THE BIOLOGY OF CANADIAN WEEDS.: 92. Danthonia spicata (L.) BEAUV. IN ROEM. & SCHULT.

1989 ◽  
Vol 69 (4) ◽  
pp. 1217-1233 ◽  
Author(s):  
S. J. DARBYSHIRE ◽  
J. CAYOUETTE
Keyword(s):  
Perennial Grass ◽  
Low Fertility ◽  
Eastern Canada ◽  
Weed Biology ◽  
Competitive Fitness ◽  
Native North American ◽  
Dispersal Unit ◽  
Dry Soil ◽  
Grass Weed ◽  
Danthonia Spicata

Danthonia spicata, poverty-oat grass, is a native North American perennial grass of pioneer habitats. It invades agricultural lands in eastern Canada with dry soil and low fertility. Unpalatable to livestock, it is an increaser species in heavily grazed or nutrient depleted pasture. A polymorphic reproductive system incorporates chasmogamy, cleistogamy and heteromorphic diaspores (dispersal unit). Clavicipitaceous fungal parasites are often present and affect productivity, reproduction, competitive fitness and possibly predation of their hosts.Key words: Danthonia spicata, Poverty oat grass, weed biology

scholarly journals THE BIOLOGY OF CANADIAN WEEDS.: 77.Veratrum viride Ait.

1987 ◽  
Vol 67 (3) ◽  
pp. 777-786 ◽  
Author(s):  
GERALD A. MULLIGAN ◽  
DEREK B. MUNRO
Keyword(s):  
North America ◽  
Chromosome Number ◽  
Biological Data ◽  
Eastern Canada ◽  
The West ◽  
Weed Biology ◽  
Herbaceous Perennial

This paper provides a summary of biological data on Veratrum viride Ait., false hellebore. It is a herbaceous perennial, native to wet habitats in North America. Subspecies viride occurs primarily in eastern Canada and subspecies eschscholtzii (A. Gray) Löve and Löve in the west. Both subspecies have the chromosome number of n = 16, 2n = 32. Ingested material of false hellebore is poisonous to humans and livestock.Key words: False hellebore, Veratrum viride Ait., weed biology

Relationships between soil, forage, and grazing parameter effects on weed incidence in Missouri pastures

2019 ◽  
Vol 34 (3) ◽  
pp. 408-415
Author(s):  
Gatlin Bunton ◽  
Zachary Trower ◽  
Kevin W. Bradley
Keyword(s):  
Soil Ph ◽  
Tall Fescue ◽  
Perennial Grass ◽  
Weed Species ◽  
Perennial Weed ◽  
Soil P ◽  
Weed Density ◽  
Growing Seasons ◽  
Unit Increase ◽  
Grass Weed

AbstractDuring the 2015, 2016, and 2017 growing seasons, a survey of 63 pastures in Missouri was conducted to determine the effects of selected soil and forage parameters on the density of common annual, biennial, and perennial weed species. Permanent sampling areas were established in each pasture at a frequency of one representative 20-m2 area per 4 ha of pasture, and weed species and density in each area were determined at 14-d intervals for a period from mid-April until late September. The parameters evaluated included soil pH, phosphorus (P), potassium (K), magnesium (Mg), calcium (Ca), sulfur (S), zinc (Zn), manganese (Mn), and copper (Cu) concentrations, as well as tall fescue density, forage groundcover density, and stocking rate. An increase of 1 unit in soil pH was associated with 146 fewer weeds per hectare, the largest reduction in weed density in response to any soil parameter. Increased soil pH was associated with the greatest reduction in perennial grass weed density, along with an average reduction of 1,410 brush weeds per hectare for each 1-unit increase in soil pH. Common ragweed, a widespread weed of pastures, could be reduced by 3,056 weeds ha−1 when soil pH was 1 unit greater. A 1-ppm increase in soil P was correlated with a decrease of 206 biennial broadleaf weeds per hectare. Perennial broadleaf weed density was reduced in soils with greater concentrations of P, K, and Ca. Additionally, for every 1% increase of tall fescue and forage groundcover, there was a decrease of 18 and 38 perennial broadleaf weeds per hectare. The results from this research indicate that the density of many common weed species can be reduced with higher soil pH and adjustments to soil macro- and micronutrient concentrations, especially P.

scholarly journals Suppression of annual grass weeds by AR542 endophyte infection in dryland tall fescue pastures

