International Turfgrass Society Research Journal最新文献

A total of 277 zoysiagrass growing naturally in the local regions was collected per region, and a morphological classification was conducted through statistical analysis using morphological modification. For a diversified analysis through morphological characteristics, the main trait related to morphological characteristics was analyzed, and as a result of analyzing the classificational relationships of zoysiagrass, zoysiagrass that were collected according to leaf width, stolon internode thickness, number of stolon internode, number of seed per spikelet, seed length, and seed length/seed width ratio were classified into four groups. The major morphological traits observed in each individual group were compared to the morphological characteristics of native zoysiagrasses described in the reference, and three of the groups were assumed to be Zoysia japonica (group A), Zoysia sinica (group B), and Zoysia matrella (group D). One of the groups was assumed to be a hybrid and/or mutant with intermediate characteristics.

Demethylation inhibitor (DMI) fungicides are commonly used to suppress dollar spot and other major turfgrass diseases. Repeated applications of these fungicides, however, have been reported to result in turfgrass injury when applied during high temperatures. Field studies were conducted on both annual bluegrass and creeping bentgrass fairways at the Joseph Valentine Turfgrass Research Centre located in University Park, PA. Applications were made every 14 days at the high label rates and in two application volumes (409 and 818 L ha⁻¹). The objectives of this study were to (1) evaluate variation in turfgrass injury among nine commercially available DMIs when applied to annual bluegrass and creeping bentgrass fairways and (2) elucidate the influence of application volumes on turfgrass injury. Triticonazole was found to cause significant injury to annual bluegrass, but no injury was observed on creeping bentgrass. Mefentrifluconazole had the lowest injury compared to all other treatments on both grass species. Propiconazole caused darkening and thickening of foliage on both annual bluegrass and creeping bentgrass while triadimefon caused injury on creeping bentgrass but not on annual bluegrass. Application volume influenced injury only on a few select dates. Generally, injury to both turfgrass species started to decline after the third application and completely waned approximately 2 weeks after the final application.

As summer droughts become more common and water resources more precious, some golf courses in Scandinavia are turning to lower quality irrigation water to irrigate their courses. We visited seven golf courses on the Baltic coast of Sweden using lower quality irrigation water to interview superintendents and to take soil and water samples for salinity analysis. Four of the seven golf courses experience salinity stress regularly, primarily in a 6–8 week period in July and August. Soil and water samples taken at the seven golf courses in October 2024 generally did not exceed salinity thresholds for cool-season turfgrasses, but retesting of water and soil will be conducted again in 2025 with at least one of the sampling events conducted during the summer period in which salinity stress symptoms usually occur.

Unraveling the role of environmental drivers and native microbial communities in sandy soils of golf course putting greens is imperative for more sustainable turf management practices. In this project, the soil rhizosphere microbial community of the Golf de Pals (Girona, Spain) putting greens is assessed in a chronosequence of 14- and 56-year-old greens. Note that 16S rRNA and ITS2 (where 16S rRNA is 16S ribosomal RNA and ITS is internal transcribed spacer) paired-end amplicon sequencing (16S-metabarcoding) was used to determine both the soil bacterial and fungal community, respectively, in a 2-year-long trial to determine microbial taxon richness, community composition, and abundances of taxa involved in N and C cycling and other plant growth-promoting rhizobacterium traits. The analysis of beta diversity showed a significant effect by the age and location. Main phyla were Proteobacteria, Actinobacteria, Chloroflexi, Acidobacteria, Planctomycetota, and Desulfobacterota, with significant differences depending on the location of the putting green. Mantel test revealed that the environmental parameters with higher and significant contribution to soil microbial diversity were solar radiation—photosynthetic photon flux density and physicochemical parameters such as, in order of importance, soil moisture and temperature, electric conductivity, organic matter, organic carbon, N_Kjeldahl, NO₃⁻, P_Olsen, P_Total, and sulfates. Main phyla significantly influenced by soil parameters were Crenarcheota, Acidobacteria, Desulfobacterota, Chloroflexi, Actinobacteria, Firmicutes, and Gemmatimonodata, whereas FAPROTAX (Functional Annotation of Prokaryotic Taxa) assessment revealed that the main potential metabolic pathways associated with the most predominant microbial community were nitrite respiration, nitrous oxide denitrification, nitrite denitrification, denitrification, and dark sulfide oxidation and methanogenesis.

