Steven J. Keeley

Performance in the Transition Zone of Two Hybrid Bluegrasses Compared with Kentucky Bluegrass and Tall Fescue

Hybrid bluegrasses (HBG) are crosses between Kentucky bluegrass (Poa pratensis L.) (KBG) and Texas bluegrass (Poa arachnifera Torr.), which may exhibit better heat tolerance and drought resistance than other cool-season turfgrasses. Two HBG cultivars (‘Thermal Blue’ [HBG1] and ‘Dura Blue’ [HBG2]), one KBG (‘Apollo’), and one tall fescue (Festuca arundinacea Schreb.; ‘Dynasty’ [TF]) were evaluated for two years in northeastern Kansas for establishment rates after seeding, visual quality and growth characteristics, and drought resistance. Irrigation treatments included 60% and 100% evapotranspiration (ET) replacement and a control receiving only natural precipitation. Tall fescue reached full cover 37, 52, and >73 days faster than HBG1, KBG, and HBG2, respectively. In both years, average quality over the growing season ranked: TF > KBG > HBG1 > HBG2; an infestation of bluegrass billbugs (Sphenophorus parvulus Gyllenhal) in 2003 reduced quality among bluegrasses but not TF. Canopy density was lower in HBG2 and higher in TF among treatments. Clipping biomass of TF was 42 to 73% higher than that of the bluegrasses. Vertical growth rates were highest in HBG1 and TF and lowest in KBG. Drought generally reduced quality among bluegrasses, but effects on TF were negligible. Results indicate that TF is better adapted than HBG where soils are deep in the transition zone. Further research is needed using new cultivars of HBG and in areas with different soils.

Effect of irrigation water pH and acidifying source on silvery-thread moss (Bryum argenteum Hedw.) establishment

Abstract Many bryophytes are intolerant of osmotic stresses; nevertheless, Bryum argenteum often spreads in golf course greens irrigated with water containing a moderate amount of sodium and/or bicarbonates. The ability of B. argenteum to survive in this stressful environment could be linked to the use of acid injection systems, which are often retrofitted to irrigation systems to combat the negative effects of these harmful salts. The objective of this study was to determine if altering the pH of sodic irrigation water using either sulfuric or hydrochloric acid affects the growth of B. argenteum. Secondarily, if growth of B. argenteum was affected, we sought to understand whether that effect was due to differences in nutrient uptake or availability under the different water pHs and/or acidifying sources. Phosphate buffer solutions (0.01 M, pH  =  9) were titrated with each acid to obtain pHs 5, 6, 7 and 8. Irrigation solutions were applied daily to pots containing a sand substrate and nascent B. argenteum for 28 d. Acid source had no effect on moss cover, but pH significantly affected B. argenteum cover. Generally, pots irrigated with pHs 5 and 6 had six- to seven-fold increases in B. argenteum cover compared to pHs 7 and 8. Additionally, the shoot tissue of pots treated with pH 5 contained twice as much potassium compared to pots irrigated with pH 9. These results indicate the growth of B. argenteum increases when acid injection systems are used to amend sodic irrigation water.

Divergence in Life-History and Developmental Traits in Silvery-Thread Moss (Bryum argenteum Hedw.) Genotypes between Golf Course Putting Greens and Native Habitats

Abstract Silvery-Thread Moss (Bryum argenteum Hedw.) is an undesirable invader of golf course putting greens across North America, establishing colonies and proliferating despite practices to suppress it. The goal was to grow genotypes of green (growing in putting greens) and native (growing in habitats outside of putting greens) B. argenteum in a common garden experiment, allowing an experimental test of life-history traits between genotypes from these two habitats. Seventeen collections of green and 17 collections of native B. argenteum were cloned to single genotypes and raised through a minimum of two asexual generations in the lab. A culture of each genotype was initiated using a single detached shoot apex and was allowed to grow for 6 mo under conditions of inorganic nutrients present and absent. Compared with genotypes from native habitats, genotypes of B. argenteum from putting greens exhibited earlier shoot regeneration and shoot induction, faster protonemal extension, longer (higher) shoots, lower production of gemmae and bulbils, and greater aerial rhizoid cover, and showed similar tendencies of chlorophyll fluorescence properties and chlorophyll content. Cultures receiving no inorganic nutrients produced less chlorophyll content, greatly reduced growth, and bleaching of shoots. Mosses from putting greens establish more quickly, grow faster, produce more abundant rhizoids, and yet do not produce as many specialized asexual propagules compared with mosses of the same species from native habitats. The highly managed putting green environment has either selected for a suite of traits that allow the moss to effectively compete with grasses, or genotypic diversity is very high in this species, allowing a set of specialized genotypes to colonize the putting green from native habitats. Successful golf course weeds have been able to adapt to this highly competitive environment by selection acting on traits or genotypes to produce plants more successful in competing with golf course grasses.

Evaluating the Effects of Simulated Golf Cart Traffic on Dormant Buffalograss and Turfgrass Colorants

Percent green cover will ultimately decrease over time when traffic is applied to dormant buffalograss with turfgrass colorants. Data suggests that an additional five weeks of acceptable green cover can be achieved under high traffic situations when Endurant Premium is applied to dormant turf.

Influence of Glyphosate Timings on Conversion of Golf Course Rough from Tall Fescue to ‘Sharps Improved II’ Buffalograss

All treatments, except the control that received no glyphosate application, resulted in acceptable buffalograss establishment (>90% buffalograss green cover) by 70 days after seeding (DAS). However, any treatment not sprayed prior to seeding date or that received a 7 DAS application lagged behind in establishment for 6 weeks after seeding.

Influence of Cultivation Practice and Mowing Height on Conversion of Golf Course Rough from Tall Fescue to ‘Sharps Improved II’ Buffalograss

Slit-seeding buffalograss provided the quickest (85% cover, 8 weeks after seeding) establishment of all the cultivation practices. Mowing height had no effect on establishment success.

Effects of Home Value, Home Age, and Lot Size on Lawn Watering Practices of Residential Homeowners

Lawn care and lawn watering practices of residential homeowners were significantly affected by home value and home age, but lot size was less a factor.

Influence of Fertilizer Source and Rate on Buffalograss Divot Recovery

Application of quick-release nitrogen fertilizer increased buffalograss divot recovery. A quick-release fertilizer at 1 lb N/1,000 ft2 resulted in 50% divot recovery 6.3 days quicker compared to the untreated control.

Influence of Simulated Golf Cart Traffic and Nitrogen Rate on Buffalograss Quality

Application of 2 and 3 lb N/1,000 ft2 resulted in acceptable buffalograss quality when subjected to simulated golf cart traffic. Across all fertilizer treatments, traffic rates of 8 and 16 passes per week resulted in unacceptable quality ratings for the study duration.