2007 ◽  
Vol 60 ◽  
pp. 164-167 ◽  
Author(s):  
K.N. Tozer ◽  
R.J. Lucas ◽  
G.R. Edwards
Keyword(s):  
Tall Fescue ◽  
Plant Competition ◽  
Perennial Grass ◽  
Subterranean Clover ◽  
Management Tool ◽  
Stocking Rate ◽  
Annual Grass ◽  
Endophyte Infection ◽  
Weed Cover ◽  
Grass Weed

The effect of endophyte infection of tall fescue (with and without AR542 endophyte Neotyphodium coenophialum) plant competition (white versus Caucasian clover with and without subterranean clover overdrilled) and spring stocking rate (10 versus 20 ewes/ha) on the population size of annual grass weeds was monitored in a pasture on dry stony soils in Canterbury Barley grass (Critesion murinum) cover and seedhead production were lower in AR542 than endophyte free pastures and where subterranean clover was overdrilled than where it was not Vulpia hair grass (Vulpia spp) seedhead production and cover were lower where subterranean clover was overdrilled and where Caucasian rather than white clover was sown Ewe stocking rate did not affect annual grass weed cover or seedhead density The results indicate that sowing tall fescue with AR542 endophyte may be a useful management tool to enhance growth of the perennial grass and reduce invasion of barley grass into dryland pastures

Effect of three nitrogen fertilizer sources on denitrification rate under irrigated potato production on sandy soils

2019 ◽  
Vol 99 (2) ◽  
pp. 117-125 ◽  
Author(s):  
Isabelle Perron ◽  
Athyna N. Cambouris ◽  
Bernie J. Zebarth ◽  
Philippe Rochette ◽  
Noura Ziadi
Keyword(s):  
Solanum Tuberosum L ◽  
Sandy Soils ◽  
Potato Production ◽  
N Fertilizer ◽  
Denitrification Rate ◽  
Eastern Canada ◽  
N Losses ◽  
Dry Soil ◽  
Polymer Coated Urea ◽  
Acetylene Blockage

Large inputs of nitrogen (N) are required to optimize yield and quality of potato (Solanum tuberosum L.), and it may result in a high potential for N losses including denitrification. This 5 yr study compared the effect of three N fertilizer sources [ammonium nitrate (AN), ammonium sulfate (AS), and polymer-coated urea (PCU)] at 200 kg N ha−1 (N200) and an unfertilized control (N0) on denitrification rate (DR) from irrigated potato production on a coarse-textured soil in eastern Canada. Fertilizer was banded all at-planting (PCU) or split 40% at-planting and 60% at-hilling (AN and AS). The DR was measured biweekly from planting to harvest at two locations (ridge and furrow) using the acetylene blockage technique. The mean annual DR, averaged across N treatments, ranged from 0.8 to 8.0 μg N2O-N kg dry soil−1 d−1, and it was most closely related to the water inputs in the 72 h before DR measurements. Mean DR averaged across year was greater for N200 than for N0 (4.2 vs. 3.4 μg N2O-N kg dry soil−1 d−1) but did not differ among N sources. Our results suggest that choice of N fertilizer source in sandy soils is more important in controlling losses of N by leaching than by denitrification.

The Biology of Canadian Weeds. 137. Brassica napus L. and B. rapa L.

2008 ◽  
Vol 88 (5) ◽  
pp. 951-996 ◽  
Author(s):  
R. H. Gulden ◽  
S. I. Warwick ◽  
A. G. Thomas
Keyword(s):  
Brassica Napus ◽  
Herbicide Resistance ◽  
Eastern Canada ◽  
Brassica Napus L ◽  
Weed Biology ◽  
Herbicide Resistant ◽  
The Past ◽  
Transgene Escape ◽  
Feral Populations ◽  
Resistant Genotypes

Brassica napus and B. rapa are native to Eurasia. In Canada, these species are commonly referred to as volunteer canola, while feral populations of B. rapa are referred to as birdrape. Brassica napus and B. rapa have been grown commercially for their seed oil content in western Canada since the middle of the last century and volunteer populations are common in fields. Escaped populations of both species are also found along roadways, railways and in waste areas; however, only B. rapa is known to have naturalized, self-sustaining feral populations in these habitats in eastern Canada. Despite these escaped and feral populations, B. napus and B. rapa are mainly a concern in agricultural fields where their combined relative abundance has increased over the past few decades. In the mid 1990s, herbicide-resistant genotypes of B. napus were released for commercial production. Herbicide-resistance and the stacking of genes in volunteer populations conferring resistance to multiple herbicides have contributed to increased difficulties in controlling volunteer B. napus in some crops. However, yield loss resulting from volunteer populations is not well documented in Canada. Key words: Brassica napus, Brassica rapa, herbicide resistance, transgene escape, volunteer canola, weed biology

