Turfgrass Cover Research Articles

Late-spring Turfgrass Establishment without Herbicides

Spring establishment of turfgrass that is managed without herbicides is subject to weed competition, resulting in reduced turfgrass cover. The objective of this experiment was to find an acceptable method for spring turfgrass establishment without the use of pesticides. Thirty-six treatments consisting of three soil amendments combined with three turfgrass species or mixes, and four topdressings or fertilizers in a randomized complete block design were tested. Nutrient-deficient fill soil, fill soil blended with topsoil, and fill soil blended with leaf compost were used as growing media. ‘Firenza’ tall fescue (Schedonorus arundinaceus), an 80/20 mix of ‘Nu Destiny’ kentucky bluegrass (Poa pratensis) and ‘Nexus XD’ perennial ryegrass (Lolium perenne), respectively, and ‘Firefly’ hard fescue (Festuca trachyphylla) were grown with topdressings consisting of biosolids, ash-amended biosolids, 16N–12.2P–3.3K starter fertilizer, and an unfertilized control. The treatments were mowed at 3 inches about once per week. Irrigation was supplied by an overhead sprinkler system (1 inch/week). During the 2010 field study, treatments of tall fescue established in a leaf compost–amended root zone were significantly denser and had a greater percentage of cover (P ≤ 0.05) compared with all other treatments. In 2011, treatments of tall fescue established in fill soil– and leaf compost–amended soils were significantly denser and had a greater percentage of cover (P ≤ 0.05) compared with all other treatments. Kentucky bluegrass/perennial ryegrass and hard fescue treatments had significantly lower (P ≤ 0.05) levels of establishment compared with tall fescue. Topdressing treatments resulted in no significant difference (P ≤ 0.05) in turfgrass establishment.

Comparing methods to quantify cover in turfgrass research

AbstractTurfgrass cover can be assessed qualitatively using visual ratings, but quantitative turfgrass cover measurements are desired for producing unbiased data. Digital image analysis and point intercept are two quantitative percent cover data collection methods used in turfgrass research. A potential weakness of digital image analysis is the difficulty in evaluating color variation. Considering this, a series of controlled environment and field experiments were conducted to evaluate the accuracy of the point intercept method compared to using a digital grid, digital image analysis, and visual ratings when utilized in turfgrass research. To explore this topic, four experiments were conducted in Corvallis, OR, and one in New Brunswick, NJ. Results from research conducted in Corvallis, OR, determined that the closest point intercept spacing (2.5 cm) resulted in a percent cover that was not statistically different from the known cover and the lowest variance, but the greatest amount of time required to collect the data. Digital image analysis was the most consistent method for measuring percent cover when a known percent cover was being quantified. The estimate of the percent dollar spot cover was reduced by a single pigment application regardless of the data collection method. In the absence of pigment applications, the point intercept frame, digital image analysis, and visual ratings were well‐correlated methods used to assess dollar spot cover. Digital image analysis was not correlated with the other data collection methods when used to evaluate percent anthracnose cover. The research conducted in New Brunswick, NJ, determined that the point intercept method and digital image analysis are well‐correlated methods for quantifying turfgrass establishment from seed.

Contemporary Challenges and Opportunities for Improved Lawn Weed Management: Insights from U.S. Lawn Care Operators

Lawns provide valuable ecological, economic and social services. Both the quantity and quality of the turfgrass affect the level of the services delivered. Unwanted weed infestations can degrade lawn quality and decrease the value of these services for lawn users and others. For example, Brosnan et al. reported that athletic fields with weed cover not only decreased aesthetic quality but also resulted in increased surface hardness and a concomitant increase in potential athlete injuries and soil erosion. Contemporary research pertaining to pest influences on lawn quality and management responses is sparse. We hope to begin filling that gap with findings from a recent study of U.S. lawn care operators about the challenges and opportunities omanaging Poa annua, an emergent threat to sustainable lawn management (USDA-NIFA Specialty Crops Research Initiative (SCRI) Grants Program (award #: 2018-51181-28436). Estimates for residential- and commercial-lawn cover in the United States (U.S.) range from 58,000 km2 to 120,000 km2 with total turfgrass cover (inclusive of golf courses, parks, schools, roadsides) estimated at 163,800 km2. The Federal Highway Administration (FHWA) estimated that there are 20,436 km2 of grassed rights of way (roadsides) in the U.S. The total U.S. urban area in 2010 was estimated at 802,053 km2. Together, we can estimate turf cover between 7 and 18% of U.S urban areas, including lawns as the primary turf surface along with parks, athletic fields, golf courses, and roadsides. The professional lawn care industry employed 295,000 workers and represented an $18.5 billion market value in 2002. Despite its size, the U.S. lawn care industry defies simple characterization in part due to its heterogeneity. Lawns may provide valuable ecosystem services, including wildlife habitat, water infiltration, and moderation of the urban heat-island effect as well as aesthetics and open space for recreation. Apart from offering economic and ecological services, lawns and their management can be an important component of community social character and culture. Effective weed management in lawns assures sustainable delivery of all of these services, such that lawns are uniform and free from potentially troublesome weed species, such as Poa annua which ranks as the #1 most troublesome weed in turfgrass systems.

