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Protocols to evaluate turfgrass quality rely on visual ratings that, depending on the rater's expertise, can be subjective and susceptible to positive and negative drifts. We developed seasonal (spring, summer and fall) as well as inter-seasonal machine learning predictive models of turfgrass quality using multispectral and thermal imagery collected using unmanned aerial vehicles for two years as a proof-of-concept. We chose ordinal regression to develop the models instead of conventional classification to account for the ranked nature of the turfgrass quality assessments. We implemented a fuzzy correction of the resulting confusion matrices to ameliorate the probable drift of the field-based visual ratings. The best seasonal predictions were rendered by the fall (multi-class AUC: 0.774, original kappa 0.139, corrected kappa: 0.707) model. However, the best overall predictions were obtained when observation across seasons and years were used for model fitting (multi-class AUC: 0.872, original kappa 0.365, corrected kappa: 0.872), clearly highlighting the need to integrate inter-seasonal variability to enhance models' accuracies. Vegetation indices such as the NDVI, GNDVI, RVI, CGI and the thermal band can render as much information as a full array of predictors. Our protocol for modeling turfgrass quality can be followed to develop a library of predictive models that can be used in different settings where turfgrass quality ratings are needed. [ABSTRACT FROM AUTHOR]

Irrigation practices that conserve water use have the potential to reduce greenhouse gas (GHG) emissions but may adversely affect turfgrass appearance. The purpose of this study was to identify irrigation practices and N fertilizers that will decrease carbon dioxide (CO2), methane (CH4,), and nitrous oxide (N2O) emissions while evaluating turfgrass color and quality. In both years, supplemental rainfall (SRF) soil moisture content was higher than business as usual (BAU) irrigation and syringing (SYR). Higher soil moisture led to increased fluxes in both soil CO2 and soil N2O. In 2017, the SRF fluxed lower soil CO2 as soil moisture reached levels that restricted respiration. Soil moisture was also an important predictor of soil N2O flux with BAU and SRF having higher soil N2O fluxes. SRF produced the greenest turf from May to July, whereas SRY and SRF produced the greenest turf from August to October in 2016. Both BAU and SRF had the greenest turf in 2017. BAU had the highest turfgrass quality ratings in 2016 followed by SRF and SRY, respectively, whereas in 2017 SRF and SRY had higher turfgrass quality ratings. When adopting water conservation practices to reduce GHG emissions, soil moisture content and site-specific rainfall should be closely monitored to prevent overwatering. [ABSTRACT FROM AUTHOR]

Greenhouse gas (GHG) emissions are known to contribute to global climate change. A two-year field study on Kentucky bluegrass (Poa pratensis L.) evaluated cultivation practices and fertilizer use on GHGs. The presence of urea and hollow-tine aerification resulted in the highest soil carbon dioxide (CO2) emissions. No significant differences between soil methane (CH4) flux were observed based on fertilizer; however, in 2014 the verticutting cultivation treatment fluxed significantly more soil CH4 than the uncultivated control. Results showed no significant differences in soil nitrous oxide (N2O) in 2013; however, in 2014, both fertilizer and cultivation practices showed significant differences between treatments, with the urea and the hollow-tine treatments fluxing significantly more soil N2O. The hollow-tined plots produced the greenest turf in 2013, followed by the uncultivated control and the verticutted treatment. In 2014, both the hollow-tine and the uncultivated control produced the greenest turf, followed by the verticutted treatment. The hollow-tined and uncultivated control treatments had significantly higher turfgrass quality than the verticutted treatment. The verticutted urea treatment was above acceptable levels (>6.0) for turfgrass quality following all cultivation events. The results show cultivation practices can be identified that reduce GHG emissions while maintaining turfgrass quality and color. [ABSTRACT FROM AUTHOR]

Protocols to evaluate turfgrass quality rely on visual ratings that, depending on the rater’s expertise, can be subjective and susceptible to positive and negative drifts. We developed seasonal (spring, summer and fall) as well as inter-seasonal machine learning predictive models of turfgrass quality using multispectral and thermal imagery collected using unmanned aerial vehicles for two years as a proof-of-concept. We chose ordinal regression to develop the models instead of conventional classification to account for the ranked nature of the turfgrass quality assessments. We implemented a fuzzy correction of the resulting confusion matrices to ameliorate the probable drift of the field-based visual ratings. The best seasonal predictions were rendered by the fall (multi-class AUC: 0.774, original kappa 0.139, corrected kappa: 0.707) model. However, the best overall predictions were obtained when observation across seasons and years were used for model fitting (multi-class AUC: 0.872, original kappa 0.365, corrected kappa: 0.872), clearly highlighting the need to integrate inter-seasonal variability to enhance models’ accuracies. Vegetation indices such as the NDVI, GNDVI, RVI, CGI and the thermal band can render as much information as a full array of predictors. Our protocol for modeling turfgrass quality can be followed to develop a library of predictive models that can be used in different settings where turfgrass quality ratings are needed.

Turfgrass managers have suspected that runoff-independent movement of herbicides and fertilizers is partially responsible for uneven turfgrass quality in sloped areas. We hypothesized that subsurface lateral solute transport might explain this phenomenon especially in areas with abrupt textural changes between surface and subsurface horizons. A study was conducted to track solute transport using bromide (Br−), a conservative tracer, as a proxy of turfgrass soil inputs. Field data confirmed the subsurface lateral movement of Br− following the soil slope direction, which advanced along the boundary between soil horizons over time. A model based on field data indicated that subsurface lateral movement is a mechanism that can transport fertilizers and herbicides away from the application area after they have been incorporated within the soil, and those solutes could accumulate and resurface downslope. Our results demonstrate that subsurface lateral transport of solutes, commonly ignored in risk assessment, can be an important process for off-target movement of fertilizers and pesticides within soils and turfgrass systems in sloped urban and recreational landscapes. [ABSTRACT FROM AUTHOR]

Plant growth regulators (PGRs) are widely used in turfgrass management. This study aimed to find the influence of different rates of PGRs on Kentucky bluegrass visual quality. Six PGRs were applied, Trinexapac Ethyl, Paclobutrazol, Flurprimidol, Mefluidide, Ethephon, and Gibberellic Acid. The measurement of the leaf color was performed using a spectrophotometer. The turfgrass visual quality was judged using a visual rating system. Trinexapac Ethyl and Flurprimidol applications improved the overall appearance of turfgrass. Paclobutrazol and Gibberellic Acid decreased the overall appearance of investigated Kentucky bluegrass cultivars. The leaf texture assessment was only improved by Gibberellic Acid. The color assessment was enhanced with Paclobutrazol but deteriorated with Gibberellic Acid. PGRs affected the wavelength in a range of 520 to 630 nm. Gibberellic Acid caused lighter leaves with higher green and yellow hues. Paclobutrazol caused darker leaves with a lower green and a reddish hue. Trinexapac Ethyl application resulted in a more reddish hue. PGR rates also affected the visual quality of Kentucky bluegrass turfgrass. [ABSTRACT FROM AUTHOR]

