Poa Pratensis Research Articles

Nemli-Mezotermal İklim Kuşağında Yer Alan Hasanlar Köyü Mera Islahı Çalışmalarının Etkinliğinin Belirlenmesi

The aim of this study is to determine the current status of the rangeland, whose vegetation was completely renewed in 2013, as of 2021. During the 7-8 years after the rehabilitation study, the proportions of the species in the vegetation changed significantly, although there was no significant change in the soil cover value of the plants. Soil coverage rate of pasture vegetation is 98.20%; the ratios of decreaser, increaser and invasive species are 13.14%, 5.39% and 81.77%, respectively. It has been determined that the stubble height remaining after grazing in the pasture is less than 50% of the average vegetation height, all accessible parts of the pasture are grazed, the reproductive plant parts of the decreasing and increasing plant species are very few, and they can develop under the protection of thorny plants that animals cannot reach. It has been also determined that all herbaceous plants except thorny plants are grazing at varying rates in the pasture. According to all these data, it was concluded that the pasture was intensively grazed. Perennial grass (Lolium perenne) with the highest rate and the most common decreaser in vegetation with a frequency of 3.97% and a frequency of 80%, while the invasive species is a wild blackberry (Rubus sp.) with a rate of 46.54% and a frequency of 90%. According to their rate and distribution in vegetation, forage plant species that can be preferred in all kinds of seeding operations in pastures in this and similar ecologies; Lolium perenne, Dactylis glomerata, Poa pratensis, Lotus corniculatus, Trifolium fragiferum and Trifolium repens, the most important shrub species to be controlled is wild blackberry. The employment of goats, which preferably graze blackberries and other shrubs and even other herbaceous plants that cattle do not prefer, can be recommended as the most economical and environmentally friendly weed control method. Otherwise, vegetation should be renewed at regular intervals to protect the pasture from invasive species.

First Report of Powdery Mildew Caused by Blumeria graminis on Poapratensis var. anceps 'Qinghai' in China.

Poa pratensis, an important cool-season perennial grass, is widely cultivated for construction of grasslands and ecological management of Qinghai-Tibet Plateau (Dong et al. 2020). Poa pratensis var. anceps Gaud cv. Qinghai (PPAQ) is a variant of P. pratensis (Liu et al. 2009). In June 2016, powdery mildew was observed on PPAQ in an artificial field of PPAQ in Haiyan county of Haibei Tibetan Autonomous Prefecture, Qinghai province, China (36°59'17.76″N, 100°52'54.01″E). Approximately 30 to 50% of leaves (approximate 10 ha) were affected. Initially, irregular white mycelial colonies were observed on the adaxial surface of affected leaves. The colonies increased in number and size, and later covered a large area of leaves and stems. In advanced stages of disease, the colonies covered the whole adaxial surface and white patches appeared on the abaxial surface of affected leaves, and eventually caused leaf death. Conidiophores were unbranched, measuring 160 to 235 × 4 to 13 μm, and borne vertically on hyphae. Each conidiophore produced 4 to 11 conidia in a chain. The conidia were oval, one-celled, and hyaline, measuring 22 to 40 ×10 to 21 μm (n = 50). Chasmothecia were yellow, spherical, and 172 to 240 μm in diameter (n = 20), each of which contained 8 to 17 asci. The appendages were few, and hyphoid. Asci were oblong or ovate, measuring 79 to 115 × 31 to 45 μm (n = 20). Asci were petiolate, containing eight ascospores. Ascospores were round to oval, colorless, one-celled, measuring 17 to 33 × 8 to 14 μm (n = 50). Based on morphological characteristics, the fungal organism was identified as Blumeria graminis (DC.) Speer. To confirm the identification, the internal transcribed spacer (ITS) of 612 bp was amplified from DNA of conidia using ITS5 and P3 primers (Takamatsu et al. 2009). The ITS sequence was deposited in GenBank database (Accession No. MF429949). The ITS showed 95% sequence similarity with those of B. graminis on Poa nemoralis in USA (Accession No. AB273560) and on P. bullbosa in Iran (Accession No. AB273551) (Inuma et al. 2007). Five two-month-old healthy plants were inoculated by spraying a spore suspension (1× 105 conidia ml-1) prepared from conidia brushed from infected plants; five plants sprayed with sterile distilled water served as controls. All the plants were maintained in a growth chamber with a constant temperature of 20°C, a 12 h/12 h light/dark diurnal cycle, and 70% humidity. Two weeks after inoculation, symptoms of powdery mildew were observed on all inoculated plants, whereas the control plants remained symptomless. The same fungus was confirmed by morphological characterization and molecular assays as described above. B. graminis has been reported on P. pratensis in USA (Dugan and Newcombe 2007), Israel (Voytyuk et al. 2009), and China (Zhang et al. 2014), but has not previously been reported on PPAQ. As far as we know, this is the first report of powdery mildew caused by B. graminis on PPAQ in China. These findings indicated that the health of PPAQ was substantially threaten when infected by powdery mildew, therefore, our results also contributed some valuable information how to diagnose this disease on PPAQ in China.