Vegetation cover change during a multi-year drought in Los Angeles

Vegetation in urban areas can provide many ecosystem services, such as cooler temperatures. In water-limited climates, maintaining benefits from vegetation during droughts requires significant water inputs and can be challenging due to the uneven effects of drought on vegetation. Here, we tracked changes in vegetation cover in Los Angeles, California using airborne hyperspectral imagery acquired annually from 2013 to 2018 and coinciding with the exceptional 2012–2016 California drought. Subpixel fractions for trees, turfgrass, non-photosynthetic vegetation (NPV; e.g., senesced plant material), and non-vegetated urban surfaces were mapped at 18 m spatial resolution using Multiple Endmember Spectral Mixture Analysis. We quantified cover changes through time, comparing how different physiographic regions of the city experienced vegetation change and assessing changes based on income and outdoor water use. From 2013 to 2018, overall turfgrass cover decreased (−17%) and NPV cover increased (+22%). Tree cover was more stable but decreased in 2018 (−6%). The inland valleys consistently lost more turfgrass than coastal areas. Higher income and water use areas had larger absolute changes in vegetation cover, likely due to their higher baseline of vegetation cover.

Establishing seeded tall fescue with covers and drip irrigation methods

AbstractThe 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.

Responses to elevated carbon dioxide for postdrought recovery of turfgrass species differing in growth characteristics

AbstractElevated CO2 concentration affects plant responses to drought, but its effects on poststress recovery for perennial grass species with different growth habits are unclear. The objective was to determine how stoloniferous and bunch‐type grass species may exhibit differential responses to elevated CO2 concentration during drought stress and postdrought recovery upon rewatering due to different growth characteristics. Stoloniferous creeping bentgrass (Agrostis stolonifera L.) ‘Penncross’ and bunch‐type tall fescue [Schedonorus arundinaceus (Schreb.) Dumort] ‘Sitka’ were grown at ambient CO2 (400 μl L−1) or elevated CO2 concentration (800 μl L−1) repeated in four growth chambers for 28 d, subsequently subjected to either irrigation (control) or drought stress (irrigation completely withheld) for 28 d, and then rewatered for 18 d. During drought stress, both species exposed to elevated CO2 maintained higher turf quality, leaf water content, and membrane stability than plants at ambient CO2. Elevated CO2 caused significant increases in the viability of stolon–node meristematic tissues in creeping bentgrass under drought stress and rapid regeneration of daughter plants during rewatering, as shown by increased shoot biomass and percent turfgrass cover. Elevated CO2 had no significant effects on the viability of crowns with meristematic tissues in tall fescue during drought nor shoot biomass or percent turfgrass cover during rewatering. The stoloniferous grass species was more responsive to elevated CO2 compared to bunch‐type species for poststress recovery, as creeping bentgrass rapidly regrew and recovered from drought damages. Such information is of great importance for making appropriate turfgrass selections and breeding improvements in growth habits in areas with prolonged drought and the anticipated rising CO2 levels.