Previous research involving turfgrass response to soil moisture used methodology that may compromise root morphology or fail to control outside environmental factors. Water-table depth gradient tanks were employed in the greenhouse to identify habitat specialization of hybrid bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt-Davy] and manilagrass [Zoysia matrella (L.) Merr.] maintained at 2.5 and 5.1 cm. Turfgrass quality (TQ), normalized difference vegetation index (NDVI), canopy temperature (CT), and root biomass (RB) were used as metrics for plants grown in monoculture in sandy clay loam soil. Mowing height did not affect growth of turfgrass species in response to soil moisture. Turfgrass quality, NDVI, and RB were greatest, whereas CT was lowest at wetter levels [27- to 58-cm depth to the water-table (DWT)] of each tank where plants were growing at or above field capacity. However, bermudagrass RB was greatest at 27-cm DWT, whereas manilagrass RB at 27-cm DWT was lower than RB at 42.5- to 73.5-cm DWT in 2013 and lower than all other levels in 2014. Both species responded similarly to droughty levels (120- to 151-cm DWT) of the tanks. Turfgrass quality, NDVI, and RB were lowest, whereas CT was highest at higher droughty levels. Bermudagrass may be more competitive than manilagrass when soil moisture is high whereas both species are less competitive when soil moisture is low.

The incorporation of biostimulants, including microbial inoculants, into turfgrass management programs has increased during the past decade as a result of the potential benefits of their use, including increased nutrient uptake, enhanced growth, and improved stress tolerance. However, minimal research has been conducted on warm-season grasses, and questions still exist regarding microbial inoculant application timing, frequency of inoculation, and need for supplemental nitrogen. Therefore, the objective of our research was to investigate the influence of nitrogen fertilizer and microbial inoculant application timings on the establishment of common bermudagrass [Cynodon dactylon (L.) Pers.] in the field and in a controlled environment. Treatments containing fertilizer had a consistently greater normalized difference vegetation index, turfgrass color, and turfgrass quality than treatments that contained only the Klebsiella variicola microbial inoculant (KV). Establishment of bermudagrass plots in response to treatments containing fertilizer had more than 90% cover at the conclusion of the study (8 weeks after seeding), whereas KV treatments and the untreated check never exceeded 70% cover. However, the greatest change in carbon efflux was often observed in the field in response to treatments that supplied KV 3 weeks after seeding. In the greenhouse, the greatest root and shoot weights were typically observed in response to treatments containing fertilizer, whereas KV-alone treatments resulted in root and shoot weights either similar to or less than the untreated check.

Plant growth regulators (PGRs) are widely used in turfgrass management. This study aimed to find the influence of different rates of PGRs on Kentucky bluegrass visual quality. Six PGRs were applied, Trinexapac Ethyl, Paclobutrazol, Flurprimidol, Mefluidide, Ethephon, and Gibberellic Acid. The measurement of the leaf color was performed using a spectrophotometer. The turfgrass visual quality was judged using a visual rating system. Trinexapac Ethyl and Flurprimidol applications improved the overall appearance of turfgrass. Paclobutrazol and Gibberellic Acid decreased the overall appearance of investigated Kentucky bluegrass cultivars. The leaf texture assessment was only improved by Gibberellic Acid. The color assessment was enhanced with Paclobutrazol but deteriorated with Gibberellic Acid. PGRs affected the wavelength in a range of 520 to 630 nm. Gibberellic Acid caused lighter leaves with higher green and yellow hues. Paclobutrazol caused darker leaves with a lower green and a reddish hue. Trinexapac Ethyl application resulted in a more reddish hue. PGR rates also affected the visual quality of Kentucky bluegrass turfgrass.

Turfgrass managers have suspected that runoff-independent movement of herbicides and fertilizers is partially responsible for uneven turfgrass quality in sloped areas. We hypothesized that subsurface lateral solute transport might explain this phenomenon especially in areas with abrupt textural changes between surface and subsurface horizons. A study was conducted to track solute transport using bromide (Br−), a conservative tracer, as a proxy of turfgrass soil inputs. Field data confirmed the subsurface lateral movement of Br− following the soil slope direction, which advanced along the boundary between soil horizons over time. A model based on field data indicated that subsurface lateral movement is a mechanism that can transport fertilizers and herbicides away from the application area after they have been incorporated within the soil, and those solutes could accumulate and resurface downslope. Our results demonstrate that subsurface lateral transport of solutes, commonly ignored in risk assessment, can be an important process for off-target movement of fertilizers and pesticides within soils and turfgrass systems in sloped urban and recreational landscapes.

Previous research involving turfgrass response to soil moisture used methodology that may compromise root morphology or fail to control outside environmental factors. Water-table depth gradient tanks were employed in the greenhouse to identify habitat specialization of hybrid bermudagrass [Cynodon dactylon (L.) Pers. 3 C. transvaalensis Burtt-Davy] and manilagrass [Zoysia matrella (L.) Merr.] maintained at 2.5 and 5.1 cm. Turfgrass quality (TQ), normalized difference vegetation index (NDVI), canopy temperature (CT), and root biomass (RB) were used as metrics for plants grown in monoculture in sandy clay loam soil. Mowing height did not affect growth of turfgrass species in response to soil moisture. Turfgrass quality, NDVI, and RB were greatest, whereas CT was lowest at wetter levels [27- to 58-cm depth to the water-table (DWT)] of each tank where plants were growing at or above field capacity. However, bermudagrass RB was greatest at 27-cm DWT, whereas manilagrass RB at 27-cm DWT was lower than RB at 42.5- to 73.5-cm DWT in 2013 and lower than all other levels in 2014. Both species responded similarly to droughty levels (120- to 151-cm DWT) of the tanks. Turfgrass quality, NDVI, and RB were lowest, whereas CT was highest at higher droughty levels. Bermudagrass may be more competitive than manilagrass when soil moisture is high whereas both species are less competitive when soil moisture is low. [ABSTRACT FROM AUTHOR]

Application[Editor 321] of biotic growth regulators (e.g. humic components) and appropriate mulches is recommended to improve turfgrass quality especially in arid andsemi-arid climate zones. However, limited number of studies have investigated their effect on lawn establishment. To investigate the effect of humic acid (HA) and selected mulches on characteristics of Festuca arundinacea in its planting stage, a factorial experiment based on a completely randomized block design with three replications was performed. The first factor was mulch types including vermicompost, leaf compost, cow manure,[Editor 322] and sand (control) which were used to cover the seeds. The second factor was a HA solution (100 ml l-1) sprayed monthly over the period of the experiment. Plant height, fresh and dry weight of lawn clippings, photosynthetic index, leaf texture, and overall turfgrass quality were measured. Spraying HA significantly improved the measured factors except the dry weight and photosynthetic index of the plants. Among the mulches, vermicompost provided better impressions on improving the characteristics of this turfgrass species including 48% increase in fresh weight, 18% increase in height, 48% increase in total quality, and 10% reduction in leaf width of the turfgrass. This research can assist in developing knowledge for having high quality lawns in urban landscapes of arid and semi-arid environments.

