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Plants are key components of the terrestrial ecosystem carbon cycle. Atmospheric CO2 is assimilated through photosynthesis and stored in plant biomass and in the soil. The use of turfgrass is expanding due to the increasing human population and urbanization. In this review, we summarize recent carbon sequestration research in turfgrass and compare turfgrass systems to other plant systems. The soil organic carbon (SOC) stored in turfgrass systems is comparable to that in other natural and agricultural systems. Turfgrass systems are generally carbon-neutral or carbon sinks, with the exception of intensively managed areas, such as golf course greens and athletic fields. Turfgrass used in other areas, such as golf course fairways and roughs, parks, and home lawns, has the potential to contribute to carbon sequestration if proper management practices are implemented. High management inputs can increase the biomass productivity of turfgrass but do not guarantee higher SOC compared to low management inputs. Additionally, choosing the appropriate turfgrass species that are well adapted to the local climate and tolerant to stresses can maximize CO2 assimilation and biomass productivity, although other factors, such as soil respiration, can considerably affect SOC. Future research is needed to document the complete carbon footprint, as well as to identify best management practices and appropriate turfgrass species to enhance carbon sequestration in turfgrass systems.

Annual bluegrass (AB; Poa annua L.) infestation is aided by phosphorus (P), but there is no information evaluating the effect of P on AB encroachment into turfgrass at seeded establishment. We hypothesized AB seedling survival and vigor will increase with P rates, compromising establishment of desired turfgrass species. Greenhouse pot studies evaluated the effect of P application rate on AB establishment or cover when seeded with perennial ryegrass (Lolium perenne L.) or creeping bentgrass (Agrostis stolonifera L. ‘007’). Two experimental runs were repeated in time. In perennial ryegrass, five P rates (0, 25, 50, 100, and 200 kg P ha−1) and two cultivars (‘Black Cat II’ and ‘Home Run LS’) were tested in sand media (11 mg kg−1 Mehlich‐3 extractable P). In creeping bentgrass, five P rates (0, 12.5, 25, 50, and 100 kg P ha−1), which were modified in the second run (0, 6.25, 12.5, 25, and 50 kg P ha−1), were tested in sand media (3 mg kg−1 Mehlich‐3 extractable P). Regardless of cultivar, AB establishment in perennial ryegrass improved when P was applied and was 90% of maximum at 1.7 kg P ha−1. In creeping bentgrass, both AB and creeping bentgrass cover increased when P was applied and AB was 90% of maximum at 12.1 kg P ha−1. Creeping bentgrass cover was not compromised by P application rates as low as 6.25 kg ha−1. Phosphorus enhances AB cover from seed when sown with perennial ryegrass or creeping bentgrass seed in low P soils. Core Ideas The influence of phosphorus on annual bluegrass competitiveness at seeded establishment is not well understood. Phosphorus fertilization increased annual bluegrass incidence compared with no P in a sand system. Annual bluegrass did not increase in perennial ryegrass if ≥25 kg ha−1 P was applied at seeding. Annual bluegrass cover did not increase in creeping bentgrass if ≥12.5 kg ha−1 P was applied at seeding. Creeping bentgrass is less sensitive to low soil P than annual bluegrass when grown in competition.

Purpose This study aimed at exploring the relationship between intelligence quotient (IQ) and alcohol consumption in a large sample of young males. This study explored whether IQ influences alcohol drinking and which pathways might be involved. We further hypothesized that IQ differences between lifetime abstainers and former drinkers exist, and that they primarily result from different group characteristics. Method Within a psychiatric-epidemiological survey using a cross-sectional design IQ-tests were administered to approximately 50,000 Swiss conscripts at age of about 20 years. The sample was divided into four alcohol consumption categories (rare, occasional, moderate and daily drinking) and two non-drinker categories (former drinking and lifetime abstinence). Probabilities for different levels of consumption or former drinking against lifetime abstention in relation to IQ were estimated using multinomial logistic regression. Models were adjusted for education, disability pension, tobacco/cannabis use, migration, parental alcohol disorders, and mental health. Results After adjusting for confounders full-scale IQ displayed positive associations with being a rare (OR 1.13; CI 95 % 1.07–1.19), occasional (OR 1.41; CI 95 % 1.33–1.48), and moderate drinker (OR 1.53; CI 95 % 1.45–1.62), and negative associations with being a former drinker (OR 0.85; CI 95 % 0.79–0.93). Daily drinking was positively associated only with the performance subscale IQ (OR 1.12; CI 95 % 1.02–1.22). Confounders contributed significantly to the IQ–alcohol association and, therefore, highlight the distinction of non-drinkers into lifetime abstainers and former drinkers. Conclusions Our data confirmed the positive link between IQ and moderate drinking. Lower IQ in non-drinkers, however, seems to be related to earlier consumption and the presence of other risk factors.

