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Golf ball roll is measured with a United States Golf Association (USGA) Stimpmeter. Three Stimpmeters were fabricated identically to the USGA Stimpmeter, except for the location of the ball release notch. The modified Stimpmeters had ball release notches located at 57, 38, and 19 cm, rather than at 76 cm from the beveled end. The modified Stimpmeters were tested on a creeping bentgrass green located at Mead, Neb., at three mowing heights (4.8, 4.0, and 3.2 mm). The Stimpmeters were effective in measuring golf ball roll distance and provided reasonable and consistent estimates of friction. Modified Stimpmeters are relatively inexpensive to construct and can be used on small turfgrass research plots.
Buffalograss [Buchloë dactyloides (Nutt.) Engelm.] is a warm-season perennial grass native to the North American Great Plains region and has been used as a low-maintenance turfgrass. Turf-type buffalograsses are available and are commonly used on nonirrigated land. Our objectives were to determine the deepest planting depth of burrs that would allow acceptable emergence, and to evaluate planting depth effects on buffalograss seedling morphology. Two greenhouse experiments were conducted in Fall 2000. Experimental design was a randomized complete block with 4 replications and a 3 (cultivar) × 6 (planting depth) factorial treatment arrangement. Results showed that buffalograss emergence decreased as planting depth increased. All cultivars had <10% total emergence at planting depths >50 mm. Emergence rate indices were greatest when planting depth was 13 mm and were significantly lower at planting depths of 51 and 76 mm. Average coleoptile length was 11 mm. Coleoptile length was similar between all planting depths except for the 13 mm depth which resulted in 9-mm-long coleoptile. Subcoleoptile internode length increased with planting depth up to 38 mm. Planting depths deeper than 38 mm did not significantly increase subcoleoptile internode length.
Sod heating during storage can limit the distance sod may be shipped. Two experiments were conducted to determine the effect of multiple preharvest applications of trinexapac-ethyl [4-cyclopropyl-α-hydroxy-methylene)-3,5-dioxocyclohexanecarboxylic acid methyl ester] at 0.23 kg·ha-1 (0.21 lb/acre) on kentucky bluegrass (Poa pratensis) sod temperatures during the first 24 h of storage. Experimental design was completely randomized with three replications and a 2 (trinexapac-ethyl verses control) × 3 (8-h storage intervals) factorial arrangement of treatments. Trinexapac-ethyl treatments were applied 6 and 2 weeks before harvest in the first experiment and 10, 6, and 2 weeks before harvest in the second experiment. Two and three applications of trinexapac-ethyl reduced sod storage temperatures. The reduction in rate of heating in treated sod became significantly different than untreated sod within 4 h after harvest. Mean sod temperatures in both experiments were 3 °C (6 °F) cooler in treated sod after 12 h of storage than untreated sod. These results suggest that trinexapac-ethyl could be used by sod growers to extend storage times and increase shipping and market areas. A multiple application program can enable sod growers to maximize the enhancement effects of trinexapacethyl on sod storage life.
Native wildflowers are important components of grassland communities and low-maintenance wildflower seed mixtures. Weed interference limits successful establishment of native wildflowers from seed. Experiments were conducted to determine the influence of the imidazolinone herbicides imazethapyr, imazapic, and imazaquin on the establishment of blackeyed susan (Rudbeckia hirta L.), upright prairieconeflower [Ratibida columnifera (Nutt) Woot. and Standl.], spiked liatris [Liatris spicata (L.) Willd.], blanket flower (Gaillardia aristata Pursh.), purple coneflower [Echinacea purpurea (L.) Moench.], and spotted beebalm (Monarda punctata L.). Wildflower response to the herbicide treatments was variable and appeared to be influenced by the level of weed interference. Establishment of the native wildflowers after application of imazethapyr or imazapic at 70 g·ha-1 a.i. was generally improved at sites with greater weed interference. Emergence and density of wildflowers was often reduced by imazapic in sites with low weed interference. Flower density during the second growing season was usually either improved or not reduced by either imazethapyr or imazapic. Based on these findings, imazethapyr and imazapic can reduce weed interference and improve the establishment of some native wildflowers in areas with high weed infestations. Chemical names used: (±) -2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-methyl-3-pyridinecarboxylic acid (imazapic); 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-3-quinolinecarboxylic acid (imazaquin); 2-[4,5-dihydro-4-methyl-4-(1-methylethyl)-5-oxo-1H-imidazol-2-yl]-5-ethyl-3-pyridinecarboxylic acid (imazethapyr).