Spatial contagion structures urban vegetation from parcel to landscape

Abstract Residential yards are a significant component of urban socio‐ecological systems; residential land covers 11% of the United States and is often the dominant land use within urban areas. Residential yards also play an important role in the sustainability of urban socio‐ecological systems, affecting biogeochemical cycles, water and the climate via individual‐ and household‐level behaviours. Spatial contagion has been observed in yard vegetation in several cities, potentially due to social norms that compel neighbours to emulate or conform to specific aesthetic qualities or management regimes. Residents may feel obliged to mow their front yards or prune their trees, creating patterns of spatial autocorrelation in residential neighbourhoods. In this study, we examined the spatial autocorrelation of several yard vegetation characteristics in both front and backyards in Boston, MA, USA. Our study area included 1,027 Census block groups (sub‐neighbourhood areas) and 175,576 parcels with matched front‐backyard pairings (n = 351,152 yards in total) across Boston's metropolitan area. We spatially defined ‘neighbours’ in five ways to better account for the potentially variable nature of how conformity or contagion manifests in empirical terms. We anticipated front yards to have stronger spatial autocorrelation due to the more publicly visible nature of these green spaces. We found positive and significant spatial autocorrelation in all measured vegetation variables, in both front and backyards. Unexpectedly, spatial autocorrelation tended to be higher in backyards for tree canopy variables but higher in front yards for turf grass cover. Among block groups, different socio‐economic variables, such as median household income, predicted spatial autocorrelation of vegetation characteristics. Our results were sensitive to how neighbours were spatially defined. Our results further underscore the importance of backyards as critical areas for sustaining an urban tree canopy, and show that spatial patterns vary across different social groups. The importance of ‘neighbour’ definition indicates opportunities to think carefully about the mechanisms driving spatial autocorrelation and the scales at which patterns develop. The identification of these mechanisms will have important implications for scales of policy and implementation for urban and suburban greening. A free Plain Language Summary can be found within the Supporting Information of this article.

Response of Retail Lawn Seed Products during Acute Drought and Recovery

Consumers often have multiple choices when purchasing retail lawn products in stores. In this study, we evaluated the acute drought performance of locally available retail lawn seed products (mixtures or blends) at two mowing heights of 2.5 and 3 inches. We hypothesized that the species present in the products and the height-of-cut differentially influence the drought resistance and recovery of the mixtures and blends. In Fall 2016 and 2017, 28 different products consisting of 25 mixtures and 3 blends of turfgrass seeds were established under a fully automated rainout shelter at the St. Paul campus of the University of Minnesota. The drought treatments lasted for 67 days in 2017, and 52 days in 2018; both the 2017 and 2018 treatments were followed by a recovery period. Data were obtained during acute drought treatments and recovery periods for visual turfgrass quality and green turfgrass cover using digital images of the plots. During the first year, several products displayed higher green stability (or the ability to remain green) at the 3-inch height-of-cut compared with the 2.5-inch height-of-cut. Products with tall fescue (Schedonorus arundinaceus) and fine fescue (Festuca sp.) as dominant species generally performed better during the drought treatments, whereas an increasing presence of perennial ryegrass (Lolium perenne) and kentucky bluegrass (Poa pratensis) decreased the visual drought performance of the products. During the recovery period, an effect of the interaction between mowing height and the date of data collection on the percentage of green cover was observed: the lower mowing height improved the early recovery of green cover after acute drought. These findings suggest that consumers in the upper midwestern United States and areas with a climate similar climate to that of St. Paul, MN, who are challenged with multiple choices of lawn seed products should choose products containing a higher tall fescue content and adjust their mowing heights to optimize recovery.

An evaluation of mat hybrid turfgrass systems under simulated traffic

AbstractThe addition of synthetic fibers to natural grass athletic fields forms a hybrid turf system, and this system claims to increase traffic tolerance and playability. The objectives of this research were to evaluate the physical effects of simulated traffic on two hybrid, carpet‐based mat systems (Eclipse and Hero) with Kentucky bluegrass (Poa pratensis L.), compared to a non‐hybrid control (100% Kentucky bluegrass). Field research was conducted in 2018 at Michigan State University (MSU), Iowa State University (ISU) and the University of Tennessee (UT) to evaluate the percent green cover, surface hardness, and shear resistance under 25 simulated traffic events (STE). Percent green cover across all treatments was reduced after 25 STE. After 25 STE the hybrid systems had greater percent green cover (Eclipse 49% and Hero 48%) than the non‐hybrid control (33%) at the ISU location. Surface hardness values differed between treatments on many rating dates. The hybrid systems reported higher surface hardness values, but these values were never above 100 Gmax. These results indicate that the Eclipse and Hero systems can offer a safe and stable surface even if turfgrass cover is reduced.

