STUDIES ON THE DURATION OF Poa pratensis CULTIVAR TESTING

1985 ◽  
Vol 65 (2) ◽  
pp. 351-356 ◽  
Author(s):  
S. H. NELSON
Keyword(s):  
Relative Stability ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Considerable Change ◽  
Early Years ◽  
Growing Seasons ◽  
Changing Trends ◽  
Color Density ◽  
Statistical Separation

Color (C), density (D), and weediness (W) score data of Kentucky bluegrass cultivars were evaluated individually, as well as indices (C + D)/2, (C + D)/2-W, (C + D–W)/2, for Kentucky bluegrass cultivars in their second to seventh growing seasons. Considerable change in ranking occurred in the early years and relative stability was not achieved until the fifth year. Thus, the averaging of changing trends in the early years could be misleading. The use of indices added a degree of uniformity which identified poor and good cultivars, but the statistical separation was not enhanced among the cultivars. The (C + D)/2 index is recommended since weediness seemed to be a function of density and weediness can be controlled. The study identified the need for at least 5 years of testing, particularly on the Canadian prairies.Key words: Kentucky bluegrass, color, density, weediness, indices

scholarly journals Matching Subjective Assessments of Sod Strength to Quantitative Measurements of Peak Shear Force with Predominately Kentucky Bluegrass Sod

HortScience ◽  
2015 ◽  
Vol 50 (8) ◽  
pp. 1248-1251
Author(s):  
Karl Guillard ◽  
Richard J.M. Fitzpatrick ◽  
Holly Burdett
Keyword(s):  
Shear Strength ◽  
Rhode Island ◽  
Shear Force ◽  
Quantitative Methods ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Peak Force ◽  
Growing Seasons ◽  
Quantitative Measurements ◽  
Subjective Assessments

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.

Grazing exclosures reveal divergent patterns of change in bunchgrass grasslands of Western Canada

Botany ◽  
2021 ◽  
Vol 99 (1) ◽  
pp. 9-22
Author(s):  
Gary E. Bradfield ◽  
W.F. Preston Cumming ◽  
Reg F. Newman ◽  
Maja Krzic
Keyword(s):  
Vegetation Change ◽  
Structural Changes ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Growing Seasons ◽  
South Central ◽  
Species Cover ◽  
Rough Fescue ◽  
Dominant Grasses

Thirty-six long-term (14–83 years) cattle grazing exclosures and adjacent grazed pastures spanning a climatic gradient from cooler–wetter to warmer–drier growing seasons in south-central British Columbia were compared for temporal vegetation change. Trajectories of temporal vegetation change from non-metric multidimensional scaling were mostly scattered for the grazed areas, but more directed toward the dominant grasses, primarily rough fescue (Festuca campestris) or Kentucky bluegrass (Poa pratensis), for the exclosures. Plant community differences, detected only after 10 years of grazing exclusion, were primarily due to structural shifts in overall species cover related to growth increases of the dominant grasses inside exclosures. Species richness remained unchanged between the first and last sampling dates in both grazed areas and exclosures, with both treatments showing moderate degrees (15%–30%) of turnover in species composition. Shannon diversity declined in both treatments as a result of the structural changes in species cover. The results highlight the value of repeated monitoring of long-term exclosures for assessment of grassland resiliency to grazing. Further studies of the interaction of grazing and climate are needed for a more complete understanding of the ongoing vegetation change.

Herbicide and Fire Effects on Smooth Brome (Bromus inermis) and Kentucky Bluegrass (Poa pratensis) in Invaded Prairie Remnants

2011 ◽  
Vol 4 (2) ◽  
pp. 189-197 ◽  
Author(s):  
Matt A. Bahm ◽  
Thomas G. Barnes ◽  
Kent C. Jensen
Keyword(s):  
Untreated Control ◽  
Poa Pratensis ◽  
Plant Cover ◽  
Growing Season ◽  
Kentucky Bluegrass ◽  
Perennial Grasses ◽  
Native Plant ◽  
Smooth Brome ◽  
The Third ◽  
Growing Seasons

