Quantifying the Influence of the Aggressiveness and Seeding Ratios of Kentucky Bluegrass on Sod Strength of Tall Fescue-Kentucky Bluegrass Seed Mixtures – Final Report


Researchers: Dr. Ross Braun and Emmanuel Nwachukwu, Kansas State University


Utilizing mixtures of tall fescue (TF) (Festuca arundinacea Shred.) and Kentucky bluegrass (KBG) (Poa pratensis L.) for sports fields, lawns, and other turfgrass areas is a common practice for turfgrass managers and sod producers in the U.S. because it can provide greater genetic diversity and improved tolerance to environmental stresses compared to a single species. Kentucky bluegrass is well known for its excellent sod strength and handling characteristics due to its rhizomatous growth habit compared to the bunch-type habit of TF; however, TF seed and sod is gaining


p Experiment 1ab Cultivar(s)


Avenger 3, Blackwatch 2, Maestro


Armada


Aggressive classificationc


100% TF blend for comparison


Shannon Low KBG Volt


Low KBG Low KBG


Bolt Medium KBG Fullback


High KBG Medium KBG


Martha Medium KBG Hampton High KBG Legend High KBG Sombrero


TF:KBG). b


KBG treatments in both experiments. c


popularity because of its superior heat and drought tolerance compared to KBG. Terefore, sod production of TF continues to increase, and more research is needed to assist sod producers growing 100 percent TF sod or TF:KBG sod mixtures.


Te Lawn Institute funded a research project starting in 2023 that included two field research experiments with the objectives to measure the influence of seeding mixture ratios and KBG growth aggressiveness on the sod strength and handling of TF-KBG mixture sod (Fig. 1). Experiment 1 research objectives were to measure the sod strength and handling of 95:5 (weight/weight) TF-KBG mixtures that included different KBG aggressiveness classification types (Table 1). Experiment 2 research objectives were to measure the sod strength and handling of different TF:KBG seeding ratios [100:0 (w/w), 97:3, 95:5, and 90:10 with different KBG aggressive types (e.g., low, medium, or high aggressive growth within each ratio) (Table 1). Both experiments were arranged in a randomized complete-block design with four replications. block design with four replications.


Table 1. Treatments in Experiment 1 and Experiment 2 at Kansas State University. p


Experiment 2b Cultivar(s)


Avenger 3, Blackwatch 2, Maestro


Armada (low)c


Fullback (medium) Legend (high) Armada Fullback Legend Armada Fullback Legend


Seeding mixture ratio (w/w, TF:KBG)


100% TF blend for comparison


97:3 97:3 97:3 95:5 95:5 95:5


90:10 90:10 90:10


a For experiment 1, aggressive KBG cultivars were included in the sod mixture seeding ratio of 95:5 (w/w, Avenger 3, Blackwatch 2, and Maestro (TF blend of 33.3% each) was included in all treatments, including Growth aggressive classification was based on communication with seed scientists/suppliers.


y


TPI Turf News September/October 2025


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