Water use and drainage of subtropical, mixed landscapes varies with turf coverage and season

We conducted a three-year drainage lysimeter study of mixed (woody plant-turf) landscape water demand relative to reference evapotranspiration, drainage, and plant growth in humid, subtropical central Florida. The aim was to develop information to guide more efficient water planning, landscape design, and irrigation management in a seasonally dry monsoon climate using three representative landscape species – southern magnolia (Magnolia virginiana), sweet viburnum (Viburnum odoratissimum), and St. Augustinegrass (Stenotaphrum secundatum) – at turf coverage of 90, 75, and 60% of the total landscape area. Water inputs (daily rainfall, irrigation) and drainage were recorded with a datalogger to calculate monthly actual evapotranspiration (ETA) for each lysimeter using a water balance approach. Growth was measured non-destructively (magnolia height, canopy and trunk diameter, viburnum dry mater, canopy cross section, and volume) every three weeks, while turf clippings were collected during the spring to late fall growing season. Woody plants imbedded in turf with ostensibly deeper root systems underlying turfgrass roots were more efficient at scavenging water, minimizing drainage, and leaching risk. Reducing turfgrass coverage to 60% diminished drainage by 70 cm in the wet season and 50 cm in the dry season compared to 90% turfgrass cover, and increased rainfall utilization rate to 0.81 compared to 0.40 for 90% turf across both seasons. Mixed turf-woody plant landscape ETA differed minimally across turf coverage treatments during the dry season, with approximately 70% of reference ETA versus 90% during the wet season, likely due to less surface evaporation. To conserve water and reduce drainage during the monsoonal dry season, mixed turf-woody plant landscape irrigation can be scheduled based on water demand at 70% of local evapotranspiration (0.7 Plant Factor). These results give water suppliers and landscape architects tools to design urban landscapes and develop regulations to efficiently promote and track mixed landscape irrigation water consumption in a monsoonal climate with a pronounced dry season. Further, water managers can reduce drainage and risk of groundwater pollution by encouraging design of landscapes with woody plants imbedded in turfgrass to scavenge water moving below the turfgrass root zone.

Species, cultivar and seeding rate effects on non‐irrigated, pesticide‐free athletic fields playing surface quality

AbstractMaintaining high‐quality athletic field playing surfaces without the use of synthetic pesticides is challenging. Little research is available regarding the best overseeding strategies for non‐irrigated, pesticide‐free, cool‐season athletic fields. The objectives of this study were to determine the effects of turfgrass species, cultivar, seeding rate, and seasons on turfgrass color, dark green color index (DGCI), cover, weeds, overall quality, surface hardness and volumetric water content when overseeded under trafficked conditions. Experiments were set out as randomized complete block designs arranged in a 3 × 2 × 2 factorial with three replications. Treatments consisted of three turfgrass species, perennial ryegrass (Lolium perenne L.) (PRG), tall fescue [Schedonorus arundinaceus (Schreb.) Dumont] (TF), and Kentucky bluegrass (Poa pratensis L.) (KBG), two overseeding rates, low and high, and two cultivar types, inclusion or exclusion of cultivars on the Turfgrass Water Conservation Alliance (TWCA) list. Mean responses across three locations and three years indicated that species selection has the most influence on successful overseeding with little differences detected between rate of overseeding or cultivar selection. Perennial ryegrass, regardless of seeding rate, had significantly higher color, quality, percent turfgrass cover, desirable species index, and least percent weed cover compared with TF or KBG. Based on the results of this study, the most effective overseeding strategy for improving playing surface conditions on heavily trafficked, non‐irrigated, pesticide‐free, cool‐season athletic fields is overseeding with PRG.

Comparison of mechanical removal of perennial ryegrass overseeding out of bermudagrass to chemical transitions