The effect of winter soil heating to improve turf quality under shade stress was evaluated on a golf course putting green located in a mountainous area of Japan. The research was done at the putting greens in Maple Point Golf Club (Yamanashi, Japan) with creeping bentgrass (Agrostis stolonifera L.) and sandy soil. Heating treatments were conducted from early December to late February of the following year on greens that were not exposed to direct sunlight for 45 days in winter using buried electric heating wires. Surveys were conducted on a heated green in the shade, a green in the shade without heating, and a green with good sun exposure without heating. Soil temperature, light condition, root mass, drone normalized difference vegetation index, and leaf fructan content were measured. Results showed that root growth was maintained, and turfgrass quality was improved by heating in the shaded putting green.

The primary benefits of turfgrass sod include rapid greenery and soil coverage, but its production causes concerns about soil losses at production sites. Soil adheres to the grass root system during harvesting and is removed from the sod farm, which in the long run might lead to soil degradation on the sod farm. In this study, we investigated sod thickness and the removal of organic and mineral matter when harvesting 24 fields representing 12 Norwegian sod farms in 2022 and 2023. On each field, 10 sod strips were randomly chosen, and five sod plugs were collected from each strip. Sod thickness was measured using a sliding gauge. Sod mineral matter (SMM: soil and thatch mineral matter) and sod organic matter (SOM: soil and thatch organic matter) contents were quantified by loss on ignition at 550°C. Management and field properties were also documented. Results showed an average amount of mineral matter in the sod strips of 36 Mg ha⁻¹ for all fields but with significant variation among fields (p < 0.001). The average SOM content was 10 Mg ha⁻¹. Mean sod thickness was 15.4 mm and had a strong correlation with SOM (r = 0.8) but only a moderate correlation with SMM (r = 0.6). Soil water content and surface hardness at harvest affected sod thickness and SMM only slightly. Sod harvesters with twin heads harvested significantly thicker sod strips and removed more mineral matter than harvesters with single cutting heads. Soil texture did not have a significant impact on sod thickness or mineral matter removal.

Thirty-seven turfgrass samples expressing dollar spot symptoms were collected in summer 2020 on golf courses in Sweden, Denmark, United Kingdom, Germany, Portugal, and Spain. The fungi were isolated at Norwegian Institute of Bioeconomy Research (NIBIO) Turfgrass Laboratory (Norway) and sent for molecular identification using sequencing of regions of ITS (internal transcribed regions of the ribosomal DNA) and calmodulin. Clarireedia homoeocarpa was identified in four turfgrass samples and Clarireedia jacksonii was identified in 11 turfgrass samples. From seven turfgrass samples, the isolated fungi were not Clarireedia spp., but Waitea circinata, Fusarium culmorum, and Fusarium oxysporum. This suggests dollar spot is not always accurately identified from foliar symptoms in the field.

Golf courses are increasingly reliant on suboptimal water sources, particularly in arid regions, many of which exhibit elevated levels of dissolved bicarbonate (HCO₃⁻). The assessment of bicarbonate levels in irrigation water, in conjunction with the examination of other ions, are believed to be primary contributors to soil physical issues, including diminished infiltration rates and restricted plant rooting. Bicarbonate and, to a lesser extent, carbonate (CO₃²⁻) are commonly present in high-pH water. While their concentrations in irrigation water are variable, the primary concern lies in the imbalance of these ions with Na, Ca, and Mg. Such imbalances can lead to the precipitation of relatively insoluble Ca and Mg carbonates. The removal of soluble Ca and Mg through precipitation leaves Na in solution, promoting sodic conditions that deteriorate soil structure and potentially clog soil pores. While high levels of bicarbonate and sodium in irrigation water suggest that acidification is required, the question arises as to whether irrigation water acidification is necessary when ratios of Ca/Mg and HCO₃/CO₃ are high but levels of sodium are low. The study was conducted at New Mexico State University and involved four irrigation water treatments, including N-pHuric acid and WaterSOLV™ Curative, which are intended to decrease HCO₃/CO₃ in irrigation water. After 2 years, Kentucky bluegrass irrigated with N-pHuric acid-amended water exhibited greater soil hydraulic conductivity compared to other treatments. During the first year, Kentucky bluegrass irrigated with N-pHuric acid demonstrated the greatest visual quality and the greatest Dark Green Color Index; however, these results were not apparent in the second year.

We report on a continuous 5-year study of the total bacterial number in the root zone of a sandy soil putting greens on golf courses in Japan using the SOFIX (Soil Fertility Index) analysis technology. SOFIX is a new soil analysis technology where the number of soil bacteria can be evaluated. The study revealed a trend of seasonal changes in the total bacterial number during the turf growth season. The study also revealed a relationship between turfgrass growth, putting green management methods, and soil analysis values including physical, chemical, and biological properties. These results indicated that the SOFIX analysis technology can track changing soil bacterial number, and it can be used as a guideline for stable maintenance of a sandy soil putting green on a golf course.