Variation of microsporogenesis in sexual, apomictic and recombinant plants of Poa pratensis L.

Apomixis is a rather widespread phenomenon in plants. It is defined as the asexual formation of a seed from the maternal tissues of the ovule, avoiding the processes of meiosis and fertilization. Some species are facultative apomicts and form seeds by means of sexual and apomictic pathways to different extents. This is the case of Poa pratensis, the Kentucky bluegrass, which reproduces by aposporous pseudogamous facultative apomixis. This grass is one of the most studied apomictic systems, however some aspects, such as the male meiotic behavior, have not been so far investigated. In this study the process of microsporogenesis in genotypes of P. pratensis with a different mode of reproduction was investigated. The analysis revealed an almost regular meiosis in the sexual plants whereas apomictic genotypes exhibited different levels of meiotic irregularities, mainly due to cell fusion and irregular segregation in I and II division. Our data did not reveal evident connections between the extent and types of abnormalities and the components of apomixis, apomeiosis and parthenogenesis. The meiotic behavior of the examined plants was discussed in the light of their origin.

Single-Plant Grain Yield in Corn (Zea mays L.) Based on Emergence Date, Seed Size, Sowing Depth, and Plant to Plant Distance

The lack of seedling emergence uniformity in corn (Zea mays L.) is concerning for producers in the Midwestern U.S. These producers believe that just a few hours delay in emergence can increase interplant competition and decrease single-plant yield, thus reducing overall crop yield. It is speculated that lack of uniformity in seedling emergence occurs due to a variation in seed size within a commercial bag of seed, and variation in seed depth placement at sowing throughout the field. Due to these concerns, producers evaluate size seed variation within the bag before sowing. To date, research has investigated sowing dates, growing degree days, or varying sowing depths to simulate a delay in seedling emergence. These studies are important for understanding the effects of delayed emergence on overall yield, but they fail to examine the effect of inter-plant competition on single-plant yield. The objective of this study was to understand the effect of seed size and sowing depth on emergence and subsequent single-plant yield in a bare soil and a perennial groundcover (PGC) cropping system. Commercially sized seed and seed sized further in the laboratory to obtain a narrower seed size distribution were sown in Kentucky bluegrass and bare soil systems and at two sowing depths of 3.18 and 6.35 cm. The two-year experiment was planted in a split-plot design with four replications. Individual plants were flagged at emergence, and harvested individually. Seed placement was crucial to uniform emergence in both cropping systems, while seed size did not affect emergence in either system. The PGC cropping system delayed seed corn emergence and reduced grain yield as much as 50%. Single-plant yield decreased with delayed corn emergence in both cropping systems. Yield decrease as a function of emergence date followed either a quadratic or linear trend in each growing season, likely related to post emergence environmental factors. This information is important for producers and seed companies to understand the effect of seed size and sowing depth on yield and emergence. This study demonstrates that uniform sowing depth is more important than seed size distribution.