AbstractIn the fall, bermudagrass athletic fields are overseeded with perennial ryegrass [Lolium perenne L.] to provide a uniform playing surface to slowed or dormant bermudagrass. Chemical techniques have been utilized for quick and efficient spring transition of perennial ryegrass. Fraise mowing has been identified as a tool that can aid in ryegrass transition in the spring. These studies were to determine the effectiveness of spring transition comparing mechanical removal of perennial ryegrass overseeding to traditional techniques on ‘Riviera’ bermudagrass [Cynodon dactylon (L.) Pers.]. In 2017, field studies were conducted at the University of Tennessee Center for Athletic Field Safety (Knoxville, TN) and the Oklahoma State University Turfgrass Research Center (Stillwater, OK). The seven treatments for the study were: fraise mow at 6.4 mm from the grass surface, fraise mow at 12.7 mm from the grass surface, fraise mow at 19.1 mm from the grass surface, spray application of trifloxysulfuron at the 27.8 g ha−1 with non‐ionic surfactant at 0.25% v/v, spray application of foramsulfuron at the 28.9 g ha−1, scalping (19.1 mm) with a rotatory mower, and an untreated control. Treatments were initiated on 11 May 2017 in Stillwater, OK USA and 17 May 2017 in Knoxville, TN USA. Plots were monitored for six weeks following treatment application. Fraise mowing at 12.7 mm was identified as the optimum depth for perennial ryegrass transitioning in this study compared to chemical transitions. This study found that the fraise mowing at 12.7 mm removed more perennial ryegrass and maintained percent green turfgrass cover throughout the study. However, if time of use for the turfgrass area is not a primary concern then depths greater than 12.7 mm are effective at perennial ryegrass removal but delay spring green‐up.

Influence of cultivation method, seeding rate, and fertilizer rate on the establishment of creeping bentgrass for putting green renovation

AbstractDuring putting green renovation in northern regions of the United States, golf course superintendents must select a method to quickly establish creeping bentgrass (Agrostis stolonifera L.)(CBG). This study aimed to assess the impact of cultivation method, seeding rate, and cumulative starter fertilizer rate on CBG establishment during putting green renovation. A field study on putting greens at the Joseph Valentine Turfgrass Research Center (University Park, PA) was initiated in late summer–autumn of 2017 and 2018. Cultivation treatments included slicing + 0.5‐inch hollow tines, slicing + 0.25‐inch hollow tines, slicing only, surface dimpling with the Jobsaver attachment, and no cultivation. Seeding rates included 0.75 and 1.5 lb seed 1,000 ft−2 with a 50–50 blend of ‘Penn A‐1’ and ‘Penn A‐4’ CBG. Cumulative starter fertilizer treatments were 0.5–0.4–0.3, 1.0–0.9–0.6, or 1.5–1.3–0.8 lb N–P–K 1,000 ft−2. Seedling vigor and turfgrass cover were visually assessed at 1 wk and 6, 10, and 36 wk after seeding, respectively. Slicing alone produced turfgrass cover equal to or greater than slicing + hollow‐tine cultivation. At the high seeding rate, surface dimpling produced similar turfgrass cover to treatments involving slicing. The 1.5 lb 1,000 ft−2 seeding rate increased the turfgrass cover of CBG compared with 0.75 lb 1,000 ft−2. Establishment rate improved as cumulative fertilizer rates increased. The results indicate that slicing alone is effective for establishing CBG during late summer and autumn in sand rootzone putting green renovation programs and may be more cost‐effective than core cultivation.

Effects of vegetation on the spatial and temporal variation of microclimate in the urbanized Salt Lake Valley

Land cover characteristics can produce changes in spatial and temporal variability in potential temperature (θ) at scales that are relevant to city inhabitants. Using data from 60 sensors positioned in five urban parks and surrounding residential neighborhoods in the semi-arid Salt Lake Valley, we evaluated the effect of turfgrass cover versus tree shading on spatial and temporal variation in microclimate in a semi-arid urban area. Our results indicated that the replacement of vegetation by impervious surfaces plays a role in microclimatic homogenization. Tree shading was associated with higher spatial variability of θ during the day, while turfgrass cover was associated with higher spatial variability of θ at night. Contrary to our expectation of tree shading governing daytime θ, we also found turfgrass cover to have an efficient cooling effect. This suggests a prominent role of turfgrass evapotranspiration enhanced by high atmospheric evaporative demand, high soil moisture availability, and increased radiation loads that are characteristic of semi-arid urban landscapes. Given that turfgrass cover was also associated with reduced θ at night, mixed tree and grass landscapes may be effective in alleviating the urban heat island effect in semi-arid urban settings.

