http://hdl.handle.net/2097/1145 Search the Channel search http://krex.ksu.edu/dspace/simple-search http://hdl.handle.net/2097/2073 Title: Mowing and drought effects on a hybrid bluegrass compared with a Kentucky bluegrass<br/><br/>Authors: Su, Kemin; Bremer, Dale J.; Keeley, Steven J.; Fry, Jack D.<br/><br/>Abstract: Hybrid bluegrasses (HBG) resemble Kentucky bluegrass (Poa pratensis L.)(KBG) but HBG may have greater heat and drought tolerance. Little is known about the performance of HBG under low mowing heights and during drought. A two-year field study was conducted near Manhattan, Kansas, USA to investigate effects of mowing and drought on visual quality and gross canopy photosynthesis (Pg) in a KBG (‘Apollo’) and HBG (‘Thermal Blue’). Treatments included three main factors at two levels each: 1) species (Apollo, Thermal Blue); 2) mowing height (7.6 cm or 3.8 cm); and 3) irrigation (100% [well watered] and 60% [drought] evapotranspiration [ET] replacement). Visual quality in Thermal Blue was similar to or lower than Apollo during both years. Visual quality and Pg declined at the lower mowing height in both species in 2004 and in Thermal Blue in 2005, but visual quality in Apollo improved slightly in 2005 including under drought. At the lower mowing height, visual quality in Thermal Blue was nine to 15% lower than Apollo in 2005, perhaps because KBG had greater leaf area and extracted more soil moisture than Thermal Blue. When well watered, Pg was lower in Thermal Blue than in Apollo but differences converged as drought progressed. Drought reduced visual quality of both grasses during both years. Data suggest that Apollo may be better suited than Thermal Blue as a turfgrass selection for the transition zone. Further research is needed to identify new cultivars of HBG that may perform better than KBG at low mowing and during drought. Wed, 04 Nov 2009 15:10:44 GMT http://hdl.handle.net/2097/2072 Title: Establishment rate and lateral spread of Festuca arundinacea cultivars<br/><br/>Authors: St. John, Rodney; Fry, Jack; Bremer, Dale; Keeley, Steve<br/><br/>Abstract: Tall fescue (Festuca arundinacea Shreb.) is usually classified as a bunch grass, but produces short rhizomes. Newer tall fescue cultivars have been developed that reportedly produce longer and more numerous rhizomes. This study was conducted to evaluate the establishment rate and lateral spread of ‘Grande II’ and ‘Regiment II’, cultivars with greater rhizome forming capability according to breeders; Water Saver RTF tall fescue blend (RTF blend), which contains the rhizomatous tall fescue ‘Labarinth’; ‘Barlexus’ tall fescue, a non-rhizomatous turf-type cultivar; ‘Kentucky-31’ tall fescue, a non-rhizomatous cultivar originally developed for forage; and SR2284 Kentucky bluegrass (Poa pratensis L.). By six weeks after seeding at Manhattan, KS, USA, Kentucky-31 tall fescue plots had the greatest coverage (80%) and Kentucky bluegrass had the least (60%). Ten months after seeding, plugs were removed from plots and transplanted into bare soil in Manhattan and Olathe, KS. Twenty-one months after transplanting, Kentucky bluegrass plugs had grown to a diameter over twice the size of tall fescue cultivars at Olathe and three times the diameter in Manhattan. Voids were created by cutting a 30.5-cm wide by 10.2-cm deep section sod from the center of each plot, filled with the same field soil, and monitored for encroachment from plants on the perimeter of the void. Void diameters 21 months after creation were 1.0 cm for Kentucky bluegrass and >18 cm for all tall fescue cultivars and the blend, none of which differed in void size. Use of rhizomatous tall fescue cultivars, or a blend containing one such cultivar, did not increase establishment rate or lateral spread relative to tall fescue cultivars not marketed as rhizomatous cultivars. Wed, 04 Nov 2009 15:09:57 GMT http://hdl.handle.net/2097/2071 Title: Establishment of seeded zoysiagrass in a perennial ryegrass sward: effects of soil-surface irradiance and temperature<br/><br/>Authors: Zuk, Alan J.; Bremer, Dale J.; Fry, Jack D.