Continuous monoculture of cool-season turfgrass causes soil degradation, and visual turf quality decline is a major concern in black soil regions of Northeast China. Turf mixtures can enhance turfgrass resistance to biotic and abiotic stresses and increase soil microbial diversity. Understanding mechanism by plant-soil interactions and changes of black soil microbial communities in turf mixture is beneficial to restoring the degradation of urbanized black soils and maintaining sustainable development of urban landscape ecology. In this study, based on the previous research of different sowing models, two schemes of turf monoculture and mixture were conducted in field plots during 2016–2018 in a black soil of Heilongjiang province of Northeast China. The mixture turf was established by mixing 50% Kentucky bluegrass “Midnight” (Poa pratensis L.) with 50% Red fescue “Frigg” (Festuca rubra L.); and the monoculture turf was established by sowing with pure Kentucky bluegrass. Turf performance, soil physiochemical properties, and microbial composition from rhizosphere were investigated. Soil microbial communities and abundance were analyzed by Illumina MiSeq sequencing and quantitative PCR methods. Results showed that turfgrass quality, turfgrass biomass, soil organic matter (SOM), urease, alkaline phosphatase, invertase, and catalase activities increased in PF mixture, but disease percentage and soil pH decreased. The microbial diversity was also significantly enhanced under turf mixture model. The microbial community compositions were significantly different between the two schemes. Turf mixtures obviously increased the abundances of Beauveria, Lysobacter, Chryseolinea, and Gemmatimonas spp., while remarkably reduced the abundances of Myrothecium and Epicoccum spp. Redundancy analysis showed that the compositions of bacteria and fungi were related to edaphic parameters, such as SOM, pH, and enzyme activities. Since the increasing of turf quality, biomass, and disease resistance were highly correlated with the changes of soil physiochemical parameters and microbial communities in turf mixture, which suggested that turf mixture with two species (i.e., Kentucky blue grass and Red fescue) changed soil microbial communities and enhanced visual turfgrass qualities through positive plant-soil interactions by soil biota.

Continuous monoculture of cool-season turfgrass causes soil degradation, and visual turf quality decline is a major concern in black soil regions of Northeast China. Turf mixtures can enhance turfgrass resistance to biotic and abiotic stresses and increase soil microbial diversity. Understanding mechanism by plant-soil interactions and changes of black soil microbial communities in turf mixture is beneficial to restoring the degradation of urbanized black soils and maintaining sustainable development of urban landscape ecology. In this study, based on the previous research of different sowing models, two schemes of turf monoculture and mixture were conducted in field plots during 2016–2018 in a black soil of Heilongjiang province of Northeast China. The mixture turf was established by mixing 50% Kentucky bluegrass "Midnight" (Poa pratensis L.) with 50% Red fescue "Frigg" (Festuca rubra L.); and the monoculture turf was established by sowing with pure Kentucky bluegrass. Turf performance, soil physiochemical properties, and microbial composition from rhizosphere were investigated. Soil microbial communities and abundance were analyzed by Illumina MiSeq sequencing and quantitative PCR methods. Results showed that turfgrass quality, turfgrass biomass, soil organic matter (SOM), urease, alkaline phosphatase, invertase, and catalase activities increased in PF mixture, but disease percentage and soil pH decreased. The microbial diversity was also significantly enhanced under turf mixture model. The microbial community compositions were significantly different between the two schemes. Turf mixtures obviously increased the abundances of Beauveria , Lysobacter , Chryseolinea , and Gemmatimonas spp., while remarkably reduced the abundances of Myrothecium and Epicoccum spp. Redundancy analysis showed that the compositions of bacteria and fungi were related to edaphic parameters, such as SOM, pH, and enzyme activities. Since the increasing of turf quality, biomass, and disease resistance were highly correlated with the changes of soil physiochemical parameters and microbial communities in turf mixture, which suggested that turf mixture with two species (i.e., Kentucky blue grass and Red fescue) changed soil microbial communities and enhanced visual turfgrass qualities through positive plant-soil interactions by soil biota. [ABSTRACT FROM AUTHOR]

The need for water conservation continues to increase as global freshwater resources dwindle. Turfgrass mangers are adapting to these concerns by implementing new tools to reduce water consumption. Time-domain reflectometer (TDR) soil moisture sensors can decrease water usage when scheduling irrigation, but nonuniformity across unsampled locations creates irrigation inefficiencies. Remote sensing data have been used to estimate soil moisture stress in turfgrass systems through the normalized difference vegetation index (NDVI). However, numerous stressors other than moisture constraints impact NDVI values. The water band index (WBI) is an alternative index that uses narrowband, near-infrared light reflectance to estimate moisture limitations within the plant canopy. The green-to-red ratio index (GRI) is a vegetation index that has been proposed as a cheaper alternative to WBI as it can be measured using digital values of visible light instead of relying on more costly hyperspectral reflectance measurements. A replicated 2 × 3 factorial experimental design was used to repeatedly measure turf canopy reflectance and soil moisture over time as soils dried. Pots of ‘007’ creeping bentgrass (CBG) and ‘Latitude 36’ hybrid bermudagrass (HBG) were grown on three soil textures: United States Golf Association (USGA) 90:10 sand, loam, and clay. Reflectance data were collected hourly between 07:00 and 19:00 using a hyperspectral radiometer and volumetric water content (VWC) data were collected continuously using an embedded soil moisture sensor from soil saturation until complete turf necrosis by drought stress. The WBI had the strongest relationship to VWC (r = 0.62) compared to GRI (r = 0.56) and NDVI (r = 0.47). The WBI and GRI identified significant moisture stress approximately 28 h earlier than NDVI (p = 0.0010). Those metrics also predicted moisture stress prior to fifty percent visual estimation of wilt (p = 0.0317), with lead times of 12 h (WBI) and 9 h (GRI). By contrast, NDVI provided 2 h of prediction time. Nonlinear regression analysis showed that WBI and GRI can be useful for predicting moisture stress of CBG and HBG grown on three different soil textures in a controlled environment.

Annual bluegrass (ABG) (Poa annua L.) is a prolific seed producer in the spring on golf courses that in turn decreases aesthetic quality and trueness of ball roll on coolseason putting greens. Proxy (ethephon) applied twice in the spring after green-up is the current industry standard after the loss of Embark (mefluidide) from the turf and ornamental market. However, plant growth regulators including Proxy have been used for years to help suppressABGseedheads with inconsistent success. The primary objective of this study was to determine if ABG seedhead suppression is improved by adding a late fall application of Proxy to the two traditional spring applications of plant growth regulators at nine locations with diverse environments. Asecond objectivewas to determine the importance of including Primo Maxx (trinexapac-ethyl) in fall and spring applications. Adding a late fall application of Proxy prior to the two spring applications (F+S+S) improved control of ABG seedheads over the traditional two spring applications (S+S), but themagnitude of improvement varied among locations. When treatments were applied F+S+S, the industry standard tank mixture of Proxy + Primo Maxx provided consistent ABG seedhead control and turf quality, similar to Proxy + Fiata (phosphonate + proprietary pigment) and equal to or better than Proxy alone. [ABSTRACT FROM AUTHOR]