Drought response of urban trees and turfgrass using airborne imaging spectroscopy

Vegetation growth and physiological functioning, including carbon uptake and transpiration, can be strongly affected by drought. During water-limited conditions, urban vegetation may be limited in its ability to provide ecosystem services, such as shading and evaporative cooling. While there has been extensive research on drought response in natural vegetation and agricultural systems using remote sensing, drought impacts on urban vegetation have remained understudied. With >50% of people worldwide living in cities and the increased potential for future droughts, it is important to understand how urban vegetation will respond and to evaluate potential impacts. Here, we used repeat flights of NASA airborne imaging spectroscopy (AVIRIS and AVIRIS-NG) to quantify the responses of common urban tree species and turfgrass in downtown Santa Barbara, California, USA to the 2012–2016 California drought. The effects of the drought on vegetation were quantified using several spectral indicators: fractional cover from multiple endmember spectral mixture analysis (MESMA), vegetation indices, and continuum removed absorption features. We used existing tree crown object polygons that were classified to species and had associated estimates of pre-drought leaf area index and biomass. We also included polygons of turfgrass parks and recreational fields. All tree species and turfgrass had four or more spectral indicators with significantly lower mean values (p < 0.05) during the drought in 2014, and evidence of recovery was observed for some species in 2017, which was after the drought had ended. In general, needleleaf and native trees were more affected than broadleaf and non-native trees, respectively, but with considerable interspecific variability. Based on the spectral indicators, turfgrass cover senesced in the middle of the drought but recovered soon after the drought ended, whereas the majority of tree species had not fully recovered. Mean green vegetation cover declined in most tree canopies during the drought, primarily exposing paved surfaces and/or non-photosynthetic vegetation, depending on the site type and tree patch size. Drought impacts as expressed in spectral indicators were generally more severe in tree patches with high pre-drought leaf area index, suggesting that denser, leafier canopies were more difficult for trees to maintain during the drought. Most spectral indicators were correlated with one another (R > 0.4), suggesting co-occuring adjustments of greenness, water content, and plant pigments.

Optimizing Pre-germination Techniques for Kentucky Bluegrass and Perennial Ryegrass1

Abstract Many intensively trafficked areas such as athletic fields and golf courses require constant overseeding to maintain suitable turfgrass cover. Rapid seed germination and development are critical to managing these high wear areas. The objectives of this research were to determine the effect of water aeration, seed soaking duration, and water temperature on mean germination time (MGT) and final germination percentage (FGP) of Kentucky bluegrass (Poa pratensis L., KBG) and perennial ryegrass (Lolium perenne L., PRG). Two separate controlled environment studies were conducted. PRG soaked in aerated water from 8 to 48 h had a 20% decrease in MGT compared to an untreated control, while treated KBG decreased MGT by only 10% compared to an untreated control. Soaking duration and water temperature had significant effects on KBG. KBG MGT was optimized at 20 C (68 F) water temperature with a soaking duration of 24 h. MGT of PRG was optimized when soaked for 8 h while water was aerated. There was no significant difference in FGP for any of the treatments tested. Index words: turfgrass, aeration, seed soaking. Species used in this study: Kentucky bluegrass (Poa pratensis L.); perennial ryegrass (Lolium perenne L.).

Registration of ‘MSA 2‐3‐98’ St. Augustinegrass

‘MSA 2‐3‐98’ (Reg. No. CV‐284, PI 689102) is a cold‐tolerant, high‐quality St. Augustinegrass [Stenotaphrum secundatum (Walt.) Kuntze] developed at Mississippi State University. MSA 2‐3‐98 was released on 19 Apr. 2006 from Mississippi Agricultural and Forestry Experiment Station. MSA 2‐3‐98 offers many advantages compared with other St. Augustinegrass cultivars. Leaf length, leaf width, internode length, and internode diameter of MSA 2‐3‐98 were significantly smaller than ‘Floratam’ and ‘Raleigh’. The more diminutive morphology of MSA 2‐3‐98 allows it to establish a denser turfgrass canopy with finer leaf texture. Cold tolerance of MSA 2‐3‐98 was evaluated from spring assessments of percentage green turfgrass cover and overall plot green‐up. The cold tolerance of MSA 2‐3‐98 was similar to Raleigh but outperformed Floratam. MSA 2‐3‐98 turfgrass quality tended to be greater than ‘Delmar’, Floratam, and Raleigh. Gray leaf spot severity on MSA 2‐3‐98 was variable among locations where the disease was evaluated. MSA 2‐3‐98 has greater turfgrass quality than Raleigh, with similar cold tolerance.