The prolific seed production and polyploidy of annual bluegrass allow for the rapid development of herbicide resistance. Ethofumesate-resistant annual bluegrass plants were identified in the 1990s in grass seed production in Oregon, but their prevalence and distribution are not well documented. Therefore a dose–response experiment was initiated to determine the potential level of ethofumesate resistance in seed production systems. Seeds from 55 annual bluegrass populations were obtained from three sources: seed production fields (31 populations), the seed cleaning process (6 populations), and seed testing lots prior to retail distribution (18 populations). Additionally, two populations, one with known ethofumesate resistance and one with known susceptibility, were identified in preliminary testing and used as controls in this experiment. Seed from each collected population was increased. Individual seedlings were then transplanted into separate cone-tainers, grown to a size of 2 to 3 tillers in the greenhouse, and then sprayed using a compressed air track spray chamber with 10 doses of ethofumesate at 0, 0.56, 1.1, 2.8, 5.6, 8.4, 11.2, 16.8, 22.4, and 44.8 kg ai ha-1, with 0.84 to 2.2 kg ha-1 as the label application rate for perennial ryegrass. The resistant to susceptible ratio of populations across all sources ranged from 0.5 to 5.5. The most resistant populations found in production fields, seed cleaning, and seed testing lots had the effective dose necessary to kill 50% of the population (ED50) of 12.1, 9.4, and 13.1 kg ha-1, respectively. Furthermore, 68% of the populations found in production fields had ED50 higher than 6 kg ha-1, indicating common annual bluegrass resistance in grass seed production. As such, growers should implement integrated weed management strategies, as herbicides alone will likely be ineffective at controlling annual bluegrass. Nomenclature: Ethofumesate; annual bluegrass, Poa annua L.; perennial ryegrass, Lolium perenne L.

Core Ideas There is evidence that rolling an annual bluegrass putting green 5 d a wk−1 resulted in a lower severity of Microdochium patch. Two biological control products were shown to significantly lower Microdochium patch severity. Neither biological products nor rolling were shown to completely suppress Microdochium patch; therefore, turfgrass quality was not considered acceptable for any treatments. This study offers evidence of alternative disease control techniques for the management of Microdochium patch on annual bluegrass putting greens. The turfgrass disease Microdochium patch caused by the pathogen Microdochium nivale (Fries) Samuels & I.C. Hallett occurs in cool, humid regions. Fungicide applications are the predominant control method, however increasing pesticide restrictions have generated concern regarding their use. The objective of this research was to evaluate the effects of rolling 5 d wk−1 in combination with three biological control products applied every 2 wk on Microdochium patch severity on an annual bluegrass (Poa annua L.) putting green in the absence of traditional fungicides. Biological control products included; BW136N (Trichoderma harzianum Rifai strain T‐22 + Trichoderma virens (J.H. Mill. Giddens & A.A. Foster) Arx strain G‐41), Rhapsody (Bacillus subtilis strain QST 713), and Provide (a microbial solution containing unspecified strains of Bacillus subtilis, Mucor hiemalis, and Trichoderma harzianum) + ReVive (7% humic acid derived from Leonardite). Rolling was effective at inhibiting Microdochium patch as measured by area under disease progress curves (AUDPC) in both years on rolled plots compared to not rolled plots by 47 and 75%, respectively. Applications of BW136N and Rhapsody reduced the severity of Microdochium patch as measured by AUDPC compared to the control (66 and 50% reduction, respectively). The ProVide + ReVive combination did not suppress disease in this study. At the peak of disease, turfgrass quality was greatest when rolling was combined with applications of BW136N or Rhapsody. These findings suggest that rolling as well as BW136N or Rhapsody can inhibit Microdochium patch severity and further research into this management method is warranted.

Due to complex interactions between social and ecological systems, herbicide resistance has classic features of a “wicked problem”. Herbicide-resistant (HR) Poa annua poses a risk to sustainably managing U.S. turfgrass systems, but there is scant knowledge to guide its management. Six focus groups were conducted throughout the United States to gain understanding of socio-economic barriers to adopting herbicide-resistance management practices. Professionals from major turfgrass sectors (golf courses, sports fields, lawn care, and seed/sod production) were recruited as focus-group participants. Discussions emphasized challenges of the weed management of turfgrass systems as compared to agronomic crops. This included greater time constraints for managing weeds and more limited chemical control options. Lack of understanding about the proper use of compounds with different modes of action was identified as a threat to sustainable weed management. There were significant regional differences in perceptions of the existence, geographic scope, and social and ecological causes of HR in managing Poa annua. Effective resistance management will require tailoring chemical and non-chemical practices to the specific conditions of different turfgrass sectors and regions. Some participants thought it would be helpful to have multi-year resistance management programs that are both sector- and species-specific.