Salinity stress is one of the main problems in turfgrass management. This study was carried out to determine the salinity tolerance of various coolseason turfgrass cultivars (Lolium perenne "Belida", Festuca rubra commutata "Casanova", Poa protensis "Evora" and Festuca rubra trichophylla "Smyrna") by using irrigation waters with different salinity levels. The study was conducted under greenhouse conditions, planting cultivars in plastic pots filled with a mixture of soil, sand, and peat (4:1:1 by volume) as a growing substrate. Then, 6 different irrigation water sources with gradually increased salinity levels [0.54 (T0, control; well water EC value), 25 mM (T1), 50 mM (T2), 100 mM (T3), 150 mM (T4) and 200 mM (T5)] were applied to the turfgrass cultivars. During the experiment, observations and measurements were made on turfgrass quality, clipping yield, chlorophyll content, shoot and root dry weights. As a result, it was determined that Belida (Lolium perenne L.) and Smyrna (Festuca rubra trichophylla) varieties were highly tolerant to salinity stress. [ABSTRACT FROM AUTHOR]

Golf courses in the western United States increasingly are being irrigated with recycled water. Research was conducted on eight golf courses in a semiarid region, including three courses with recycled water irrigation for 10 years, three courses with recycled water irrigation for 18 to 26 years, and two courses with surface water for irrigation for 15 and 18 years. Turf quality of kentucky bluegrass (Poa pratensis) (KBG), the most widely used turfgrass species in the United States, was evaluated on 25 roughs from the aforementioned golf courses. Concurrently, KBG shoot samples and soil samples from these sites were collected. Shoots of KBG were analyzed for mineral concentrations, including sodium (Na), calcium (Ca), magnesium (Mg), potassium (K), chlorine (Cl), boron (B), sulfur (S), phosphorus (P), manganese, iron, zinc, copper, and molybdenum. Electrical conductivity (EC) and sodium absorption ratio (SAR) of soil saturated paste were determined. Recycled water irrigation for 10 and >18 years increased clipping Na by 4.3 and 9.9 times and Cl by 1.5 and 1.3 times, respectively. Compared with surface water irrigation, B concentration in KBG shoots increased by 3.5 times and K concentration reduced by 16% on sites with recycled water irrigation for >18 years. Multiple regression analysis was conducted to identify the relationships between mineral concentration in shoots and turf quality. There was a negative linear relationship between turf quality and Na concentration in the shoots (R² = 0.65). Soil SAR in 0 to 20 cm depth was highly associated with KBG shoot Na, as documented by a logarithmic regression of R² = 0.70. Stepwise regression indicated that Na accumulation in the shoots was the leading plant variable causing the decline of turf quality under recycled water irrigation. Therefore, it is reasonable to believe that water treatment and management practices that can reduce soil SAR and Na concentration in KBG shoots would improve turf quality and plant health. [ABSTRACT FROM AUTHOR]

Summer annual grassy weeds such as goosegrass (Eleusine indica L. Gaertn.) continue to be problematic to control selectively with postemergence (POST) herbicides within turfgrass stands. In recent years, reduced performance by certain herbicides (e.g., foramsulfuron), cancellation of goosegrass-specific herbicides (e.g., diclofop-methyl), and cancellation and/or severe use reductions of other herbicides [e.g., monosodium methanearsonate (MSMA)] have limited the options for satisfactory control and maintenance of an acceptable (£30% visual turfgrass injury) turfgrass quality. Currently available herbicides (e.g., topramezone and metribuzin) with goosegrass activity typically injure warm-season turfgrass species. The objectives of this research were to evaluate both 'Tifway 419' bermudagrass [Cynodon dactylon (L.) Pers. 3Cynodon transvaalensis Burtt-Davy] injury after treatment with POST herbicides, and to determine whether irrigating immediately after application reduces turfgrass injury. Treatments were control (± irrigation); topramezone (Pylex 2.8C; ± irrigation); carfentrazone + 2,4-D + dicamba + 2-(2-methyl-4-chlorophenoxy) propionic acid (MCPP) (Speedzone 2.2L; ± irrigation); carfentrazone + 2,4-D+ dicamba +MCPP in combination with topramezone (± irrigation); metribuzin (Sencor 75DF; ± irrigation); mesotrione (Tenacity 4L; ± irrigation); simazine 4L (±irrigation); and mesotrione + simazine (± irrigation). Irrigated treatments were applied immediately with a hand hose precalibrated to apply 0.6 cm or 0.25 inch ('6.3 L). Visual turfgrass injury for combined herbicide treatments for the irrigated plots was 6% 4 days after treatment (DAT), 12% 1 week after treatment (WAT), 17% 2 WAT, and 6% 4 WAT, whereas nonirrigated plots had turfgrass injury of 14% at 4 DAT, 31% 1 WAT, 35% 2 WAT, and 12% 4 WAT. Irrigated pots had normalized differences vegetative indices (NDVI) ratings of 0.769 at 4 DAT, 0.644 at 1 WAT, 0.612 at 2 WAT, and 0.621 at 4 WAT, whereas nonirrigated plots had the lowest (least green) turfgrass NDVI ratings of 0.734 at 4 DAT, 0.599 at 1 WAT, 0.528 at 2 WAT, and 0.596 at 4 WAT. These experiments suggest turfgrass injury could be alleviated by immediately incorporating herbicides through irrigation. [ABSTRACT FROM AUTHOR]

Application of biotic growth regulators (e.g. humic components) and appropriate mulches is recommended to improve turfgrass quality especially in arid andsemi-arid climate zones. However, limited number of studies have investigated their effect on lawn establishment. To investigate the effect of humic acid (HA) and selected mulches on characteristics of Festuca arundinacea in its planting stage, a factorial experiment based on a completely randomized block design with three replications was performed. The first factor was mulch types including vermicompost, leaf compost, cow manure, and sand (control) which were used to cover the seeds. The second factor was a HA solution (100 ml l-1) sprayed monthly over the period of the experiment. Plant height, fresh and dry weight of lawn clippings, photosynthetic index, leaf texture, and overall turfgrass quality were measured. Spraying HA significantly improved the measured factors except the dry weight and photosynthetic index of the plants. Among the mulches, vermicompost provided better impressions on improving the characteristics of this turfgrass species including 48% increase in fresh weight, 18% increase in height, 48% increase in total quality, and 10% reduction in leaf width of the turfgrass. This research can assist in developing knowledge for having high quality lawns in urban landscapes of arid and semi-arid environments [ABSTRACT FROM AUTHOR]

Core Ideas: Foliar fertilizer treatments did not deplete soil nutrient levels after three years of applications.Combining foliar and granular fertilizers resulted in the best turfgrass quality.Biweekly application of foliar fertilizers resulted in higher turf quality than monthly granular fertilizer applications. Research was conducted to determine the effects of foliar and granular fertilizers on creeping bentgrass [Agrostis stolonifera var. L. palustris (Huds.) Farw. 'Penn A4'] quality and soil nutrient levels of two putting green rootzones. The hypothesis was foliar fertilizers would decrease soil nutrient levels and result in lower turfgrass quality over 3 yr compared to granular fertilizers. The fertilizer treatments were granular urea, methylene urea, and natural organic, foliar fertilizer at two rates, foliar‐granular combination, and an untreated control. The two rootzones were a United States Golf Association (USGA) guideline rootzone and a sandy clay loam (58% sand, 20.5% silt, and 21.5%) native soil. The urea, methylene urea, natural organic, and foliar‐granular treatments were applied at 0.5 lb N/1000 ft2/month from May through October. The foliar treatment was applied at two rates, 0.25 and 0.5 lb N/1000 ft2/month from May through October. Soil samples were collected from 2009 to 2011 and turfgrass quality was rated every 2 weeks. Turfgrass growing on native soil had consistently higher quality than turfgrass on the USGA rootzone and native soil had higher soil NO3–N, P, and K levels than the USGA rootzone. Neither the foliar, granular, or combination treatments decreased soil NO3–N, P, or K levels compared to initial soil test levels over 3 year of research. Every two weeks, applications of both the combination and foliar 2X treatments produced higher turfgrass quality than monthly methylene urea, urea, and organic treatments. Although the 0.25 lb N/1000 ft2/month foliar treatment had a lower N rate than all fertilizer treatments, it had acceptable quality throughout the research. [ABSTRACT FROM AUTHOR]