Impact of Mowing Height and Nitrogen Fertility on Crabgrass Cover in ‘RTF' Tall Fescue1

AbstractTall fescue (Festuca arundinacea Shreb.) has exceptional utility as a low maintenance lawn in the transition zone. However, during the summer smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.] infestations can reduce the aesthetic value and function of the turf and lead to a thinning of the tall fescue stand, noticeable after the crabgrass plants have senesced. Research was conducted to evaluate the impact of mowing height and nitrogen fertility on smooth crabgrass plant counts and tall fescue cover in Virginia Beach, VA. Plots were mowed at either 6 cm (2.5 in) or 10 cm (4 in) and received 49, 171, or 220 kg of nitrogen annually per hectare (44, 152, and 196 lb.A−1). Mowing at 10 cm with the highest level of fertility resulted in the most turfgrass cover among all the treatment combinations. Mowing at 10 cm as opposed to 6 cm resulted in less smooth crabgrass plants, regardless of nitrogen fertilization rate.Index words: fertilization, turfgrass, weed control.Species used in this study: Smooth crabgrass [Digitaria ischaemum (Schreb.) Schreb. ex Muhl.]; tall fescue [Festuca arundinacea Shreb. synonym Schedonorus phoenix (Scop.) Holub].

Impact of Soil Water Content on Hybrid Bermudagrass Athletic Fields

Soil water content (SWC) influences the consistency and performance of athletic field surfaces. Two studies were conducted at the University of Tennessee Center for Athletic Field Safety, Knoxville, TN, to determine how SWC affects wear tolerance of hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy, ‘Tifway’] on root zones composed of either silt loam (cohesive) or sand meeting US Golf Association specifications (noncohesive). Soil water content treatments for cohesive root zones averaged low (0.06–0.13 m3 m−3), medium (0.14–0.21 m3 m−3), medium‐high (0.22–0.29 m3 m−3), and high (0.30–0.37 m3 m−3); comparatively, SWC on noncohesive averaged low (0.05–0.11 m3 m−3), medium (0.12–0.19 m3 m−3), and high (0.20–0.27 m3 m−3). Differences in the amount of ranges between root zones were due to plant available water of the soil texture. Plots were subjected to 50 traffic events for 5 wk each fall over a 2‐yr period. Green turfgrass cover was reduced four times faster at high SWC than the low and medium SWC treatments on cohesive soil. All SWC treatments on noncohesive soil lost green turfgrass cover at a predictable rate. Surface hardness increased as SWC decreased for both root zones. Turfgrass shear strength decreased with traffic for all treatments on cohesive soils. Soil water content of noncohesive soils did not compound the effect of traffic on turfgrass shear strength. The optimal mean SWC ranges to maximize hybrid bermudagrass wear tolerance on cohesive soils were low to medium, and low to medium on noncohesive soils.

Evaluation of bermuda and paspalum grass types for urban landscapes under saline water irrigation

ABSTRACTIn the arid regions, turfgrass cover is an integral part of landscape to protect the soil from erosion, enhance the aesthetic value, and improve the microclimate. The salinity and the scarcity of fresh water of the arid region are the major challenging factors in turfgrass production. Therefore, the need for salt tolerant turfgrass with functional quality is necessary to improve the turf performance. The detrimental effects of salinity include growth suppression, and lowered osmotic potential ultimately leading to firing of the leaf blades. In this context, the study was undertaken to determine the relative salt tolerance and growth response of turfgrass genotypes in order to recommend turfgrass cultivars that can tolerate high salinity irrigation and maintain excellent visual and functional qualities under United Arab Emirates (UAE) condition. The paspalum cultivars maintained the highest succulence percentage compared to the bermudagrass cultivars under enhanced salinity levels. The shoots count, fresh weight (FW), and dry weight (DW) were found highest in paspalum types. The chlorophyll a, chlorophyll b and the total chlorophyll content was found higher in bermuda grass types under high salinity levels. The bermudagrass cultivars showed significantly higher carotenoids, anthocyanins and proline compared to the paspalum types under salt stress condition. In the case of princess 77 and Yukon, an inherently high amount of proline was recorded which confirmed an increase up to 10,000 ppm and drastically declined beyond this concentration. Sea Dwarf paspalum and Sea Isle 2000 maintained uniformity in the proline level at all levels of salinity without significant variation. These findings point to the fact that both paspalum and bermuda types exhibited varied responses to different physiological and biochemical parameters under the saline conditions. Paspalum types have an edge over the bermudagrass in terms of shoot density, which is a potential factor in determining the high-quality turfs. Bermudagrass types can be applied in lower salinity conditions based on the responses as evidenced from the present results.