Heat accumulation during storage of sod may reach lethal temperatures within 4 days, decreasing sod quality. Treatment with trinexapac-ethyl reduces heat accumulation during sod storage. However, heat tolerance of grasses treated with trinexapacethyl has not been documented. Our objectives were to: 1) determine the lethal temperatures for Kentucky bluegrass (Poa pratensis L.); and 2) identify the effect of a single application of trinexapac-ethyl on heat tolerance. Experimental design was a randomized complete block with three replications and a two (trinexapac-ethyl vs. control) × two (cultivars) factorial arrangement of treatments. Ten days after chemical treatment, Kentucky bluegrass sprigs were exposed to heat stress for 4 days in a temperature gradient block under low vapor pressure deficit. Treatment with trinexapac-ethyl at 0.23 kg·ha-1 reduced heat tolerance. Temperature needed to kill 50% of the population was 35.5 °C for treated vs. 36.1 °C for nontreated grass. Trinexapac-ethyl is in the same chemical family as the cyclohexanedione herbicides that interfere with lipid syntheses in grasses. This may be a reason for the slight decrease in heat tolerance. The practical value of trinexapac-ethyl treatment in reducing heat accumulation during storage of sod may be partially negated by a decrease in heat tolerance. Chemical name used: [(4-cyclopropyl-α-hydroxy-methylene)-3,5-dioxocyclohexanecarboxylic acid methyl ester] (trinexapac-ethyl).
Internal heating during sod storage can lead to plant deterioration and is a limiting factor in sod transportation. Storage practices such as the use of refrigeration and vacuum packaging have increased storage time; however, these are usually not practical or economical. Experiments were conducted to develop a feasible growth regulator management technique, using trinexapac-ethyl, to increase the storage life of Kentucky bluegrass (Poa pratensis L.) sod. Experimental setup for all experiments was a completely randomized design with a 2 (trinexapac-ethyl vs. control) × 3 (storage times) factorial treatment arrangement with 3 replications. Trinexapac-ethyl was applied at 0.23 kg·ha-1 to Kentucky bluegrass 2 weeks prior to harvesting. Results showed that sod treated with trinexapac-ethyl was as much as 10 °C cooler than the controls in the center of the sod stacks after 48 hours of storage. The reduced sod temperatures led to a 30% greater tensile strength and 17% better quality ratings in treated sod after 24 hours of storage. A preharvest application of trinexapac-ethyl appears to increase storage times of Kentucky bluegrass sod, which may improve sod market quality. Chemical name used: [4(cyclopropyl-α-hydroxy-methylene)-3,5-dioxocyclohexanecarboxylic acid ethyl ester] (trinexapac-ethyl).
Field studies were conducted in Kansas, Nebraska, and Oklahoma in 1996 to evaluate the influence of nitrogen (N), phosphorus (P), and potassium (K) applied alone or in combination on the establishment rate of buffalograss [Buchloe dactyloides (Nutt.) Engelm.] from seed. `Cody' buffalograss burrs were planted at 98 kg·ha-1. Nitrogen was applied at 0 or 49 kg·ha-1 at planting and at 49 kg·ha-1 weekly or every other week for 5 weeks after seeding (WAS). The total N amounts applied were 0, 49, 147, or 294 kg·ha-1. Phosphorus and K were applied at rates of 0 or 49 kg·ha-1 at planting only. Percent buffalograss coverage ratings were taken weekly for up to 11 WAS. Buffalograss coverage was enhanced by N rates up to 147 kg·ha-1. Application of P improved buffalograss establishment at the Nebraska and Oklahoma sites but had no effect at the Kansas site. Potassium application had no influence on establishment at any site. Chemical names used: methyl 2-[[[[(4-methoxy-6-methyl-1,3,5-triazin-2-yl)-amino]carbonyl]amino] sulfonyl]benzoate (metsulfuron methyl); 6-chloro-N,Ń-diethyl-1,3,5-triazine-2,4-diamine (simazine)