AbstractSmooth brome and Kentucky bluegrass are introduced cool-season perennial grasses known to invade grasslands throughout North America. During the fall of 2005 and spring of 2006, we implemented a restoration study at six native prairie sites in eastern South Dakota that have been invaded by smooth brome and Kentucky bluegrass. Treatments included five herbicide combinations, a fall prescribed burn, and an untreated control to determine the potential of each for renovation of invaded native grasslands. Herbicide treatments tested were sulfosulfuron, imazapyr, imazapic + sulfosulfuron, and imazapyr + imazapic, and were applied in late September 2005 and mid-May 2006. Untreated control plots averaged 64% (± 3.1) smooth brome cover and 38% (± 5.5) Kentucky bluegrass cover after the third growing season. Smooth brome cover in herbicide treated plots ranged from 6 to 23% and Kentucky bluegrass cover ranged from 15 to 35% after the third growing season. Smooth brome cover was 20% (± 2.9) and Kentucky bluegrass cover was 19% (± 4.0) in burned plots after the third growing season. Spring and fall treatments had similar native plant cover after three growing seasons. Spring and fall application of 0.33 kg ai ha−1 imazapyr and 0.10 kg ai ha−1 imazapic + 0.16 kg ai ha−1 imazapyr had ≤ 10% smooth brome cover and increased native species cover after three growing seasons. Herbicides were effective at reducing cover of smooth brome and Kentucky bluegrass, and can be incorporated with other management strategies to restore prairie remnants.

scholarly journals Turfgrass Seed and Sod Establishment on Soil Amended with Biosolid Compost

2005 ◽  
Vol 15 (3) ◽  
pp. 577-583 ◽  
Author(s):  
Douglas T. Linde ◽  
Lawrence D. Hepner
Keyword(s):  
Soil Amendment ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Ammonium Nitrogen ◽  
Adjacent Area ◽  
Percent Cover ◽  
Color Density ◽  
Biosolid Compost ◽  
The One ◽  
Treatment Application

Using composted biosolid waste as a soil amendment for turfgrass is becoming a common method for disposing of municipal waste. This study was conducted to evaluate turfgrass seed and sod establishment on subsoil amended with various rates of biosolid compost. To a soil that had its A-horizon removed, biosolid compost derived from sewage sludge was incorporated at rates of 0, 132, 270, and 402 yard3/acre. A fifth treatment included a single application of fertilizer at time of sowing. Kentucky bluegrass (Poa pratensis) was seeded immediately after treatment application. The treatments were repeated on an adjacent area using kentucky bluegrass sod. For 1.5 years, turfgrass percent cover, color, density, and weeds were evaluated. Overall, the compost performed well as a soil amendment for turfgrass. A 2- to 3-inch depth of compost appeared to be the best incorporation rate for the soil and compost used in this study. High salinity and excessive ammonium nitrogen (NH4-N) levels in the compost-amended soil at the time of establishment caused a 2- to 3-week delay in seed and sod establishment. After the 2 to 3 weeks, the compost-amended plots outperformed the one-time fertilized plots in turfgrass color and density. Turf managers may want to account for the delay in establishment when incorporating a 60-day-cured compost.

Nitrogen fixation associated with 'Park' Kentucky bluegrass (Poapratensis L.)

1979 ◽  
Vol 25 (10) ◽  
pp. 1197-1200 ◽  
Author(s):  
R. C. Shearman ◽  
W. L. Pedersen ◽  
R. V. Klucas ◽  
E. J. Kinbacher
Keyword(s):  
Nitrogen Fixation ◽  
Acetylene Reduction ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Acetylene Reduction Activity ◽  
Controlled Environment ◽  
Nitrogen Accumulation ◽  
Reduction Activity ◽  
Significant Difference ◽  
Reduction Assay

