaf area) of seashore paspalum also contributed a competitive advantage during the spring transition period. This research demonstrates that canopy morphology can be a contributing factor to competitiveness of warm-season turfgrasses in an overseeded turfgrass system.