The Biology of Canadian Weeds. 111. Anthriscus sylvestris (L.) Hoffm

1999 ◽  
Vol 79 (4) ◽  
pp. 671-682 ◽  
Author(s):  
S. J. Darbyshire ◽  
R. Hoeg ◽  
J. Haverkort
Keyword(s):  
British Columbia ◽  
Key Words ◽  
Vegetative Reproduction ◽  
Old Fields ◽  
Eastern Canada ◽  
Weed Biology ◽  
Perennial Crops ◽  
Anthriscus Sylvestris ◽  
Disturbed Areas

Wild chervil, Anthriscus sylvestris (L.) Hoffm. (Apiaceae), is a weed of perennial crops, old fields, disturbed areas and roadsides. Introduced from Eurasia, it is widely naturalized in eastern Canada from Newfoundland to Ontario and at two sites in British Columbia. It is a monocarpic short-lived perennial, reproducing by seed and budding from the root crown. Dense populations achieved through vegetative reproduction can exclude most other vegetation. The rust, Puccinia pimpinellae subsp. pimpinellae, was detected on a population of wild chervil from Quebec. Key words: Wild chervil, Anthriscus sylvestris, weed biology

Root biomass and shoot to root ratios of perennial forage crops in eastern Canada

2002 ◽  
Vol 82 (4) ◽  
pp. 731-737 ◽  
Author(s):  
M. A. Bolinder ◽  
D. A. Angers ◽  
G. Bélanger ◽  
R. Michaud ◽  
M. R. Laverdière
Keyword(s):  
Root Biomass ◽  
Perennial Grass ◽  
Field Studies ◽  
Climatic Conditions ◽  
Grass Species ◽  
Eastern Canada ◽  
Forage Crops ◽  
Significant Difference ◽  
Peak Standing Crop ◽  
Perennial Legume

Shoot to root ratios (S:R) at peak standing crop are commonly used to estimate the annual crop residue C inputs to the soil from the root biomass left in the soil at harvest. However, root biomass has often been neglected in field studies and estimates of S:R for many commonly grown forage species are not available. Our objective was to determine root biomass and S:R of seven perennial grass species and two perennial legume species under eastern Canadian soil and climatic conditions. Root biomass in three soil layers (0–15, 15–30 and 30–45 cm) was measured shortly after the second harvest in the first (1995) and second (1996) year of production. Two harvests of aboveground DM were taken each year. The total root biomass (0–45 cm) in the second year of production (average of 1437 g m-2) was twice that measured in the first year of production (average of 683 g m-2). This temporal variation was mainly explained by the increase of root biomass in the 0- to 15-cm layer. The proportion of total root biomass (0–45 cm) in the 0- to 15-cm layer increased from 54 to 71% while that in the 15- to 30-cm layer decreased from 37 to 21%; the proportion of roots in the 30- to 45-cm layer remained constant at about 10% in both years. The S:R of alfalfa for the 0- to 15-cm depth was significantly higher than that for most of the grasses. No significant difference in S:R was observed among grass species. Recognizing that S:R may vary with locations and climatic conditions, our results suggest that average S:R of about 1.30 (values ranged from 1.01 to 1.72) in the first production year and 0.60 (values ranged from 0.43 to 0.87) in the second production year could be used as a first approximation to estimate the amount of root biomass left in the soil to a depth of 45 cm from forage crops in eastern Canada. The S:R of forage crops, particularly grasses, were lower than those of annual crops such as small-grain cereals and corn. Key words: Forage, annual C inputs, soil organic matter, root biomass, shoot to root ratios

Effect of nitrogen fertilizer on a kangaroo grass (Themeda australis) grassland

1974 ◽  
Vol 14 (69) ◽  
pp. 526 ◽  
Author(s):  
HJ Fisher
Keyword(s):  
Nitrogen Fertilizer ◽  
Dry Matter ◽  
New South ◽  
Perennial Grass ◽  
Low Fertility ◽  
Botanical Composition ◽  
Nitrogen Rate ◽  
South Wales ◽  
Cutting Frequency ◽  
High Level