Temporal Recovery of Polymer-Coated Urea-N by Kentucky Bluegrass in the Field

Relative to soluble N sources, controlled release fertilizer (CRF) fosters consistent turfgrass growth response and improved canopy quality while reducing N loss as nitrate, ammonia, and/or N2O from target systems. Commercial CRFs afford turfgrass managers greater operational efficiency and flexibility in nutrient management planning and compel the investigation of application rate thresholds to guide regional agencies tasked with their regulation. The experimental objective was to systematically evaluate, under an array of field conditions, Kentucky bluegrass (Poa pratensis L.) vigor/yield, fertilizer N offtake, canopy density, and canopy color temporal response to a single application of granular N fertilizer made at practical rates. In May of 2014 and 2015, plots within a mature Kentucky bluegrass system were fertilized by conventional urea or Duration 45 polymer coated urea (PCU) at a N rate of 43.9 kg·ha−1 (0.9 lbs N·1000 ft−2); or PCU (Duration 90, Duration 120, or 43% N Polyon) at a N rate of 87.8 kg·ha−1 (1.8 lbs N·1000 ft−2). Resulting measures of the described dependent variables proved similar over both growing seasons and were highly dependent on the N rate and PCU attribute. Following 18-week evaluations, the average total percent fertilizer N recoveries from conventional urea, Duration 45, Duration 90, Duration 120, and Polyon (43% N) were 63%, 87%, 82%, 78%, and 77%, respectively. Temporal release among commercial PCU fertilizers indicates varying suitability by commodity and seasonal nutrient requirements. Hypothesis tests on experiment-end unaccounted fertilizer N totals show one 87.8 kg N·ha−1 application of the described 100% PCU fertilizer treatments poses no greater environmental risk than a 43.9 kg N·ha−1 application of conventional urea fertilizer.

Carbon loss in tile drainage and surface runoff from a clay loam soil after a half century of continuous and rotational cropping

Tile drainage and surface runoff are major pathways for pollution of water resources by agricultural nutrients and chemicals. Little is known, however, of the pathways and amounts of carbon entry into water resources from agricultural land. This paper evaluates dissolved organic carbon (DOC) and dissolved inorganic carbon (DIC) losses in tile drainage and surface runoff from a Brookston clay loam after more than a half century of monoculture maize ( Zea mays L.), continuous bluegrass sod ( Poa Pratensis L.), and maize-oat ( Avena sativa L.)–alfalfa ( Medicago sativa L.)–alfalfa rotation. Water loss in tile drainage and surface runoff accounted for 27%, 32%, and 18% of annual precipitation (876 mm) for rotation, monoculture maize, and continuous sod, respectively. Tile drainage comprised 66%–89% of water loss from rotation and continuous sod, but only 15% from monoculture maize, with the remaining 85% of water loss from monoculture maize due to surface runoff. On an annualized basis, the measured dissolved C loss was 79 and 83 kg C ha–1 yr–1) from rotation and continuous sod, respectively, while 49 kg C ha–1 yr–1 was lost from monoculture maize. As up to 9% off-gassing loss of CO2 from water samples was measured, total dissolved carbon losses in tile drainage and runoff water were likely greater. For Brookston clay loam soil, leaching into tile drains was the dominant mechanism for dissolved carbon loss from long-term continuous sod and crop rotation, while surface runoff was the dominant mechanism for dissolved carbon loss from long-term monoculture maize.