Matrix metalloproteinases contribute to extracellular matrix remodelling that can influence mechanical properties of the vein wall and predispose to varicose veins development. The aim of the study was to assess the following matrix metalloproteinases in the wall of varicose veins: tissue collagenase I (MMP-1), gelatinase A (MMP-2), gelatinase B (MMP-9) and stromelysin 1 (MMP-3). Normal, varicose and varicose veins complicated by thrombophlebitis were collected during the surgical treatment of 26 patients. In harvested tissues the presence of gelatinases was detected with zymography, contents of MMP-1, MMP-2, MMP-3 and MMP-9 were evaluated with ELISA, activity of MMP-1 was assessed with HPLC and activity of MMP-2 with ELISA. Zymography demonstrated particularly high contents of both gelatinases in the wall of varicose veins complicated by thrombophlebitis. The contents of MMP-1, MMP-2 and MMP-9 were significantly increased only in the wall of varicose veins complicated by thrombophlebitis, whereas the increased content of MMP-3 was also found in the wall of varicose veins. A significantly higher activity of MMP-1 was shown only in the wall of varicose veins complicated by thrombophlebitis, whereas an active form of MMP-2 was increased in the wall of varicose, as well as varicose veins complicated by thrombophlebitis, when compared with normal ones. The wall of varicose veins, particularly those complicated by thrombophlebitis shows extensive alterations in the content and activity of matrix metalloproteinases, that may result in extracellular matrix remodelling, influence mechanical properties of the vein wall and predispose to further progression of the disease.

Perceived risk of infection, one factor influencing HIV-related behavior decisions, has been the focus of expanding research efforts. A body of research now exists examining factors related to risk perceptions and the relationship between risk perceptions and behavioral decision making. This article examines 60 quantitative studies of HIV-related risk perceptions, identifies methodological and theoretical limitations or gaps in current knowledge, and suggests ways future research might better assess the role of risk perceptions and facilitate the adoption and maintenance of HIV-related health protective behaviors. The authors argue that mixed findings in the quantitative literature are due to (1) cross-sectional study designs that constrain or confound the interpretation of findings, (2) construct confusion and measurement inconsistencies, (3) insufficient consideration of specific subgroup or behavioral differences, and (4) inattention to situational norms and other contextual factors that influence risk perceptions and behavior.

Traffic simulators are often utilized when researching turfgrass wear tolerance and recovery. However, the availability of a durable traffic simulator capable of producing dynamic force is limited. Therefore, the objectives of this research were to: (i) evaluate a novel traffic simulator with improved durability and capable of producing dynamic force and (ii) evaluate the biophysical effects of the traffic simulator on a native soil turfgrass system. The Baldree traffic simulator is a modified Ryan GA 30 (Jacobsen, A Textron Company, Charlotte, NC) riding aerification unit, equipped with fabricated, spring loaded steel plate feet studded with screw in cleats. The effects of this unit on a ‘Tifway’ bermudagrass [Cynodon dactylon (L.) Pers. × C. transvaalensis Burtt‐Davy] system established on a Tifton loamy sand (fine‐loamy, kaolinitic, thermic Plinthic Kandiudults) were evaluated at the Coastal Plains Experiment Station, Tifton, GA. Factors included location (1 and 2) and traffic rate (0, 12, and 24 passes applied over a 6 wk period). Field data included soil bulk density, turf density, and percent green turf cover. An in‐ground force plate at the McPhail Equine Performance Center, East Lansing, MI was used to quantify vertical and net shear ground reaction force produced by the Baldree traffic simulator when operated in the forward and backward direction. The Baldree traffic simulator produced more cleat marks per pass than the Brinkman and Cady traffic simulators. At the low traffic rate the Baldree traffic simulator increased soil bulk density, while turf density and percent green turf cover decreased; therefore, the tool can be used to simulate heavy traffic conditions with a minimum number of passes.

Hybrid bermudagrasses ( Cynodon dactylon × C. transvaalensis ) typically have excellent wear tolerance when compared with other turfgrass species. This trait should be evaluated during variety development to reduce the risk of failure when new grasses are planted in areas with traffic stress. The objective of this research was to evaluate the wear tolerance of four hybrid bermudagrasses with differing morphological characteristics. Traffic was applied to the hybrid bermudagrass varieties ‘Tifway’, ‘TifSport’, and ‘TifTuf’, as well as an experimental hybrids (04-76) using a traffic simulator for 6 weeks. Leaf morphology (leaf width, length, and angle) and quantitative measure of density and color [normalized difference vegetation index ratio (NDVI), dark green color index (DGCI), and percent green turf color] were characterized before traffic, and then percent green turf color after 6 weeks of traffic was measured to estimate wear tolerance. ‘TifTuf’ hybrid bermudagrass provided the greatest wear tolerance, as well as the narrowest and shortest leaf lengths, greatest NDVI values and percent green color, and lowest DGCI before traffic. Conversely, 04-76 produced the poorest wear tolerance, as well as the widest and longest leaves, lowest NDVI values and percent green color, and highest DGCI values before traffic. Regression analysis determined that DGCI, leaf length, and leaf width were inversely, or negatively, correlated to wear tolerance, whereas percent green turf color before traffic was directly correlated to wear tolerance. For these hybrids, DGCI had the strongest correlation to increased wear tolerance.