scholarly journals Potential Role of Sequential Glufosinate and Foramsulfuron Applications for Management of Fescues (Festucaspp.) in Wild Blueberry

2017 ◽  
Vol 31 (1) ◽  
pp. 100-110 ◽  
Author(s):  
Scott N. White ◽  
Shanthanu Krishna Kumar
Keyword(s):  
Field Study ◽  
Seed Production ◽  
Potential Role ◽  
Seedling Recruitment ◽  
Seedling Emergence ◽  
Seed Viability ◽  
Early Spring ◽  
Seedling Mortality ◽  
Wild Blueberry

Sheep and hair fescue are perennial, tuft forming grasses that spread by seed and form dense sods in wild blueberry fields. These sods compete with the crop for resources and hinder harvest. Field and greenhouse studies were conducted in 2015 to evaluate 1) the effect of sequential glufosinate and foramsulfuron applications on suppression of fescues in the greenhouse and field, and 2) efficacy of glufosinate and foramsulfuron on fescue seedlings when applied at 2, 4, 6, and 8 wk after seedling emergence in the greenhouse. Glufosinate applications at 750 and 1,005 g ai ha−1followed by foramsulfuron application at 35 g ai ha−1reduced fescue leaf number and biomass relative to foramsulfuron application alone in the greenhouse. In the field study, fescue flowering tuft density, tuft inflorescence height, seed production, and seed viability were reduced by foramsulfuron alone, but there was a trend towards lower seed production and tuft height when fescues were treated with glufosinate at 1,005 g ha−1followed by foramsulfuron. Foramsulfuron caused low seedling mortality at all application timings evaluated, but glufosinate caused >90% mortality in seedlings when applied at 2, 4, 6, or 8 wk after seedling emergence. Our results suggest that sequential applications of these herbicides are less effective under field conditions relative to results obtained in the greenhouse, though burndown glufosinate applications may have a role in reducing fescue seedling recruitment. Additional research should be conducted to determine the effect of early spring and autumn glufosinate applications on fescue seedling recruitment and suppression of established fescue tufts with subsequent foramsulfuron applications.

scholarly journals Do applications of systemic herbicides when green fruit are present prevent seed production or viability of Alliaria petiolata (garlic mustard)?

2021 ◽  
pp. 1-17
Author(s):  
Leo Roth ◽  
José Luiz C. S. Dias ◽  
Christopher Evans ◽  
Kevin Rohling ◽  
Mark Renz
Keyword(s):  
Seed Production ◽  
Seed Viability ◽  
Early Spring ◽  
Alliaria Petiolata ◽  
Late Spring ◽  
Garlic Mustard ◽  
Viable Seed ◽  
Application Timing ◽  
Control Seed ◽  
Second Year