Vascular occlusion associated with abiotic stress is a causal agent of silvertop in perennial grasses

Silvertop (sterile heads) of perennial cool-season grasses is common in aging stands grown for seed production. It is associated with yield reduction, but the causal agent(s) has not been determined. A study was conducted to examine the cytology of grass tillers with and without silvertop. A series of cross sections of stems from field samples of Kentucky bluegrass and meadow bromegrass (where signs of insect injury or fungal infection were absent) revealed abnormalities in the tissues above the last node in tillers exhibiting silvertop, while cells in the stems of healthy tillers appeared normal. Most cells from stems exhibiting silvertop became irregular and distorted, and eventually lost their integrity and shape altogether. At the terminal nodes of these stems, the sieve plates of xylem vessels were occluded with unidentified material, preventing the passage of water to the seed head. The xylem and phloem cells in the leaf sheath and blade surrounding the silvertop stems appeared normal. Spherical bodies in x-section, believed to be fungal mycelium and spores, were occasionally found above the point of tissue necrosis above the last node. Very few spherical bodies were observed below the symptomatic tissue, and none were found in the terminal node. The blockages observed in the water-conducting vessels to the seed head appear to have been induced by the plant as a response to abiotic stress, rather than by external biotic factors such as insects or pathogens.

Seed Size, Planting Depth, and a Perennial Groundcover System Effect on Corn Emergence and Grain Yield

The intensive corn (Zea mays L.) and soybean (Glycine max (L.) Merr.) production practices currently used in the Midwestern U.S. concern producers and stakeholders. The negative impact of these two-crop rotations on the environment affects water quality and soil erosion and increases flooding risks. Due to these concerns, cover crops and, specifically, perennial groundcover (PGC) cropping systems have gained greater interest. These perennial species have growing patterns compatible with corn and soybean, and can help rebuild the ecosystem while maintaining good cash crop yields. In addition, producers also are interested in the possible effect of seed size and planting depth on uneven emergence in corn. The successful adoption of PGC systems ultimately depends on the successful corn seedling emergence and consistent yield. The objective of the study was to understand the effects of seed characteristics and placement on emergence, grain yield, and grain quality in corn planted using a Kentucky bluegrass (Poa pratensis L.) (KBG)-PGC and a bare-soil cropping system and to determine grain quality attributes and grain moisture dry-down in a PGC field when compared to a conventional cropping system. Commercially-sized seed and seed sized in the laboratory to represent a narrower seed size distribution were planted in KBG-PGC and bare soil systems at two planting depths (3.18 and 6.35 cm). The two-year experiments were planted in a split-plot RCB design with four replications. Individual plants were flagged at emergence, and ears from each plant were harvested individually. Separating the seed lot into different size distributions did not affect seed germination under ideal (standard germination and speed of germination tests) or stressful (cold test) conditions. Seed size distribution also did not influence emergence rate and yield in a conventional tillage (bare soils) or KBG-PGC system. These results indicate that seed sizing specifications and seed size cutoffs currently used by seed companies are suitable for uniform emergence and maximum grain yield in both cropping systems. Seed placement was crucial to uniform emergence in both cropping systems, while seed size distribution did not play a role in emergence for either system. The PGC cropping system delayed seed corn emergence and reduced grain yields as much as 50%. This information is important for those producers considering adopting a PGC system because it demonstrates that uniform planting depth is more important than seed size distribution.

Community associations and ecological drivers of understory vegetation across temperate forests of Kashmir Himalayas, India