Drought avoidance is dictated by a collection of traits used to maintain tissue hydration levels and turgidity during water-limited conditions. These traits include deeper and more extensive rooting and the closure of stomata to limit the transpiration of water from leaves. Zoysiagrasses are a group of warm-season turfgrasses, including Zoysia japonica and Zoysia matrella, that are valued for their turfgrass quality; however, they are susceptible to drought relative to other warm-season turfgrass species. The objectives of the study were to determine 1) differences in drought avoidance among a collection of zoysiagrasses and 2) which drought avoidance traits contributed to these differences. Fifteen zoysiagrass genotypes were exposed to either drought or control conditions in a greenhouse environment. Overall performance was assessed by evaluating turfgrass quality and percentage green cover. Drought avoidance was estimated by measuring leaf hydration levels and drought avoidance traits [including stomatal conductance (gS)]; root traits such as total root biomass, specific root length (SRL), and root length density (RLD) were measured. Compared with commercial cultivars Meyer, Palisades, or Zeon, some experimental genotypes maintained greater turfgrass quality during drought, with experimental genotype '09-TZ-54-9' having a quality rating of 7.8 after 20 days of drought compared with 5.3 in 'Zeon', 5.2 in 'Meyer', and 5.0 in 'Palisades'. A range of belowground traits such as root biomass was also found to be associated with drought avoidance, with experimental '09-TZ-53-20' having 1.03 total grams, and 2.39 total grams in '10-TZ-1254', compared with 1.14, 1.66, and 3.44 total grams in 'Meyer', 'Zeon', and 'Palisades', respectively. Significant differences in drought avoidance were found among the 15 genotypes, with both belowground rooting traits and aboveground factors affecting transpiration influencing plant performance. [ABSTRACT FROM AUTHOR]

Shading of golf course putting greens often reduces turf quality (TQ). Observations suggested velvet bentgrass (Agrostis canina L., VBG) was more shade tolerant than creeping bentgrass (A. stolonifera L., CBG). Our objectives were to compare the TQ and growth response of 'Vesper' VBG and 'Tyee' CBG to N rates and growth regulator application under 80% shade. The experimental design was a randomized block, strip-split plot with four replications. Foliar urea N was applied every 14 d at annual N rates of 49, 98, and 196 kg ha-1. Trinexapac-ethyl (TE, 0.00 and 0.05 kg a.i. ha-1) was applied every 28 d. Treatments were applied May through October 2009 and 2010. Data collected were TQ, clipping yield, relative chlorophyll index (RCI), and ball roll distance. Nitrogen rate affected TQ more than TE application, though effects of both factors were significant in both years. Turf quality differences between species only affected TQ in 2010 when CBG had higher TQ than VBG on 9 of 19 dates. Rating date and N rate accounted for most clipping yield differences. In 2009, VBG had less clipping yield than CBG. Differences in RCI were greatest in 2010, with 196 kg ha-1 N having significantly lower RCIs than the other N rates when compared across rating dates. Nitrogen rate and species each affected ball roll distances. Neither VBG nor CBG provided acceptable putting green TQ at 80% shade. Application of TE and 49 kg ha-1 yr-1 N resulted in the highest TQ for the longest duration. [ABSTRACT FROM AUTHOR]

Abstract: In recent years, rising competition for water coupled with new environmental regulations has exerted pressure on water allocations for turfgrass irrigation. In this article, we reviewed published scientific and industry evidence on the agronomic and environmental impacts of turfgrass irrigation using a robust systematic review methodology. Our focus was on the links between (i) irrigation management (amount and frequency), (ii) agronomic responses to irrigation (turf quality, growth rates and rooting) and (iii) environmental impacts (nitrogen leaching). Based on an initial screening of 653 studies and data extracted from 83 papers, our results show that in most cases, under moderate levels of deficit irrigation (50%–60% of actual evapotranspiration), turf quality can be maintained at an acceptable level but with lower water consumption compared to irrigating back to field capacity. Irrigation beyond field capacity was found to increase the risk of nutrient leaching. However, evidence also showed that the concentration and total loss of NO 3 − in leachate were influenced more by nitrogen (N) rates, soil characteristics, turfgrass species and turfgrass growth rates than by irrigation practices. Our analyses suggest that turfgrass irrigation should be scheduled to apply water at moderate levels of deficit irrigation, sufficient to maintain turfgrass quality but limited to promote a deep and extensive rooting system. The findings provide new insights and valuable evidence for both scientists and practitioners involved in turfgrass research and management. [ABSTRACT FROM AUTHOR]

Abstract: Conversion from annual bluegrass or bentgrasses to red fescue could be an efficient way to minimise water use on golf greens. Our objective was to investigate the influences of four irrigation strategies on red fescue water use efficiency, turf quality, growth rate and resistance to annual bluegrass and moss invasion. The trial was carried out from August 2013 to August 2015 on a green established according to USGA recommendations under a rainout shelter at Landvik, Norway (58 °N). On average for 2 years, irrigation to field capacity once per week (FC 1) and deficit irrigation to 60% of FC three times per week (DEF 3) reduced the water consumption by 49% and 72% relative to irrigation to FC three times per week (FC 3). Both DEF 3 and FC 1 retained acceptable turf quality and reduced annual bluegrass in the second year by about one‐third. Better control of annual bluegrass was obtained with deficit irrigation to 60% of FC once per week (DEF 1), but this treatment did not produce acceptable turf quality. Compared with FC 3, DEF 3, FC 1 and DEF 1 gave harder surfaces and reduced the moss invasion in the second year by 66%, 90% and 93%, respectively. Irrigation effects on root development and thatch organic matter after 2 years were not significant, although the thatch layer depth was 3–4 mm greater in FC 1 than in the other treatments. In conclusion, DEF 3 and FC 1 are both effective irrigation strategies for managing red fescue greens with less water use. [ABSTRACT FROM AUTHOR]