Field studies were conducted at two sites in Nebraska (NE1 and NE2) and one site in Kansas (KS) in 1994 to determine the influence of selected preemergence herbicides on establishment of seeded `Sharp's Improved' buffalograss [Buchloe dactyloides (Nutt.) Engelm.]. Herbicides were applied within 2 days after seeding. Application of imazethapyr at 0.07 kg·ha-1 usually resulted in buffalograss seedling density, vigor, and foliar cover that were superior to buffalograss stands where other herbicides were applied. Buffalograss response to AC 263,222 at 0.07 kg·ha-1 was variable and appeared to be influenced by level of weed interference. Seedling density and vigor of buffalograss on areas treated with AC 263,222 were the same or less than on nontreated areas at KS and NE2, where weed infestations were low and moderate [5% and 45% weed foliar cover 12 weeks after treatment (WAT) on nontreated areas]. In contrast, buffalograss establishment was similar in AC 263,222- and imazethapyr-treated plots at NE1 where the weed infestation was high (>70% weed foliar cover 12 WAT on nontreated areas). At 12 WAT, weed foliar cover was <25 % at NE1 and <1 % at NE2 where imazethapyr and AC 263,222 were applied. Of all herbicides evaluated, imazethapyr at 0.07 kg·ha-1 was superior for suppressing annual grass and broadleaf weeds with no observable deleterious effects on buffalograss establishment from seed. Chemical names used: ±2-[4,5-dihydro-4-methyl-4-(l-methylethyl)-5-oxo-lH-imidazol-2-yl]-5-methyl-pyridine carboxylic acid (AC 263,222); 2-[4,5-dihydro-4-methyl-4-(l-methylethyl)-5-oxo-lH-imidazol-2-yl]-5-ethyl-3-pyridinecarboxylic acid (imazethapyr); 6-chloro-N,N′-diethyl-l,3,5-triazine-2,4-diamine (simazine).
Roughstalk bluegrass (Poa trivialis L.) is a troublesome weed on golf courses, home lawns, and athletic fields from the Midwest to the mid-Atlantic states. Bispyribac-sodium and sulfosulfuron have recently been labeled for roughstalk bluegrass control, but their use needs to be refined. Our objective was to determine the most effective herbicide strategies for control of roughstalk bluegrass. Initial studies were conducted during 2005 in Illinois and Indiana and follow-up studies in 2006 in Indiana, Illinois, South Dakota (partial shade and full sun), and Wisconsin. Applications starting in the warmer temperatures of late May and June 2005 were more effective than those starting in mid-May. Bispyribac-sodium (a.i.) was applied at 74 or 114 g·ha−1 four times at 2-week intervals decreased roughstalk bluegrass cover to 1% and 0% 12 weeks after initial treatment (WAIT) in Illinois and Indiana in 2005, respectively, whereas sulfosulfuron (a.i.) at 13 or 27 g·ha−1 applied twice at 2-week intervals decreased cover to no less than 18%. In 2006, bispyribac-sodium was most effective in Indiana and Illinois decreasing cover to as low as 4%, whereas sulfosulfuron was most effective in South Dakota resulting in a decrease in cover to as low as 7%, and both herbicides performed similarly in Wisconsin. Three applications of sulfosulfuron (a.i.) at 27 g·ha−1 at 2-week intervals or four applications of bispyribac-sodium (a.i.) at 56 or 74 g·ha−1 at 2-week intervals were most effective for roughstalk bluegrass control.
Attempts to establish buffalograss [Buchloë dactyloides (Nutt.) Engelm.] turfs from sprigs have been limited and successful stand establishment has been inconsistent. This study was conducted to determine whether accumulated growing degree-days (GDD) and cultivar of harvested sprigs have an effect on buffalograss sprig establishment. Two field studies were conducted on a Tomek silty-clay loam (fine smectitic mesic Pachic Agriudolls) in 2007 and again in 2008. The cultivars Legacy, a hexaploid, and Prestige, a tetraploid, were used in this investigation. Sprigs were harvested and planted on 29 June, 17 July, 31 July, and 15 Aug. in 2007 and 15 May, 4 June, 19 June, 2 July, 21 July, 31 July, and 18 Aug. in 2008. The GDDs were back-calculated from these harvest dates. The harvest date of the sprigs represented 1050, 1380, 1670, and 1980 GDD in 2007 and 120, 380, 620, 840, 1200, 1400, and 1720 in 2008. Aboveground buffalograss phytomass and percent buffalograss groundcover data were collected in 2007 and 2008. In 2008, total available sugar and starch content of harvested sprigs were determined for each sprig harvest date. In the 2007 studies, sprigs harvested at 1050 GDDs resulted in the best establishment for both cultivars. In the 2008 studies, ‘Legacy’ established successfully through 840 GDDs, and ‘Prestige’ established through 1200 GDDs. Sugar or starch content did not appear to influence sprigging success. These results support the recommendation to establish buffalograss from sprigs harvested before 1050 GDDs for best results.