We assessed the understory vegetation types in temperate Kashmir Himalayan coniferous forests, their species composition and what function ecological drivers execute in shaping compositional trends using a multivariate statistical approach. The agglomerative clustering analysis depicted eight discrete plant associations in terms of herb species composition with simple underlying indicator species and ecological drivers. At one extreme, we found alpine and subalpine areas (Tanacetum multicaule Sch.Bip. – Aconitum heterophyllum Wall. ex Royle – Lomatogonium caeruleum (Royle) Harry Sm. ex B.L. Burtt community (TAL)) occupying high elevations (2961.88±205.56 m) with notable species richness (6.04), while lower (2459.36±94.07 m) areas are inhabited by Thalictrum minus L. – Galium aparine L. – Achillea millefolium L. (TGA) community. The Poa pratensis L.– Senecio chrysanthemoides DC. – Clinopodium umbrosum (M.Bieb.) Kuntze (PSC) community was most diverse, supported higher species diversity (Shannon=2.22±0.07; Simpson=0.84±0.01; Fisher's α=4.51±0.30) and also exhibited a maximum number of trails crossing the plot. Canonical Correspondence analysis (CCA) examined the species-ecological interactions and displayed a significant role of most studied environmental variables in the species distribution patterns. The latter in the decreasing significance order comprised precipitation (F = 2.3; p = 0.001), latitude (F = 2.15; p = 0.001), grazing (F = 1.56; p = 0.01), longitude (F = 1.63; p = 0.013), slope (F = 1.33; p = 0.07), elevation (F = 1.32; p = 0.07), aspect (F = 0.1; p = 0.47), trails (F = 0.78; p = 0.85) and mean monthly minimum temperature (F = 1.23; p = 0.172). The variance partitioning used to evaluate the comparative significance of topographic, climatic and disturbance factors on understory vegetation composition depicted that topography (14.26%) strongly partitioned the vegetation distribution subsequently followed by climatic (11.52%) and disturbance (4.49%) factors.

Differential Metabolomic Responses of Kentucky Bluegrass Cultivars to Low Nitrogen Stress.

Kentucky bluegrass (Poa pratensis L.) is a cool-season turfgrass species that responds strongly to nitrogen (N), but the metabolomic responses of this grass species to N supply is unknown. The N-tolerant cultivar Bluemoon and N-sensitive cultivar Balin were exposed to normal N (15 mM) and low N (0.5 mM) for 21 days for identification of differentially expressed metabolites (DEMs) between normal N and low N treatments. Balin had more reductions of chlorophyll and total soluble protein concentrations and a higher accumulation of superoxide radicals under low N stress. A total of 99 known DEMs were identified in either cultivar or both including 22 amino acids and derivatives, 16 carbohydrates, 29 organic acids, and 32 other metabolites. In Bluemoon, β-alanine metabolism was most enriched, followed by alanine, aspartate, and glutamate metabolism, biosynthesis of valine, leucine, and isoleucine biosynthesis, and glycine, serine, and threonine metabolism. In Balin, alanine, aspartate, and glutamate metabolism were most enriched, followed by the tricarboxylic acid (TCA), glyoxylate and decarbohydrate metabolism, and carbon fixation. Bluemoon generally maintained higher TCA cycle capacity and had more downregulated amino acids, while changes in more organic acids occurred in Balin under low N stress. Some metabolite changes by low-N stress were cultivar-specific. The results suggested that regulation of metabolites related to energy production or energy saving could contribute to low N tolerance in Kentucky bluegrass.

Effect of topdressing of compost, compost tea, and various fertilizers on soil and lawn characteristics

AbstractMany cities in the United States collect and compost yard waste but need more effective and efficient ways to utilize the finished product. Home lawns represent a sizeable area that could benefit from land application of yard waste compost, but little research has been conducted regarding topdressing lawns with compost. The objectives of this study were to compare the impact of topdressing yard waste compost relative to organic and inorganic fertilizers in a mature, predominantly Kentucky bluegrass (Poa pratensis L.) lawn in Wisconsin. Three different composts (two from yard waste and one from food waste), two organic fertilizers, and a compost–compost tea combination were compared against a traditional synthetic fertilization program and a nontreated control. Treatments receiving compost (1.3 cm depth per year, in two equally sized applications) maintained acceptable turf quality over the 3.5‐yr study period and resulted in significant improvements in several important physical properties of the soil. Fertilizers were also able to maintain acceptable turfgrass quality but had no impact on the physical properties of soil over the study period relative to the control. Organic and synthetic fertilizers reduced weed populations compared with the control, though the compost treatments did not. Compost and one of the organic fertilizers significantly increased the levels of soil test P but did not reach levels of environmental concern.