The current study was conducted to investigate the influence of different seed sowing rates 5, 10, 15, 20 and 25 g m-2 and five cutting times (T1:15 June, T2: 15 July, T3:15 August, T4: 15 September and T5:15 October 2013) on yield and the quality characteristics of Kentucky bluegrass (Poa pratensis L. cv. Geronimo). The experiment was carried out in a Completely Randomised Block Design with three replications. The experiment was conducted at the Agricultural Application and Research Centre of Iğdır University in 2013. The investigated characters were measured, the covering rate, green grass yield, the plant height, colour, leaf width and turfgrass quality in the trial. The results indicated that 5, 10, 15, 20 and 25 of seed density per m-2 produced covering rate 8.5, 22.7, 49.6, 51.8 and 57.0 (%); green grass yield 83.3, 218.7, 415.3, 457.3 and 514.0 g m-2; plant height 7.9, 7.9, 8.4,8.6 and 8.3 cm; color 5.6, 5.6, 5.9, 5.9 and 6.0 (1-9 scala); leaf size 1.13, 1.19, 1.12, 1.14 and 1.14 mm; turf grass quality ranged from 1.19, 3.07, 4.93, 5.42 and 5.50 (1-9 scala). Under the environment conditions of Igdır, the highest green yield of grass, coverage ratio, colour and turfgrass quality were achieved by the application of 25 g seeds per m-2. In respect of cutting times, the highest green yield and coverage rate were produced at T5 time, as well as the highest colour at T5, T1 and T2 times, respectively and turf grass quality was obtained at T5 and T4 times in the application of 25 g seeds per m2 during the establishing year. Accordingly, it can be concluded that the rates of seed to be recommended in 25 g per square, when all the features examined are taken into account of Poa grown in landscape establishment under the Iğdır ecological conditions. [ABSTRACT FROM AUTHOR]

The article discusses the use of trait prioritization in the breeding of turfgrass. Topics include the selection of traits by turfgrass breeders and distributors, the impacts of consumer attitudes and marketing companies on the selection of traits, and regional and gender differences in trait selection priorities.

The article discusses research on U.S. and Canadian consumer preferences for turfgrass, noting possible market segmentation. Topics include the views of consumers regarding maintenance attributes, the opportunity for greater production of low-input species by the turfgrass seed industry, and generational differences among turfgrass consumers.

The positive effects of trinexapac-ethyl (TE) on turfgrass growth and tolerance to various types of stress could promote its use in low-input maintenance turfgrasses to reduce the expense associated with mowing. However, there is a general lack of information about TE effects in low maintenance turfgrasses, and especially when used in transition zone turfgrass mixtures. The objective of this study was to evaluate the response of three inter-specific turfgrass mixtures to three different application rates of TE under low maintenance conditions. A 2-year field study was conducted from April 2006 to July 2008 at the Agricultural Experimental Farm of the University of Padova (northern Italy, 45°20′N, 11°57′E, elevation 8 m). Visual turfgrass quality (1–9 scale) and clippings biomass production of three mixtures were evaluated seasonally under four TE treatments with rates representing 0, 0.5, 1.0 or 1.5x the rates indicated on label instructions. Based on both visual quality and biomass production, turfgrass responded differently to TE application depending on dominant species in the mixture. Furthermore, our results suggested that changes over time in turfgrass botanical composition influence visual quality and biomass production through the experimental period. The main effect of TE treatments occurred in biomass production while the effect on turfgrass quality was mainly associated with the two highest TE rates. Application at a rate lower than the labeled seems to be enough for reducing biomass production without affecting turfgrass quality or even, in some seasons, improving it. Finally, we found that the effect of TE seems to weaken over time as turfgrass maturity advances. [ABSTRACT FROM AUTHOR]

Constructed wetlands (CWs) represent low-cost technology for the treatment and reuse of wastewater in urban areas. This study aimed to evaluate the pollutant removal efficiency of a CW system and to assess the effects of irrigation using treated urban wastewater on soil and on two warm-season turf species. The research was carried out in Sicily (Italy) on a pilot-scale horizontal subsurface flow system which was fed with treated urban wastewater following secondary treatment from an activated-sludge wastewater treatment plant. The pilot system was located in an open urban park and comprised two separate parallel planted units. Experimental fields of Cynodon dactylon (L.) Pers. and Paspalum vaginatum Sw. were set up close to the system and irrigated with both treated wastewater (TWW) and freshwater (FW). Irrigation with TWW did not result in a significant variation in soil pH and soil salinity in the topsoil. The turf species tolerated high sodium levels in the soil due to TWW irrigation. Savings in FW and mineral fertilizers were deemed significant. The results highlight the fact that use of CW systems for the treatment and reuse of wastewater can represent a sustainable way to obtain alternative water resources for turfgrass irrigation in urban areas. [ABSTRACT FROM AUTHOR]

Cyanobacteria compete with putting green turf, resulting in algal surface crusts that can reduce turf density and quality. The objectives of this study were to assess preventive control of surface cyanobacteria colonization of putting green turf with various phosphite salt sources and formulations. An optimal rate of phosphorous acid to suppress cyanobacteria while minimizing phytotoxicity was also examined. Two field studies were conducted concurrently on an 'L-93' creeping bentgrass (Agrostis stolonifera L.) putting green in Storrs, CT, during 2010 and 2011. Study 1 assessed various commercial formulations and sources of phosphite salts, potassium phosphate, and non-phosphonate fungicides on percent plot area infested by algae. Study 2 identified rates of phosphorous or phosphoric acid applied as commercial formulations of potassium phosphite or technical preparations of potassium phosphite and phosphate, which reduce or enhance algae development and turf quality. Potassium phosphite reduced percent plot area infested by 90 to 100% and 52 to 86% compared with potassium phosphate in study 1 during 2010 and 2011, respectively. Few differences in plot area infested were observed among six commercial phosphite formulations and sources or non-phosphonate fungicides throughout study 1. Area under the algae development curve decreased by 52 to 78% as phosphorous acid increased from 2.9 to 5.4 or 8.1 kg ha-1 throughout the 2-yr study. Turf quality was reduced in phosphorous acid-treated plots at rates greater than 10.8 kg ha-1. Phosphite products applied at 5.4 to 8.1 kg ha-1 every 14 d can be used to suppress cyanobacteria with reduced risk of phytotoxicity for putting green turf. [ABSTRACT FROM AUTHOR]

Plant growth regulators have been used to improve turfgrass quality and drought tolerance. This study was designed to investigate if foliar application of auxin (indole-3-butyric acid [IBA] at 2 mM) and trinexapac-ethyl (TE, 45 g ha-1), alone or in a combination, improves creeping bentgrass (Agrostis stolonifera L.) root growth and hormone metabolism under water-deficit conditions. The plants were subjected to well-watered or water-deficit stress (40-50% evapotranspiration replacement) conditions for up to 42 d in growth chambers. Water deficit reduced turf quality and net photosynthetic rate (Pn), leaf indole-3-acetic acid (IAA), isopentenyl adenosine (iPA) content, and root viability. Exogenous application of TE or IBA, alone or in a combination, improved turf quality, Pn, and stomatal conductance under water-deficit conditions. Under water deficit, TE, IBA, and TE + IBA treatments also increased leaf IAA, iPA, and abscisic acid content relative to the control. The combination treatment (TE + IBA) increased root biomass relative to the control under waterdeficit and well-watered conditions. Under water deficit, TE, IBA, TE + IBA increased root viability by 16.7, 32.2, and 56.2%, respectively, relative to the control. Under well-watered conditions, IBA, with or without TE, also increased leaf IAA and iPA, as well as root viability. Results suggest that foliar application of auxin and TE at proper rates may promote root viability and hormonally mediated adjustments to drought, resulting in improved turf quality under waterdeficit conditions. [ABSTRACT FROM AUTHOR]