Garlic mustard [Alliaria petiolata (M. Bieb.) Cavara & Grande] is a biennial invasive plant commonly found in the northeastern and midwestern United States. Although it is not recommended to apply herbicides after flowering, land managers frequently desire to conduct management during this timing. We applied glyphosate and triclopyr (3% v/v and 1% v/v using 31.8% and 39.8% acid equivalent formulations, respectively) postemergence to established, second-year A. petiolata populations at three locations when petals were dehiscing, and evaluated control, seed production and seed viability. Postemergence glyphosate applications at this timing provided 100% control of A. petiolata by 4 weeks after treatment at all locations whereas triclopyr efficacy was variable, providing 38-62% control. Seed production was only reduced at one location, with similar results regardless of treatment. Percent seed viability was also reduced, and when combined with reductions in seed production, we found a 71-99% reduction in number of viable seed produced plant-1 regardless of treatment. While applications did not eliminate viable seed production, our findings indicate that glyphosate and triclopyr applied while petals were dehiscing is a viable alternative to cutting or hand-pulling at this timing as it substantially decreased viable A. petiolata seed production. Management Implications Postemergence glyphosate and triclopyr applications in the early spring to rosettes are standard treatments used to manage A. petiolata. However, weather and other priorities limit the window for management, forcing field practitioners to utilize more labor-intensive methods such as hand-pulling. It is not known how late in the development of A. petiolata these herbicides can be applied to prevent viable seed production. Since prevention of soil seedbank replenishment is a key management factor for effective long-term control of biennial invasive species, we hypothesized late spring foliar herbicide applications to second year A. petiolata plants when flower petals were dehiscing could be an effective management tool if seed production or viability is eliminated. Our study indicated that glyphosate applications at this timing provided 100% control of A. petiolata plants by 4 weeks after treatment at all locations, whereas triclopyr efficacy was inconsistent. Although both glyphosate and triclopyr decreased viable seed production to nearly zero at one of our three study locations, the same treatments produced significant amounts of viable seed at the other two locations. Our findings suggest late spring glyphosate and triclopyr applications should not be recommended over early spring applications to rosettes for A. petiolata management, as our late spring application timing did not prevent viable seed production, and may require multiple years of implementation to eradicate populations. Nonetheless, this application timing holds value in areas devoid of desirable understory vegetation compared to no management practices or mechanical management options including hand-pulling when fruit are present, as overall viable seed production was reduced to similar levels as these treatments.

Effects of disturbance and rabbit grazing on seedling recruitment of six mesic grassland species

1999 ◽  
Vol 9 (2) ◽  
pp. 145-156 ◽  
Author(s):  
Grant R. Edwards ◽  
Michael J. Crawley
Keyword(s):  
Seedling Recruitment ◽  
Plantago Lanceolata ◽  
Plant Cover ◽  
Seedling Emergence ◽  
Soil Disturbance ◽  
Seedling Mortality ◽  
Grassland Species ◽  
Rabbit Grazing ◽  
Plant Densities ◽  
Seed Sowing

AbstractSeeds of two grass (Arrhenatherum elatius and Festuca rubra), two herb (Plantago lanceolata and Rumex acetosa) and two legume (Lotus corniculatus and Trifolium repens) species were sown in summer 1995 at four densities (no seed, 1000, 10 000 and 50 000 seeds m−2) into an established rabbit-grazed grassland given factorial combinations of rabbit fencing (with and without fences) and soil disturbance (with and without cultivation). On plots where no seeds were sown, only the species with persistent seed banks (P. lanceolata, L. corniculatus and T. repens) showed enhanced seedling emergence in response to disturbance. In disturbed soil, seedling densities of all species increased with increasing density of sown seeds, the effects of which were still evident for plant cover 2 years after seed sowing. In undisturbed vegetation, A. elatius, F. rubra, P. lanceolata and R. acetosa showed increased seedling densities following seed sowing; but in each case, there was an upper asymptote to seedling recruitment, presumably due to microsite limitation. Rabbit grazing reduced seedling densities, with this reduction being more pronounced with disturbance than without. However, the effect of rabbit grazing did not persist for some species; seedling mortality of R. acetosa, P. lanceolata, L. corniculatus and T. repens was higher on plots without rabbit grazing, so that plant densities of these species in summer 1996 and plant cover in summer 1997 were greater on grazed plots. The results indicate interactions between soil disturbance, propagule availability and herbivory, rather than disturbance alone, will play an important role in controlling seedling recruitment and species habitat distributions in grasslands.

Ecology of Nassella neesiana, Chilean needle grass, in pastures on the Northern Tablelands of New South Wales. II. Seedbank dynamics, seed germination, and seedling recruitment

2003 ◽  
Vol 54 (6) ◽  
pp. 621 ◽  
Author(s):  
M. R. Gardener ◽  
R. D. B. Whalley ◽  
B. M. Sindel
Keyword(s):  
Seed Production ◽  
Seedling Recruitment ◽  
Seedling Survival ◽  
New South ◽  
Seedling Emergence ◽  
New South Wales ◽  
Separate Experiment ◽  
Bare Ground ◽  
Total Percentage ◽  
South Wales