Assessing the potential of native ecotypes of Poa pratensis L. for forage yield and phytochemical compositions under water deficit conditions

Evaluation of forage yield and antioxidant activity in Poa pratensis with high quality and good spring green-up forage might help variety improvement for use under water deficit condition. Germplasm and phenotypic diversity evaluations lay a foundation for genotype selection and improvement of varieties for drought tolerance in P. pratensis. The present study was conducted to assess the genetic potential of a collection of P. pratensis accessions for drought stress and to identify the association between polyphenol compounds and forage yield traits. Vegetative clone samples of 100 accessions collected from a diverse geographical area of Iran were clonally propagated in a greenhouse and evaluated in the field under two moisture regimes (non-stress and drought stress) in 2018 and 2019. Drought stress had negative effects on fresh and dry forage yields and reduced phenotypic variances. On average, drought stress reduced fresh and dry forage yields by 45% and 28%, respectively. The results of Mantel test showed no significant correlation between forage yield traits and geographical distances. Genetic coefficients of variation for forage yield and most of the phytochemicals were lower under drought stress, suggesting that deficit irrigation may reduce genetic variation for the tested traits. The estimates of heritability were higher under non-stress conditions than under drought stress treatment for forage yield traits and few polyphenols. However, the majority of polyphenol compounds had higher heritability than forage yield traits under drought stress, which suggests the potential for indirect selection. The ‘Ciakhor’, ‘Damavand’, ‘Karvandan’, ‘Abrumand’, and ‘Abr2’ accessions had high quantities for polyphenols and yield traits under both moisture regimes. These accessions are promising candidates for use in variety crossing programs and for developing high-yielding varieties under water-deficit conditions.

The Influence of Zn and Cd Accumulation on the Growth and Development of Medicinal Plants in the Impact Zone of the Novocherkassk Power Station

Over the pastdecade, particular attention has been paid to studies of the chemical composition of medical plants to identify the possible negative consequences of using raw plant material polluted with heavy metals for the production of medical drugs. In our study, we analyzed the chemical composition of the medical plants growing in the impact area of the Novocherkassk power station. Specifically, the plants Artemisia austriaca, Poa pratensis and Elytrigia repenswere examined for the analysis.The content and distribution of Zn and Cd, which are most distributed in industrial emissions and belong to the first class of hazardous elements, were measured. The maximum permissible content (MPC) of Zn in the raw material of Artemisia austriaca and Elytrigia repens was found, as was the maximum content of Cd in all analyzed plants growing in the 5km area around thepower station. The plant Artemisia austriacawasfound to have Zn and Cd accumulation in itsabovegroundcomponents, while in Poa pratensis and Elytrigia repens, accumulation was in the roots. The morphobiometric parameters of the plants were mostly dependent on the soil properties, followed by the degree of technogenic load. The content of Zn and Cd in the medical drugs was higher than the MPC without visible features of heavy metal pollution and so these plants weredangerous for human health.
 Keywords: heavy metals, technogenic load, phytoreagents, morphometric parameters

Poa pratensis (smooth meadow-grass)

Poa pratensis (smooth meadow-grass)

Glutamine synthetase gene PpGS1.1 negatively regulates the powdery mildew resistance in Kentucky bluegrass.