Shade or reduced sunlight poses a major challenge for maintaining acceptable turfgrass quality. The quantification of daily light integral (DLI, mol m-2 d-1) requirement could help to identify shade-tolerant germplasm. The objectives of this study were (i) to compare turf performance, and (ii) to determine seasonal DLI requirement of 12 warm-season turfgrass cultivars in response to varying levels of shade. A greenhouse study that included three experiments was conducted in spring (30/20°C), summer (35/25°C), and winter (25/15°C) months. Shade levels providing 33, 61, and 92% reductions in photosynthetic photo flux were imposed. Twelve cultivars from nine species were evaluated for turfgrass quality (TQ), normalized difference vegetation index, and shoot biomass production over 8 wk. The DLI requirement was obtained through nonlinear regression between DLI and TQ. Most warm-season turfgrass species maintained acceptable TQ up to 33% shade. 'TifGrand' and 'Tifway' bermudagrass [Cynodon dactylon (L.) Pers x C. transvaalensis Burtt-Davy] required each relatively higher DLI ranging from 9.2 (winter) to 21.4 (summer) mol m-2 d-1. Zoysiagrass (Zoysia spp.) cultivars maintained acceptable TQ up to 61% shade, with the lowest DLI requirements ranging from 5.9 (winter) to 10.9 (summer) mol m-2 d-1. The DLI requirements for the tested grasses were lower in winter (5.9-9.9 mol m-2 d-1) than in spring (9.4-17.4 mol m-2 d-1) and summer (9.9-21.4 mol m-2 d-1). 'Argentine' bahiagrass (Paspalum notatum Flugge) had an increased DLI requirement relative to other entries in summer months. [ABSTRACT FROM AUTHOR]

This research was conducted to evaluate turfgrass quality, and coverage rates depend on the seasons in some cool grasses. In the trial, 15 varieties belong to 5 cool season species widely used in landscape areas and sports ground were used. The experiment of the completely randomised design was applied with three replications in 2007-2008. The highest turfgrass quality was obtained from L. perenne Delawery, Ovation varieties and F. rubra trichophylla Suzette in both seasons and years. However, the degree of ground cover of L. perenne Delawery, Ovation varieties and F. rubra trichophylla Dawson variety had the highest according to results of the experiment. In contrary to this, the lowest turfgrass quality was observed from L. perenne Linn and the lowest of ground cover was observed from P. pratensis Balin variety. [ABSTRACT FROM AUTHOR]

A two-year irrigated field study was conducted to determine the effects of plant growth-promoting rhizobacteria (PGPR;Bacillus subtilisOSU-142 andBacillus megateriumM3) as biofertilizer, and in combination with a chemical nitrogen (N) fertilizer, on turf color and clipping yield, and interaction of biofertilizer and chemical N fertilizers in perennial ryegrass (Lolium perenneL.), tall fescue (Festuca arundinaceaL. Schreb.), and Kentucky bluegrass (Poa pratensisL.). The three turf species were tested separately in split-plot design experiments with three replications. Three fertilizer sources (ammonium nitrate only, ammonium nitrate +B. megateriumM3, and ammonium nitrate +B. subtilisOSU-142) were the main plots. N applications with monthly applications of 0.0, 2.5, 5.0, and 7.5 g N/m2were the subplots. Color ratings and clipping yields increased with increasing chemical N fertilizers in all species. Both Bacillus sp. significantly increased color ratings and clipping yields in perennial ryegrass and tall fescue. However, there were no significant differences among the three fertilizer sources in color and clipping yield of Kentucky bluegrass. The experiments showed that there is a small but significant benefit from applying biofertilizers for turf color, and that N fertilization may be reduced in some turf species when biofertilization are made for this purpose. [ABSTRACT FROM AUTHOR]

New elite st. augustinegrass cultivars with improved cold tolerance and desirable turf quality are needed for the turf industry, especially in the transitional climatic region of the United States. To efficiently use sources of cold tolerance in a breeding program, an understanding of the genetic control of this trait and its relationship to important turf quality traits is required. Therefore, the objective of this study was to estimate general and specific combining abilities for cold response and turf quality traits. Six diploid genotypes of st. augustinegrasswere selected as parents for a diallelmating design without reciprocals and evaluated over 3 years at two locations. The true hybridity of crosses was confirmed using simple sequence repeats (SSR). Combining ability analysis revealed that both general and specific combining abilities were significant across years and locations. Specific combining ability (SCA) was the largest source of genetic variation for winter survival, genetic color, turf density, and end-of-season cover indicating that nonadditive gene effects play a key role in the inheritance of these traits. The parental genotype 'GF2' was identified as a promising parent for future breeding efforts as it provided positive general combining ability (GCA) effects for both cold tolerance and turf quality traits, which were not significantly correlated with one another. Lines identified as parental selfs generally showed lower cold response and inferior turf quality than the original parental lines indicating that inbreeding depression can occur in st. augustinegrass. This study provides information regarding the combining ability of cold response and turf quality traits in st. augustinegrass, which will ultimately aid in parental selection for our future breeding efforts. [ABSTRACT FROM AUTHOR]

BACKGROUND Larvae of the Japanese beetle, Popillia japonica (Coleoptera: Scarabaeidae), have a patchy distribution in soils, which complicates detection and management of this insect pest. Managed turf systems are frequently under pest pressure from fungal pathogens, necessitating frequent fungicide applications. It is possible that certain turfgrass fungicides may have lethal or sublethal adverse effects on eggs and larvae of P. japonica that inhabit managed turf systems. In this study, eggs and first-, second- and third-instar larvae were treated with the fungicides chlorothalonil and propiconazole, and survival was compared with that of untreated controls as well as positive controls treated with the insecticide trichlorfon. RESULTS Chlorothalonil reduced survival of first-instar larvae treated directly and hatched from treated eggs. Propiconazole delayed egg hatch, reduced the proportion of eggs that successfully hatched and reduced survival of first-instar larvae treated directly and hatched from treated eggs. Sublethal doses of the fungicides lowered the activities of certain detoxification enzymes in third-instar grubs. CONCLUSIONS Fungicide applications to turfgrass that coincide with oviposition and egg hatch of white grubs may have sublethal effects. This work is applicable both to high-maintenance turfgrass such as golf courses, where applications of pesticides are more frequent, and to home lawn services, where mixtures of multiple pesticides are commonly used. © 2015 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Urban land disturbance degrades physical, chemical, and biological soil properties by removing topsoil and compacting the remaining subsoil. Such practices create a soil environment that is unfavorable for vegetation establishment. A 3-year field study was conducted to compare the effects of various one-time compost application treatments on soil properties and re-vegetation of a disturbed soil. A disturbed urban soil received the following treatments: (1) inorganic fertilizer; (2) 2.5-cm-depth surface-applied compost; (3) 2.5-cm-depth incorporated compost; (4) 5.0-cm-depth incorporated compost; (5) inorganic fertilizer plus 0.6-cm compost blanket; and (6) inorganic fertilizer plus straw mat cover. The plots were seeded with a mixture of tall fescueFestuca arundinaceaShreb.: ‘Magellan,’ ‘Coronado Gold,’ ‘Regiment,’ and ‘Tomcat,’ perennial ryegrassLolium perenneL. ‘Linn’, and Kentucky bluegrassPoa pratenisL. ‘Baron.’ Soil chemical and physical attributes and plant growth and quality parameters were measured during 840 days following study establishment. Soil C, N, P, K, Ca, and Mg, and turfgrass growth and quality were increased and soil bulk density was reduced by amending with composts. Incorporation of compost into soil improved soil and plant attributes more than unincorporated surface application, but the differences diminished with time. Compost benefits increased with time. One-time applications of compost can provide immediate and long-term benefits to soil and plant attributes, but there may be no need to incorporate the compost into soil, particularly if the soil has recently been loosened by tillage. [ABSTRACT FROM AUTHOR]