This is the second in a series of papers investigating the ecology of Nassella neesiana (Trin. & Rupr.) Barkworth (Chilean needle grass) in pastures on the Northern Tablelands of New South Wales. The reasons for its success as a pasture weed are discussed. Nassella neesiana has a large and persistent soil seedbank. After 3 years without seed input, the seedbank declined from 4676 to 1323 seeds/m2. When an exponential decay curve was fitted to the data it was predicted that the seedbank would reach 10 seeds/m2 after 12.4 years. When seed production was large in 1996, 41.6% of seeds produced were incorporated into the seedbank, whereas in 1995 and 1997 the smaller seed production was only sufficient to maintain seedbank numbers. Furthermore, it is likely that the seedbank numbers were underestimated because they did not include basal cleistogenes. In a separate experiment, basal cleistogenes were found to contribute a further 20% to the seedbank.A small proportion of the viable seeds in a natural seedbank emerged from bare ground over 2 years. Seedling survival was high, with 78% of those germinating from bare ground surviving for at least 20 months. Several experiments were designed to investigate the mechanisms of this germination and survival. It appears that the seeds of N. neesiana have an after-ripening requirement of between 3 months and 1 year for maximum germination. Lemma removal from seeds stored for 8 months increased germination from 49 to 82%. The rate of germination and the total percentage of seeds germinating also increased with time of burial in the ground. Of seeds that had been buried for 2 years, 90% germinated after laboratory incubation compared with 48% of seeds stored in the laboratory as controls. Depth of seed burial appears to affect seedling emergence and survival. A smaller number of seedlings emerged from 0–10 mm and they had lower survival than those from seed buried at 10–20 mm.

Ecological Studies of the Endangered Rutidosis leptorrhynchoides. II. Patterns of Seedling Emergence and Survival in a Native Grassland

1995 ◽  
Vol 43 (1) ◽  
pp. 13 ◽  
Author(s):  
JW Morgan
Keyword(s):  
Soil Moisture ◽  
Seedling Recruitment ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Moisture Stress ◽  
Seedling Mortality ◽  
Themeda Triandra ◽  
Established Plant ◽  
Survival And Growth ◽  
Growth Of Seedlings

The emergence, survival and growth of seedlings of the endangered Rutidosis leptorrhynchoides F.Muell. were followed in a Themeda triandra grassland during 1991 and 1992. The effect of summer irrigation on seedling survival was also investigated. Seedling emergence occurred in both years within 2 weeks of the 'autumn break' when soil moisture rose above 20%. Ninety percent of emergence was observed within 4 weeks of the onset of germination and 87% of seedlings were within 20 cm of an established plant. No emergence was observed after 8 weeks. Thirteen percent of the 1991 cohort survived for 14 months. Mortality of most seedlings (63%) was attributed to soil moisture stress in summer. Small seedlings (Ͱ4 3 leaves) were no more susceptible to drought than larger seedlings. Seventy two percent of the 1991 cohort produced four leaves before subsequently dying. In 1992, however, most early seedling mortality was amongst cotyledonary seedlings. No seedlings flowered in their first year. Above-ground growth was slow and by 14 months, 60% of surviving seedlings had seven or fewer live leaves. Irrigation in a year of below-average rainfall had no significant effect on the survival and growth of seedlings. This suggests that seedling recruitment is not restricted to climatically favourable years (i.e. is not episodic) but rather, is potentially on-going provided suitable microsites are available for seedling survival.