Excessive nitrogen (N) application may induce powdery mildew (PM) in perennial grasses, but the resistance mechanisms to PM remain unclear. This study evaluated the physiological and molecular mechanisms of PM resistance affected by N supplies in Kentucky bluegrass (Poa pratensis L.). Cultivar 'Bluemoon' (N tolerant) and 'Balin' (N sensitive) were treated with low N (0.5mM), normal N (15mM), and high N (30mM) for 21d in a greenhouse. With increasing N levels, the disease growth was more severe in 'Balin' than in 'Bluemoon'. RNA-seq and weighted gene coexpression network analysis revealed that the PpGS1.1 gene encoding glutamine synthetase was a potential hub gene for PM resistance after comparisons across cultivars and N treatments. The N metabolism pathway was connected with the plant-pathogen interaction pathway via PpGS1.1. The expression of PpGS1.1 in rice protoplasts indicated that the protein was located in the nucleus and cytoplasm. Overexpression of PpGS1.1 in wild-type Kentucky bluegrass increased carbon and N contents, and the transgenic plants became more susceptible to PM with a lower wax density. The most differentially expressed genes (DEGs) for N metabolism were upregulated and DEGs for fatty acid metabolism pathway were downregulated in the overexpression lines. The results elucidated mechanisms of PM resistance in relation to N metabolism in Kentucky bluegrass.

Новые ассоциации и высшие синтаксоны ивняков в восточноевропейском секторе Арктики

Новые ассоциации и высшие синтаксоны ивняков в восточноевропейском секторе Арктики

АССОРТИМЕНТ ГАЗОННЫХ ТРАВ И СОСТОЯНИЕ ГАЗОНОВ В ОБЪЕКТАХ ОЗЕЛЕНЕНИЯ Г. СТАВРОПОЛЯ

In 2019–2021, a study of the species composition and current state of ornamental lawns in two parks, a boulevard and ten public gardens in Stavropol was conducted to evaluate the range of lawns used, their current state and to determine the effectiveness of the management measures taken to improve the quality of lawn coverings. The collected database can be used to make effective economic decisions to optimize the range and increase the ecological and aesthetic value of landscaping objects. The longevity of a lawn depends on the selection of lawn formers adapted to the given soil and climate conditions, capable of producing a high-quality lawn for many years and on proper care. The survey found that lawn grasses of the first and second quality groups were mainly used to create lawn coverings – Poa pratensis L., Festuca rubra L., Lolium perenne L., with Trifolium repens L. subseeds. In most cases, grass mixtures were used to create lawns. Recently, a more drought-resistant species, Festuca arundinacea Schreb, has been used more often as a lawn-forming agent. Most of the surveyed grass stands were rated “satisfactory” and “good” lawn. Stationary irrigation systems have been installed in a number of new landscaping facilities; rolled lawns have been used more often. Among the factors of negative impact on non-irrigated lawns are long dry periods, which led to the burning of lawn grass up to II–IV points, in 2018 – more than 50 days, in 2019 – more than 40 days, in 2020 – more than 60 days. At the same time, they lost their decorative, environmental and sanitary functions. Another negative environmental factor was the shading of lawns by tree crowns, which leads to thinning of the herbage, loss of decorative effect and the formation of dead covers. Additional shading of the lawn grasses was provided by leaf litter which was not removed in time. Almost all lawns had weed species that increased in number with age (clogging 1–3 points, abundance r-3). As a rule, mowing lawns did not destroy perennial weeds, the renewal zones of which were below the cut-off level of the lawn mower. No insect and disease damage to plants was detected. Negative anthropogenic disturbances on the surveyed landscaping objects are trampling, laying trails, dog walking. Lawns are regularly seeded and repaired.

Required mowing events of transgenic Kentucky bluegrass cultivars compared with conventional turfgrass cultivar blends and species mixtures

