International Turfgrass Society Research Journal最新文献

Sustainable phosphorus use is essential in golf course management to prevent eutrophication and overconsumption. The study aimed to investigate if phosphorus fertilization can be reduced without negative effects on turf quality. We compared two P fertilization recommendations based on soil analyses, one based on the annual nitrogen rate, and a zero-P control. The recommendations were the “minimum level of sustainable nutrition” (MLSN), which aims to keep treatment soil levels above 18 mg P kg^–1 dry soil (Mehlich-3); the “sufficiency level of available nutrition” (SLAN), in which the threshold for excluding P fertilization is >54 mg P kg^–1 dry soil (Mehlich-3); and “Scandinavian precision fertilization” (SPF), which recommends applying P at 12% of the annual N rate. The treatments were compared via monthly assessments of turf quality and the coverage of sown species and annual bluegrass (Poa annua L.) from 2017 to 2020 on five golf courses from Germany, Sweden, China, Norway, and the Netherlands. MLSN and SPF significantly reduced soil P at all sites compared with SLAN recommendations. Turf quality showed no significant differences. The results from the mixed creeping bentgrass (Agrostis stolonifera L.)–annual bluegrass green showed a 2 to 4% increase in annual bluegrass coverage with P fertilization over the zero-P treatments. The MLSN guideline is recommended for sustainable P fertilization on established greens with low P sorption capacity under diverse climatic and management conditions. The SPF may result in application of excess P to soils with high Mehlich-3 values, as soil analyses are not considered.

Chemical control options for dallisgrass (Paspalum dilatatum Poir.) are limited, inconsistent, and damaging to desirable species. Dallisgrass and hybrid bermudagrass [Cynodon dactylon (L.) Pers. × Cynodon transvaalensis Burtt Davy] may enter dormancy at different times, allowing for safe, efficacious use of nonselective herbicides for dallisgrass control. Field experiments evaluated dallisgrass and hybrid bermudagrass dormancy by measuring plant respiration in fall and subjecting the carbon efflux data to a nonlinear exponential decay regression model fitted against cooling degree-days (CDDs). Total plant respiration differed between the species at trial initiation. Dallisgrass exhibited higher net respiration, indicating that each species proceeded into dormancy at different rates. A postemergence dallisgrass control trial was initiated at 5 to 125 CDD_22C to evaluate potential rates of quinclorac (1.5, 2.3, and 3.0 kg acid equivalent ha^–1), monosodium methanearsonate (6.1, 9.1, and 12.1 kg a.i. ha^–1), glyphosate (5, 7.6, and 10.1 kg a.i. ha^–1), and thiencarbazone + foramsulfuron + halosulfuron (0.14, 0.18, and 0.22 .kg a.i. ha^–1). Dallisgrass control 36 wk after the initial treatment was greatest with glyphosate (≥97%). Minimal bermudagrass survival was observed next spring in response to fall glyphosate. Total plant respiration per sample area differed between species at trial initiation. However, dallisgrass exhibited greater net respiration, indicating differences in behavior concerning the initiation and procession of dormancy between dallisgrass and bermudagrass. Microclimates such as shaded or low-lying areas may yield different results. Further research should determine the significance of this phenomenon to use nonselective herbicides to control dallisgrass in bermudagrass.

The rootzones of athletic fields are often built of sand for the benefit of improved drainage. Sand-based rootzones often have stability issues if the turfgrass is not fully established. The use of inorganic fibers to stabilize rootzone may create disposal and environmental issues. Previous work showed that undecomposed organic fibers such as wheat (Triticum aestivum L.) straw could stabilize sand rootzones without causing negative effect and organic matter (OM) buildup. The primary objective of this study was to evaluate the physical properties of sand rootzones modified with 1% (w/w) peat, wheat straw, coconut (Cocos nucifera L.) coir, and recycled cotton (Gossypium hirsutum L) fiber, and 2% peat. The study was conducted in field plots during 2017 and 2018. The results showed that OM content in all treatments with 1% organic fiber was comparable with that amended with 1% peat. Coconut coir and wheat straw at 1% showed similar soil moisture, water infiltration, turfgrass shoot density, and ball bounce to the values in the 1% peat treatment. The sand rootzone modified with 1% recycled cotton had lower shoot density and soil moisture than the other treatments, despite its higher infiltration rate. All rootzones modified with 1% organic fiber showed accelerated water infiltration during the 6-mo period following rootzone construction and Kentucky bluegrass (Poa pratensis L.) establishment. In conclusion, wheat straw presented physical properties similar to or better than peat.

Natural grass areas in high-traffic and stress locations are being converted into artificial grass by inconsistent moisture conditions in root-zone and poor grass conditions. As an alternative solution to this method, natural grass was planted instead in a washed sand without organic matter and with a constantly moving water table and no overhead irrigation. Water consumption and surface quality after heavy machinery exposure was measured. A significantly increase in the potential for traffic and play was observed, along with water savings of up to 85% compared with normal overhead irrigation amounts for similar surfaces (golf course tees).

The agronomic benefits of endophytic Epichloë fungi for the performance of ryegrass (Lolium spp.) and fescue (Festuca spp.) species were first reported in the 1980s. Various Epichloë endophyte species and strains have been shown to produce a series of different alkaloids with considerable impact on insect pests and grazing animals, some effects on nematodes and diseases, and improvements in plant stress tolerance. However, the impact of these alkaloids on plant performance and turf resilience varies across environments, and often relates to specific insect pressures and stressful summer conditions. Over 40 insect pests and diseases have been documented as responding to endophyte infection.

As many Epichloë fungi are seed transmitted, endophyte transmission to the seed is controlled by the levels found in the parent plants and how well the endophyte is maintained during seed production. Endophyte viability in seed lots can drop during storage and transport, especially when stored under high temperatures and humidity. Endophyte growth into seed during seed production can be influenced by the weather, use of fungicides and growth regulators, and the timing of combining after swathing. In the United States, the endophyte infection levels in breeders’ seed of the cultivars used in the National Turfgrass Evaluation Program trials have been reported but currently, no standards exist for labeling cultivars delivered with high endophyte levels. Without suitable protocols and standards, challenges exist in delivering high endophyte infection levels to tall fescue (Festuca arundinacea Schreb.), ryegrass, and fine fescues.