Ecological Studies of the Endangered Rutidosis Leptorrhynchoides .I. Seed Production, Soil Seed Bank Dynamics, Population Density and Their Effects on Recruitment

1995 ◽  
Vol 43 (1) ◽  
pp. 1 ◽  
Author(s):  
JW Morgan
Keyword(s):  
Population Density ◽  
Seed Production ◽  
Seed Bank ◽  
Seedling Recruitment ◽  
Fire Regime ◽  
Seedling Survival ◽  
Soil Seed Bank ◽  
Seedling Emergence ◽  
Seed Bank Dynamics ◽  
The Impact

The seasonal dynamics of the soil seed bank of Rutidosis leptorrhynchoides F.Muell. were studied by the seedling emergence technique. Seed longevity in soil was quantified in a seed burial and retrieval experiment. The importance of annual seed production to recruitment was also determined over a 2-year-period, as was the impact of conspecific neighbour density on seed production per inflorescence. Rutidosis leptorrhynchoides appears to form a transient seed bank with little capacity to store germinable seeds in the soil from year to year. No seedlings were observed in soil sampled after the autumn germination pulse and no viable seed was present in the soil within 16 weeks of burial. The rate of seed loss was similar when seed was buried under all intact grassland canopy and in 0.25m2 canopy gaps. It appears that most seeds simply rot in moist soil or are predated by soil invertebrates. Seedling recruitment was at least 15 times greater in plots where natural seed input occurred than where it was curtailed. Less than 10% of seed shed resulted in seedling emergence. It is suggested that recruitment in the large populations studied was limited by germination rather than by microsite availability for seedling survival. Population density had an impact on seed production with sparsely distributed individuals producing fewer seeds per inflorescence than plants from denser colonies, although there was much variation. Sparse plants produced significantly fewer seeds per inflorescence than hand crosspollinated heads suggesting reduced pollinator efficacy in these colonies relative to larger colonies where there was no such difference. Rutidosis leptorrhynchoides is dependent on the maintenance of the standing population for recruitment. Any factors that influence flowering and subsequent seed production will limit the ability of the species to regenerate. Over sufficient time, this could lead to the localised extinction of the species and may explain why R. leptorrhynchoides has failed to reappear in remnants where a suitable fire regime has been re-implemented after a period of management unfavourable to the survival, flowering and regeneration of this species.

scholarly journals Longevidad y germinación de semillas de Syagrus romanzoffiana (Arecaceae) y sus implicaciones ecológicas

2015 ◽  
Vol 63 (2) ◽  
pp. 333 ◽  
Author(s):  
Túlio Gabriel Soares Oliveira ◽  
Anderson Cleiton José ◽  
Leonardo Monteiro Ribeiro ◽  
José Marcio Rocha Faria
Keyword(s):  
Seed Bank ◽  
Soil Seed Bank ◽  
Seedling Emergence ◽  
Seed Viability ◽  
Palm Tree ◽  
Forest Fragment ◽  
Seedling Mortality ◽  
Viable Seeds ◽  
One Year ◽  
Syagrus Romanzoffiana

<strong><em>Syagrus romanzoffiana</em> is a palm tree native and widely distributed of South America.</strong> <strong>The present study investigated the longevity and germination of the buried seeds of this species in an experimental seed bank.</strong> <strong>Laboratory germination and</strong> <strong>viability tests were performed for comparison with field results. Pyrenes (seeds enclosed by the endocarp) were buried in a forest fragment edge in July (dry season) in July 2012 and exhumed monthly during one year, for the assessment of water content</strong> <strong>and percentage of germinated and viable seeds.</strong> <strong>Germination tests</strong> <strong>were conducted in a Mangelsdorf-type germinator at 30°C under constant light and the viability was </strong><strong>assessed by the tetrazolium test. An additional sample of</strong> <strong>pyrenes was buried to evaluate the percentage of seedling emergence and survival. Climatic</strong> <strong>and soil moisture</strong> <strong>data</strong> <strong>were recorded.</strong> <strong>In the laboratory, the pyrenes were stored for one year in a temperature-controlled room at 20ºC and 75% (±10%) relative air humidity to assess changes in the percentage of germination and viability over time.</strong> <strong>In the field, a reduction in seed viability</strong> <strong>was observed over the study period, with a total loss of viability of non-germinated seeds at seven months after burial.</strong> <strong>The maximum germination (close to 26%) was observed in the samples that were exhumed between five and seven months after burial. In the field, seedling emergence did not exceed 10% and seedling mortality was not observed. The percentages of germination and of viable seeds decreased both in burial and stored seeds. The stored seeds maintained viability at up to six months, with marked reduction thereafter. After the germination tests (four months) in the laboratory, all of the remaining seeds were nonviable. The ecological, physiological</strong> <strong>and reproductive characteristics of the species are discussed, and we concluded that</strong> <strong><em>S. romanzoffiana</em></strong> <strong>seeds have short longevity after imbibition, and low potential for soil seed bank formation.</strong>