AbstractMowing is a labor‐intensive yet important cultural practice to maximize turfgrass health and performance. Selecting cultivars with a slower vertical growth habit can help reduce mowing frequency and improve turfgrass quality (TQ). New transgenic Kentucky bluegrass (Poa pratensis L.) (KBG) cultivars with a dwarf growth habit have been developed by overexpressing the gibberellin 2‐oxidase pathway. However, the impact of this overexpression on the number of required mowing events and mowing frequency in the field is unknown. Therefore, the primary objective of this research was to quantify the required number of mowing events based on the one‐third rule of four transgenic cultivars (‘ProVista’) (PV) and 16 conventional turfgrass cultivars, blends, and mixtures. Over the 2‐yr research period, four PV cultivars in the top statistical group averaged ≤21 mowing events, whereas all other turfgrasses averaged ≥41 mowing events. For mowing frequency, all PV cultivars required an average mowing frequency of ≥20 d, whereas all other turfgrasses required an average mowing frequency of ≤10 d. Although the PV cultivars required half as many mowing events, two of the PV cultivars were consistently in the top statistical group for TQ. The PV KBG cultivars represent new technology for turfgrass genetics with the novel trait of reduced mowing that can benefit the industry by reducing mower emissions, noise, and use, as well as increased TQ and flexibility for turfgrass practitioners, since mowing frequency can be extended.

Establishment of Kentucky bluegrass and tall fescue seeded after herbicide application

AbstractWeed control before seeding is often required for successful turfgrass establishment, since weed interference prior to turfgrass tillering causes a reduction of cover and density. However, herbicides differ widely in the delay required after herbicide application before seeding can occur without injury to seedlings. The objective of this research was to determine the influence of three selective postemergence grass, broadleaf, and sedge herbicides on the cover and density of Kentucky bluegrass (Poa pratensis L.) and tall fescue (Schedonorus arundinaceus Schreb.) seeded 0, 3, 7 or 14 d after herbicide application. Herbicide treatments included: an untreated control, 2,4‐D + 2‐(2‐methyl‐4‐chlorophenoxy)propionic acid (MCPP) + dicamba (1.64 lb acid equivalent acre–1), quinclorac (0.75 lb a.i. acre–1), halosulfuron‐methyl (0.06 lb a.i. acre–1), and dithiopyr (0.50 lb a.i. acre–1), which was included for comparison. Seeding between 0 to 14 d after an application of 2,4‐D + MCPP + dicamba or quinclorac had little or no effect on Kentucky bluegrass or tall fescue cover in Manhattan, KS, and Wooster, OH. Halosulfuron‐methyl reduced the cover of both turfgrass species when seeded 0 or 7 d after application. This research demonstrates that turfgrass managers who unknowingly seed into areas treated with 2,4‐D + MCPP + dicamba or quinclorac within 0 to 14 d after treatment are likely to observe successful establishment of Kentucky bluegrass or tall fescue under the conditions evaluated in these experiments.

Burn and mechanical residue removal methods on production‐life of Kentucky bluegrass

AbstractGiven the importance of Kentucky bluegrass (Poa pratensis L.) seed production in the inland Pacific Northwest, USA, and the difficulty to predict and maintain seed yields as production fields age, greater knowledge of the impact of reduced or nonthermal practices on seed yield and stand longevity is necessary. Longer‐term studies (>3 yr) are needed to maintain high bluegrass seed yields, reduce soil erosion, and amortize the expense of stand establishment. The purpose of this study was to measure the impact of residue management practice on seed production throughout the expected 7‐yr life of a bluegrass field. Four residue management treatments—full load burn (FLB), bale then burn (BB), bale then mow then harrow (MEC), and rotation system (SYS) (MEC in Year 1, BB in Year 2, and FLB in Year 3)—were evaluated from 2002–2007. Average seed yields over the entire study period were 774 kg ha–1 in FLB, 742 kg ha–1 in BB, 525 kg ha–1 in MEC, and 600 kg ha–1 in SYS. Nonstanding residue removal was difficult to accomplish using MEC compared with FLB. Reduced‐burn methods (BB and SYS), however, were able to keep this residue level lower than MEC, and therefore yielded more than MEC. Across‐treatment regression suggest that seed yield was negatively influenced by the amount of nonstanding residue in the previous fall (r2 = .64), yet positively influenced by the nitrogen content of standing biomass in the previous fall (r2 = .78). Profitability was highest in BB and FLB. Overall, understanding the factors that relate to stand decline may help growers prolong stand life and increase profitability, while mitigating air quality issues.