Compatibility of species mixtures may be advantageous because of genetic diversity and improved tolerance of pests and environmental stress. However, mixtures must be balanced and dominance of one species over another will negate the intent of the mixture.
In past years, it was not possible to mix tall fescue and Kentucky bluegrass because the fescue tended to segregate into patches in the established mixture. However, development of newer, more aggressive "turf type" tall fescues increased the probability that balanced mixtures could be attained.
The long term objective of our three projects, beginning in 1985, is to determine the practicality of maintaining turf type tall fescue in mixture with Kentucky bluegrass and perennial ryegrass under varied management conditions.
1985 to 1989: Compatibility of Kentucky bluegrass and perennial ryegrass with tall fescue in mixtures
The objective of this study was to determine if compatible mixtures of tall fescue, Kentucky bluegrass, and perennial ryegrass could be maintained at close mowing heights and under three nitrogen regimes. This research was the basis for Dr. K.L. Hunts Ph.D. thesis dissertation.
Plots of a tall fescue blend (Brookston, Falcon, Mustang, Olympic, and Rebel), Kentucky bluegrass blend (Baron, Enmundi, and Ram I) and a perennial ryegrass blend (Citation II, Fiesta, Palmer, and Prelude) were seeded in late August, 1984. Mixtures of the three species blends were also seeded with tall fescue comprising 80% by weight of the mixtures. Turf was irrigated only during the establishment period.
Management treatments included 5/8 and 7/8-inch mowing heights and seasonal totals of 1.5 lb and 3.0 lb N per 1000 sq ft applied in fall or 3.5 lb N spring and fall applied. Botanical composition was measured annually in June 1985 to 1989 with an optical point quadrat.
In the tall fescue-perennial ryegrass mixture, tall fescue lacked competitiveness and decreased from 51% the first year to 11% of the plant population five years after planting. Tall fescue declined from 42% the first year to only 9% of the tall fescue-Kentucky bluegrass-perennial ryegrass mixture after five years. In the tall fescue-Kentucky bluegrass mixture, tall fescue had an initial one-year decline from 60 to 42% then remained competitive with Kentucky bluegrass and at five years comprised 44% of the turf compared with 47% Kentucky bluegrass.
The tall fescue-Kentucky bluegrass mixture and the tall fescue blend generally received higher quality ratings compared to the tall fescue-perennial ryegrass and the tall fescue-Kentucky bluegrass-perennial ryegrass mixtures starting in August 1988 and through completion of the study. Nitrogen and cutting height had little effect on botanical composition and had only occasional, minor effects on turfgrass quality.
The bottom line: Results of this first study showed that selected, blended tall fescue cultivars under nonirrigated conditions can adapt to close mowing and remain competitive in mixture with selected, blended Kentucky bluegrass cultivars over several years. Under these same conditions, perennial ryegrass dominated both species in mixtures.
1990-1995 Management effects on tall fescue, Kentucky bluegrass, and perennial ryegrass in mixtures
The objective of this study was to determine the influence of several management factors on tall fescue, Kentucky bluegrass, and perennial ryegrass growing in mixtures.
Plots of a three cultivar tall fescue blend (Rebel, Arid, and Mustang), a two cultivar "dwarf" tall fescue blend (Shortstop and Trailblazer), a three cultivar Kentucky bluegrass blend (Baron, America and Merit), and a three cultivar perennial ryegrass blend (Palmer, Manhattan II and Derby) were seeded in September 1989. Tall fescue in seed mixtures with the other two species was at least 80% by weight. The study was duplicated on adjacent parcels of land. One parcel was irrigated and the other was not irrigated. Fertilization followed guidelines for cool season turf with approximately 75% of seasonal N applied late August to late November.
After five years, mixtures averaged over the irrigated and nonirrigated locations were approximately 62% "turf type" tall fescue vs. 35% Kentucky bluegrass and 48% "dwarf" tall fescue vs. 44% Kentucky bluegrass. Kentucky bluegrass was more competitive in the irrigated location than the nonirrigated location. Mowing at 3/4 inch compared with 2 inches and simulated traffic imposed on mixtures one year before counts were initiated had little effect on populations. Perennial ryegrass dominated mixtures regardless of management. Disease incidence was a principal influence on turfgrass quality and the advantage of mixing species for disease resistance was apparent.
The bottom line: These results show that selected, blended tall fescue cultivars may be competitive in mixture with selected, blended Kentucky bluegrass cultivars under varied management conditions including irrigation or no irrigation, close mowing, and brief but intense traffic. The study also confirmed our earlier observations that perennial ryegrass will dominate in mixtures with tall fescue and Kentucky bluegrass.
1995 to present: Compatibility of tall fescue and Kentucky bluegrass in mixtures as influenced by Kentucky bluegrass blend and seeding rate.
The objective of this study is to determine the influence of Kentucky bluegrass blend composition and seeding rate on the competitiveness of tall fescue in mixture with Kentucky bluegrass.
Three Kentucky bluegrass blends (coarse textured cultivars; aggressive cultivars; warm weather adapted cultivars) and a tall fescue blend (Houndog V, Jaquar III, Falcon II, SR 8210, Rebel III, and Mustang II) were seeded in September, 1996. Mixtures of each of the three Kentucky bluegrass blends with the tall fescue blend were also seeded with tall fescue comprising 20%, 50%, or 90% of each seed mixture by seed weight for a total of nine mixture combinations.
The test was planted in two adjacent locations. One location is irrigated and the other is not irrigated. Turf is mowed at 2 inches as needed and receives 3 to 4 lb N per 1000 sq ft per year with most of the fertilizer applied in the fall.
Early Results: Percentages of tall fescue and Kentucky bluegrass are consistent with seeding rates at one year after seeding in the irrigated location. For example, tall fescue comprised 71% of the turf stand where the seeding mixture was 90% tall fescue by weight, 48% of the stand seeded with 50% tall fescue, and 19% of the stand seeded with 20% tall fescue. Cultivar composition of the three Kentucky bluegrass blends seeded with tall fescue had no effect on percent species of the established turf.
In the nonirrigated location the effect of seeding rate on turf composition was similar to that of the irrigated location. However, in the nonirrigated location the cultivar composition of the three Kentucky bluegrass blends also had a significant effect on the turf composition. For example, tall fescue at 90% of the seeding mixture with Kentucky bluegrass blend "A" comprised 79% of the established turf but only 62% of the turf when the fescue mixture was seeded with bluegrass blend "C".
While this early information is interesting, population data will be more meaningful at 4 to 5 years after seeding when mixtures have stabilized.
See other papers in this year's report
Posted July 10, 1998