Associative nitrogen fixation in Kentucky bluegrass (Poa pratensis L.) turfs inoculated with five nitrogen-fixing bacterial isolates was evaluated using the acetylene reduction assay and nitrogen accumulation as indicators of fixation. 'Park' and 'Nugget' Kentucky bluegrass turfs were grown in controlled environment chambers and inoculated with Klebsiella pneumoniae (W-2, W-6, and W-14), Erwinia herbicola (W-8), and Enterobacter cloacae (W-11). 'Park' inoculated with K. pneumoniae (W-6) had significant acetylene reduction activity using undisturbed turfs. Other treatments including turfs treated with heat-killed cells had no significant difference in acetylene reduction. In a second study, 'Park' and 'South Dakota Certified' turfs were grown in a greenhouse and inoculated with K. pneumoniae (W-6) and E. herbicola (W-8). 'Park' inoculated with K. pneumoniae (W-6) had increased acetylene reduction activity rates and also a greater nitrogen accumulation in aerial tissues when compared to controls. Acetylene reduction activity was correlated (r = 0.92) to nitrogen accumulation. Other treatments did not effectively increase acetylene reduction activity or nitrogen accumulation.

Nitrogen fixation (acetylene reduction) by Klebsiella pneumoniae in association with 'Park' Kentucky bluegrass (Poa pratensis L.)

1981 ◽  
Vol 27 (1) ◽  
pp. 52-56 ◽  
Author(s):  
L. V. Wood ◽  
R. V. Klucas ◽  
R. C. Shearman
Keyword(s):  
Nitrogen Fixation ◽  
Klebsiella Pneumoniae ◽  
Ethylene Production ◽  
Acetylene Reduction ◽  
Nitrogenase Activity ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Surface Sterilization ◽  
Reducing Activity ◽  
Acetylene Reducing Activity

Turfs of 'Park' Kentucky bluegrass reestablished in the greenhouse and inoculated with Klebsiella pneumoniae (W6) showed significantly increased nitrogen fixation (acetylene reduction) compared with control turfs. Mean ethylene production rates per pot were 368 nmol h−1 for K. pneumoniae treated turfs, 55 nmol h−1 for heat-killed K. pneumoniae treated turfs, and 44 nmol h−1 for untreated turfs. Calculated lag periods before activity was observed were generally very short (less than 1 h).When 'Park' Kentucky bluegrass was grown from seed on soil-less medium of Turface, a fired aggregate clay, inoculation with K. pneumoniae (W6) resulted in 9 of 11 turfs showing nitrogenase activity (mean ethylene producion rate per pot was 195 nmol h−1). Only 3 of 11 turfs treated with heat-killed K. pneumoniae showed any activity and their mean rate of ethylene production (40 nmol h−1 per pot) was significantly lower than that for turfs treated with K. pneumoniae.Using the 'Park'–Turface soil-less model system it was shown that acetylene reducing activity was (i) root associated, (ii) generally highest at a depth of 1–4 cm below the surface, (iii) enhanced by washing excised roots, and (iv) inhibited by surface sterilization of excised roots. Klebsiella pneumoniae was recovered from Turface and roots showing acetylene reducing activity.

SELECTIVE CONTROL OF ANNUAL BLUEGRASS IN KENTUCKY BLUEGRASS TURF WITH LINURON

1979 ◽  
Vol 59 (2) ◽  
pp. 469-473 ◽  
Author(s):  
R. G. INGRATTA ◽  
G. R. STEPHENSON ◽  
C. M. SWITZER
Keyword(s):  
Temperature Regime ◽  
Poa Pratensis ◽  
Kentucky Bluegrass ◽  
Controlled Environment ◽  
Night Temperature ◽  
Annual Bluegrass ◽  
Selective Control ◽  
Excellent Control

Optimum top growth of annual bluegrass (Pao annua L.) and Kentucky bluegrass (Poa pratensis L.) was obtained at 24/12 °C day/night temperature regime in controlled environment studies. The tolerance of seedling Kentucky bluegrass to linuron [3-(3,4-dichlorophenyl)-1)methylurea] appeared to be greatest at this temperature regime when photoperiods were 16 h in length. A granular formulation of linuron gave excellent control of annual bluegrass in Kentucky bluegrass turf at 6.7 kg/ha when applied postemergence. At this rate, all culitivars of Kentucky bluegrass tested, with the exception of Fylking, were tolerant to linuron as a granular formulation. After application of linuron at 3.4–6.7 kg/ha, phytotoxic residues remained in the soil at sufficient levels to injure seedling Kentucky bluegrass for up to 3 mo.

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