Developing turfgrass with good drought resistant is a major goal in breeding programs when water scarcity is one of the long-term challenges facing the turfgrass industry. It has been shown that plant transpiration does not decline until available soil water drops below a certain threshold. Studying the species and genotypic differences in this threshold may lead to turfgrass that conserve water and retain turfgrass quality during drought. The objective of this study was to characterize and compare the transpiration response of 19 warm-season turfgrass genotypes and cultivars in five species during soil drying and well-watered conditions in the greenhouse. The species included in the study were: Zoysia japonica (Steud), Zoysia matrella L., common bermudagrass ( Cynodon dactylon L. Pers. var. dactylon ), African bermudagrass ( Cynodon transvaalensis Burtt-Davy), hybrid bermudagrass ( C. dactylon L. var. dactylon × C. translvaalensis Burtt-Davy) and St. Augustinegrass [ Stenotaphrum secundatum (Walter) Kuntze]. They were evaluated for evapotranspiration rate (ET) and the sensitivity of transpiration to soil drying which was indicated by a break point of the fraction transpirable soil water (FTSW). The range of break point during dry down was from 0.25 to 0.41, and genotypes within species had different ET when well-watered (ET ck ). Break point values were not correlated with the number of days to the endpoint, where ET declined below 10% of the control. Instead, the number of days to endpoint was negatively correlated with ET ck (−0.59, P ≤ 0.01). Thus, these results found significant variability in turfgrass break point and ET ck that could contribute to water conservation, and a better understanding of drought responses in warm season turfgrasses. [ABSTRACT FROM AUTHOR]

Creeping bentgrass (Agrostis stolonifera L.) putting greens in the transition zone experience high levels of environmental stress during summer months. The interaction of common management practices combined with foot traffic can exacerbate environmental stress. The objective of this study was to determine the effect of management practices combined with foot traffic during high environmental stress in the transition zone. Creeping bentgrass cultivars, SR 1020 and Penn G2, were managed with various mowing heights (2.5, 3.2, or 4.0 mm), rolling frequencies (0, 3, or 6 d per week), and foot traffic. As environmental stress became prominent during summer months, bentgrass maintained at the lowest mowing heights exhibited poorer turf quality, coverage, and wear tolerance compared to the highest mowing height. SR 1020 quality was reduced below acceptable levels in July when mowed at the lowest mowing height in 2011 and 2012. Penn G2 maintained acceptable quality at all mowing heights in 2011, but severe heat and drought stress reduced turf quality regardless of mowing height in 2012. Daily rolling significantly increased wear on both cultivars during high environmental stress that resulted in decreased turf quality and coverage compared to the nonrolled treatments. The combination of wear from mechanical stress and foot traffic increased wear injury on both cultivars. Under reduced daylengths and optimal air temperatures in September of each year, all response variables improved to similar levels. [ABSTRACT FROM AUTHOR]

Natural plant extracts may alleviate negative effects of abiotic stresses. To test this hypothesis, a field trial was executed to evaluate the effect of natural plant extracts on growth, physiology and quality of Cynodon dactylon under summer stress by following Randomized Complete Block Design (RCBD) having three replicates. When turf established properly, extracts of moringa leaves (3%), seaweed (0.2%), sorghum water (3%), and sunflower water (3%) were foliar applied (two times with an interval of 15 days) while water spray served as control. Results showed that plant extracts had variable but positive effect on tiller height, Inter-nodal distance, leaf area index, root length, root-shoot fresh weight, and root dry weight. However, root-shoot fresh weight ratio and shoot dry weight did not affect significantly by the application of plant extracts under study. Moreover, moringa and seaweed extracts proved most effective equally than sorghum and sunflower extract regarding leaf area index, tiller height, shoot fresh weight and root length. Physiological attributes like chlorophyll contents, cell membrane thermo stability, relative water and K-contents as well as turf quality was also improvd. Conclusively, Moringa oleifera and seaweed extracts can be used to enhance aesthete value of turf by improving its growth and quality. [ABSTRACT FROM AUTHOR]

Adequate turfgrass sod strength for harvesting and handling is typically determined by the producer's past experience and subjective appraisal. This study was conducted to determine the relationship between producer subjective sod-strength assessments and quantitative shear-strength measurements with predominantly kentucky bluegrass (Poa pratensis L.) turf. Across three consecutive growing seasons, 93 samples were collected from sod fields in Rhode Island and assessed for sod strength by subjective and quantitative methods. Producer subjective ratings of sod strength were significantly (P < 0.0001) associated with quantitative measurements of peak force required to shear a sod strip. Minimally acceptable strength occurred most frequently when peak shear force was between 55 and 85 kg⋅m-1 width of sod; whereas preferred sod strength occurred most frequently when peak shear force was between 70 and 140 kg⋅m-1 width of sod. Once peak force exceeded 58 and 86 kg⋅m-1, there was a > 50% probability that sod strength would be judged at least adequate and at preferred strength, respectively, up to a peak force of 140 kg⋅m-1. The results suggest that quantitative measurements of shear strength can be related to producer subjective assessments, and provide unbiased benchmark values to guide management decisions for kentucky bluegrass sod production. [ABSTRACT FROM AUTHOR]

Preemergence (PRE) herbicides negatively impacting turfgrass root growth may compromise macro- and micronutrient accumulation in foliar tissue. Research was conducted to determine the effects of indaziflam (35 and 52.5 g ha−1), prodiamine (0.84 kg ha−1), oxadiazon (3.36 kg ha−1), and isoxaben (1.12 kg ha−1) applications in hydroponic culture on hybrid bermudagrass [C. dactylon(L.) Pers. xC. transvaalensisBurtt-Davy] tissue nutrient content. Prodiamine, indaziflam, and isoxaben reduced visual root mass relative to non-treated plants. Consequently, these herbicides reduced phosphorus (P), sulfur (S), and potassium (K) content in turf foliar tissue. Treatment with indaziflam reduced magnesium (Mg) and manganese (Mn) content in turf foliar tissue compared to non-treated plants. This response was not observed with prodiamine and could explain the significant foliar injury (>70%) observed with both rates of indaziflam. Data in the current study illustrate that PRE herbicide applications affect hybrid bermudagrass nutrient content. Future studies should evaluate foliar applications of Mg and Mn for either preventing or remediating leaf tissue injury following PRE herbicide application. [ABSTRACT FROM AUTHOR]