International Turfgrass Society Research Journal最新文献

This research aimed to determine if creeping bentgrass (Agrostis stolonifera L.) can be used as an alternative to colonial bentgrass (Agrostis capillaris L.) in a mixture with red fescue [equal rates of Chewings fescue (Festuca rubra ssp. commutata Gaud.) and slender creeping red fescue (Festuca rubra ssp. littoralis [G. Mey.] Auquier)] on Nordic golf greens managed without pesticides. The two mixtures were compared in two experiments: Experiment 1 under the creeping bentgrass management regime (mowing height, 3 mm; fertilization, 15 g N m⁻² yr⁻¹) and Experiment 2 under the red fescue management regime (5 mm and 10 g N m⁻² yr⁻¹) at three sites during 2015–2018. A seed mixture of red fescue and velvet bentgrass (Agrostis canina L.) was included in Experiment 2 only. The results showed that red fescue plus creeping bentgrass produced greens of equal turfgrass quality and with less Microdochium patch than red fescue plus colonial bentgrass under both regimes. In Experiment 2, red fescue plus velvet bentgrass resulted in higher turfgrass quality than the other mixtures but was more susceptible to Microdochium patch than red fescue plus creeping bentgrass. Tiller counts in the mixed plots at Landvik showed that red fescue was not outcompeted by bentgrass in any of the mixtures and that it was easier to manipulate the balance between red fescue and bentgrass in the mixture with creeping bentgrass than that with colonial bentgrass. More research should be put into optimal management, especially irrigation and thatch control, of mixed red fescue–bentgrass greens.

Gaeumannomyces graminis var. graminis (Sacc.) Arx & Oliver was described as a pathogen of bermudagrass decline [takeall root rot (TARR)]; however, recent studies have reported that multiple ectotrophic root-infecting (ERI) fungi are associated with root rot in ultradwarf hybrid bermudagrass (UDHB) [Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt Davy] putting greens. This study surveyed UDHB roots from a healthy and a TARR-symptomatic green. Real-time polymerase chain reaction multiplex assays facilitated the rapid identification and quantification of four ERI fungi: G. graminis, G. nanograminis P.L Vines & M. Tom.-Pet., Magnaporthiopsis cynodontis P.L Vines & M. Tom.-Pet., and Candidacolonium cynodontis P.L Vines & M. Tom.-Pet. Gaeumannomyces nanograminis was identified more frequently than G. graminis in roots from the healthy green and had the greatest inoculum density in 2018. In contrast, G. graminis was identified in 80% more root samples than G. nanograminis in the TARR-symptomatic green in 2017, and the inoculum density of G. graminis was >2 M DNA copies per 2-µl DNA sample. Magnaporthiopsis cynodontis was the predominant fungus in both greens throughout the study; however, its inoculum density was the lowest among all four ERI fungi. Two or more ERI fungi were frequently identified as co-colonizing UDHB roots. This study showed that multiple ERI pathogens were widely distributed throughout the roots of two UDHB greens regardless of symptom expression and confirmed that ERI complexes co-colonize UDHB roots. This is the first study documenting the widespread occurrence and inoculum density levels of multiple ERI fungi colonizing UDHB roots.

The use of covers may improve the establishment of seeded turfgrass but their use in combination with drip irrigation techniques has not been evaluated. In this study, repeated twice in the spring of 2020 near Manhattan, KS, we investigated the effects of two cover types and three irrigation methods on the establishment of seeded tall fescue turfgrass [Schedonorus arundinaceus (Schreb.) Dumort.]. Turfgrass cover types included (a) polyester mesh, (b) a straw blanket, and (c) no cover as a control. Irrigation treatments were (a) subsurface drip irrigation, (b) aboveground drip irrigation, and (c) overhead sprinkler irrigation (control). Measurements of green cover, ground and drone-based normalized difference vegetation indices, and visual turfgrass quality ratings indicated that establishment was improved with both cover types compared with uncovered plots, in the order polyester > straw > uncovered in both trials, but polyester and straw became similar over time. The soil surface temperature averaged higher in polyester (14 °C) than in straw (9.5 °C) and uncovered (8.6 °C) plots during the first 12 d after seeding when the covers were installed. The results indicate that covers improved the spring establishment of seeded, cool-season turfgrass in a fine-textured soil and in a U.S. transition zone climate by mitigating low temperature extremes and reducing erosion during rainfall. Establishment was similar between drip (subsurface and aboveground) and sprinkler-irrigated treatments, but the use of protective covers is recommended when establishing turfgrass from seed.

Many cities in the United States collect and compost yard waste but need more effective and efficient ways to utilize the finished product. Home lawns represent a sizeable area that could benefit from land application of yard waste compost, but little research has been conducted regarding topdressing lawns with compost. The objectives of this study were to compare the impact of topdressing yard waste compost relative to organic and inorganic fertilizers in a mature, predominantly Kentucky bluegrass (Poa pratensis L.) lawn in Wisconsin. Three different composts (two from yard waste and one from food waste), two organic fertilizers, and a compost–compost tea combination were compared against a traditional synthetic fertilization program and a nontreated control. Treatments receiving compost (1.3 cm depth per year, in two equally sized applications) maintained acceptable turf quality over the 3.5-yr study period and resulted in significant improvements in several important physical properties of the soil. Fertilizers were also able to maintain acceptable turfgrass quality but had no impact on the physical properties of soil over the study period relative to the control. Organic and synthetic fertilizers reduced weed populations compared with the control, though the compost treatments did not. Compost and one of the organic fertilizers significantly increased the levels of soil test P but did not reach levels of environmental concern.

A study was conducted in northern Colorado to evaluate the effectiveness of two compost products on the improvement of turfgrass color and quality, necrotic ringspot (NRS) disease suppression, and thatch reduction. Two Kentucky bluegrass (Poa pratensis L.) home lawns with a history of NRS were chosen for the study. Treatments were applied twice during the 2018 growing season after all plots were aerated and consisted of (a) inoculated compost topdressing at a rate of 66 m³ ha^–1, (b) dairy manure compost topdressing at a rate of 66 m³ ha^–1, (c) urea fertilizer at 49 kg N ha^–1, and (d) a control (aeration only with no fertilizer or compost applied). Data were collected every 2 wk from May to October in 2018, and included the percentage of disease-affected turf, and turfgrass color and quality. Thatch depth was measured monthly. The inoculated and conventional compost plots had less disease than the control, and the inoculated compost showed significant disease suppression earlier than conventional compost. Season-long averages showed that the plots treated with either of the compost products had better color and turf quality than the control. When data were pooled over the course of the growing season, there were no significant differences between the two compost treatments with regard to NRS disease severity or quality. Thatch depth in plots that received inoculated compost was 17% less than in plots that received conventional compost and fertilizer. This study demonstrated that compost decreased NRS incidence and improved turf color and quality.