Three rates of nitrogen fertilizer and a standard superphosphate dressing were applied to a Themeda australis grassland with and without broadcast seed of Dactylis glomerata. Two cutting frequencies were imposed and dry matter yields and botanical composition were measured. T. australis responded to nitrogen, but the response was not sufficient for it to predominate over other species, particularly Poa labillardieri, as it had done under low fertility conditions. P. labillardieri yields increased markedly with increasing nitrogen rate. D. glomerata, which established only where nitrogen fertilizer was applied, substantially reduced the increase in P. labillardieri at the high level of nitrogen. Cutting frequency affected botanical composition in degree but not in kind. Both P. labillardieri and D. glomerata yielded less, but T. australis yielded more under more frequent cutting. For pasture improvement in wetter parts of the southern tablelands of New South Wales, it is important to establish a perennial grass at the beginning of the programme to reduce the growth of the undesirable tussock. P. labillardieri.

Evaluation of terbacil-based herbicide treatments for hair fescue management in lowbush blueberry

2020 ◽  
pp. 1-29
Author(s):  
Scott N. White ◽  
Linshan Zhang
Keyword(s):  
Nova Scotia ◽  
Weed Management ◽  
Perennial Grass ◽  
Management Program ◽  
Industry Standard ◽  
Lowbush Blueberry ◽  
Herbicide Treatments ◽  
Grass Weed

Hair fescue is common tuft-forming perennial grass weed that reduces yields and hinders mechanical harvest in lowbush blueberry fields. PRE terbacil applications traditionally controlled hair fescue, but currently only provide suppression in most fields. Terbacil use has not, however, been evaluated in conjunction with other currently registered herbicides in lowbush blueberry. The objective of this research was to evaluate a range of terbacil-based herbicide treatments for hair fescue management in lowbush blueberry. The experiment was conducted at three lowbush blueberry fields in Nova Scotia, Canada. Spring non-bearing year terbacil applications (2000 g ai ha-1) exhibited variable efficacy on hair fescue with reduced total tuft density at one site and reduced flowering tuft density and flowering tuft inflorescence number at two sites. Suppression was limited to the year of application only. Terbacil followed by (fb) foramsulfuron (35 g ai ha-1) did not improve suppression. A terbacil tank mixture with glufosinate (750 ai ha-1), however, reduced flowering tuft density and flowering tuft inflorescence number at each site and reduced total tuft density at one site, suggesting improved suppression with terbacil+glufosinate relative to terbacil alone. Terbacil+glufosinate fb foramsulfuron gave additional reductions in total tuft density at two sites and reduced bearing year flowering tuft density at two sites, indicating that hair fescue suppression with this herbicide combination extends into the bearing year. Although less effective than the industry standard pronamide applications, terbacil+glufosinate or terbacil+glufosinate fb foramsulfuron could be used as part of a weed management program for hair fescue in lowbush blueberry.

THE BIOLOGY OF CANADIAN WEEDS. 83. Hypericum perforatum L.

1988 ◽  
Vol 68 (1) ◽  
pp. 149-162 ◽  
Author(s):  
C. W. CROMPTON ◽  
I. V. HALL ◽  
K. I. N. JENSEN ◽  
P. D. HILDEBRAND
Keyword(s):  
Hypericum Perforatum ◽  
Control Measures ◽  
Effective Control ◽  
Eastern Canada ◽  
Weed Biology ◽  
Lowbush Blueberry ◽  
Specific Strain ◽  
Hypericum Perforatum L ◽  
Low Levels ◽  
And Control

Hypericum perforatum L., St. John’s-wort is an introduced weed growing in waste places, roadsides, rangelands, pastures and similar habitats of Eastern Canada and British Columbia. It is poisonous to livestock causing a photosensitization in grazing animals with light-colored hair. In Canada, two introduced leaf-feeding beetles Chrysolina quadrigemina and C. hyperici have provided effective control. In Nova Scotia an endemic host-specific "strain" of Colletotrichum gloeosporioides generally maintained this weed at low levels, particularly in lowbush blueberry fields. It spreads both by seeds and vegetatively by rhizomes. Details related to its morphology, reproductive biology, responses to human manipulation, parasites and control measures are summarized.Key words: Hypericum perforatum, weed biology, review

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