<br/><br/>Abstract: Conversion from perennial ryegrass (Lolium perenne L.) to zoysiagrass (Zoysia japonica Steud.) in the transition zone of the USA may reduce irrigation and fungicide requirements. However, environmental conditions under perennial ryegrass canopies may inhibit establishment of seeded zoysiagrass. Our objectives were to quantify solar irradiance and temperatures at the soil surface and determine their effects on establishment of ‘Zenith’ zoysiagrass seeded into existing perennial ryegrass canopies. A 31-day shade study was conducted during 2002 near Manhattan, Kansas, USA. Zoysiagrass was seeded into bare-soil plots, each covered with shade cloth that blocked 40%, 65%, or 85% of solar irradiance. Additionally, two separate experiments were conducted in 1999-2000 (Study I) and 2002 (Study II) in which perennial ryegrass canopies were maintained at: 1) 1.4 cm (untreated); 2) 0.6 cm (scalped); or 3) treated with glyphosate (N-phosphonomethyl glycine [glyphosate-treated]). Irradiance below the canopy was modeled in both experiments and seedbed temperatures were measured with thermocouples in Study II. In the shade study, zoysiagrass seedling emergence and growth decreased as shade increased in bare-soil plots (r = -0.59 to 0.69). In perennial ryegrass, scalped and untreated turf shaded the seedbed surfaces by 36% and 72%, respectively, and soil temperatures averaged 1.1oC cooler compared to glyphosate-treated turf. In scalped and glyphosate-treated plots, zoysiagrass seedling emergence was 90% greater the first year and coverage 59% greater the second year compared to untreated perennial ryegrass. Higher light penetration and seedbed temperatures during the initial 5 to 7 weeks after seeding contributed to higher zoysiagrass establishment in scalped and glyphosate-treated plots. Wed, 04 Nov 2009 15:08:56 GMT http://hdl.handle.net/2097/1301 Title: Rooting characteristics and responses of photosynthesis to irrigation deficit of two hybrid bluegrasses, Kentucky bluegrass, and tall fescue<br/><br/>Authors: Su, Kemin; Bremer, Dale J.; Keeley, Steven J.; Fry, Jack D.<br/><br/>Abstract: Drought stress is common among cool-season turfgrasses during summer in the U.S. transition zone. A two-year field study was conducted near Manhattan, Kansas, USA, to evaluate rooting characteristics and effects of drought on canopy physiology and appearance of ‘Apollo’ Kentucky bluegrass (Poa pratensis L.) (KBG), ‘Dynasty’ tall fescue (Festuca arundincea Schreb.) (TF), and two hybrid bluegrasses (HBG) ‘Reveille’ and ‘Thermal Blue’; HBG are genetic crosses between native Texas bluegrass (Poa arachnifera Torr.) and KBG. Rooting characteristics were measured in the field and greenhouse under well-watered conditions to evaluate root contributions to drought avoidance. Two irrigation treatments in the field included: 1) 60% (water-deficit); and 2) 100% (well-watered) evapotranspiration (ET) replacement. Ninety to 96% of all root length (0-80 cm) in the field and 74 to 80% of all root length (0-120 cm) in the greenhouse were in the upper 30 cm among Thermal Blue, Reveille, and KBG while in TF, only 86% and 70% of all root length in the field and greenhouse, respectively, were in the top 30 cm. In the field, tall fescue had 3 to 12 times greater root length in the lower profile (60-80 cm) among turfgrasses. Visual quality and gross photosynthesis (P[subscript]g) were greatest in TF among turfgrasses in both irrigation treatments. Reveille used more water from the 0-50 cm profile and performed better than Thermal Blue during water-deficit, but both HBG recovered from water-deficit slightly faster than KBG. Performances in visual quality and Pg generally ranked: TF > Reveille ≥ Thermal Blue = KBG. Mon, 23 Mar 2009 16:07:04 GMT