Postfire Demography of the Wet-Mallee Eucalyptus luehmanniana F Muell (Myrtaceae)

1991 ◽  
Vol 39 (5) ◽  
pp. 459 ◽  
Author(s):  
SJ Davies ◽  
PJ Myerscough
Keyword(s):  
Water Availability ◽  
Seedling Recruitment ◽  
Seedling Emergence ◽  
Seed Viability ◽  
Experimental Methods ◽  
Low Levels ◽  
Seed Fall ◽  
Experimental Plots ◽  
Mature Population ◽  
Growth And Reproduction

The post-fire demography of Eucalyptus luehmanniana, a wet-mallee eucalypt restricted to the Sydney region, was studied by descriptive and experimental methods. Patterns of growth and reproduction were related to time since the last fire for 15 populations burned from 2 to 24 years previously. After fire, mature individuals (clumps) resprout from subterranean lignotuberous buds producing numerous narrow stems. Resprouted clumps flower within 2-4 years and fruit within 5-6 years of the last fire. Fruits accumulate in the canopy with increasing time, up to at least 24 years since fire. Measurements from one reproductively mature population showed that there is a low level of seed-fall below the canopy (0.98 seeds m-2 day-1) in the absence of fire. Recruitment without fire appears unlikely due to a combination of factors: low seed viability (34.9%, s.e. = 5.3), low levels of field emergence, no soil-stored seed, and a high proportion (86.9%, s.e. = 3.4) of seed failing enclosed in capsules. Canopy-stored seed is released en masse following fire. Three factors potentially influencing the recruitment of E. luehmanniana seedlings, fire-related effects, water availability and protection of developing seedlings from animals, were investigated experimentally in the field. Seedling emergence was uniformly low (2.2-2.6%), and not significantly increased on burned plots, caged plots, or water-added plots alone. In one experiment, plots both burned and caged had significantly higher emergence. Mortality in all experimental plots was 100% within 6 months. Seedling recruitment of E. luehmanniana will not occur following all fires, and will depend on the coincidence of fire with suitable post-fire conditions.

Effects of Herbicides on Grass Seed Production and Downy Brome (Bromus tectorum)

1997 ◽  
Vol 11 (4) ◽  
pp. 644-648 ◽  
Author(s):  
Tom D. Whitson ◽  
Mark E. Majerus ◽  
Reginald D. Hall ◽  
Jay D. Jenkins
Keyword(s):  
Seed Production ◽  
Seed Yield ◽  
Field Experiments ◽  
Seed Viability ◽  
Early Spring ◽  
Perennial Grasses ◽  
Downy Brome ◽  
Cool Season ◽  
Grass Seed ◽  
Seed Harvest

Control of downy brome in cool-season perennial grasses grown for seed production must be done prior to seed harvest, because downy brome seeds cannot be separated from cool-season grass seeds. Field experiments were conducted near Powell, WY, and Bridger, MT, to evaluate several herbicides for control of downy brome from 1992 through 1994 in western wheatgrass, slender wheatgrass, beardless wild rye, thickspike wheatgrass, and meadow bromegrass. When fall-applied, only metribuzin at 0.4 kg/ha and oxyfluorfen plus metribuzin at 1.1 plus 0.3 kg/ha controlled 98 and 95% of the downy brome, respectively, without affecting grass seed viability or seed yield. Early spring applications of paraquat at 0.8 kg/ha controlled 100% of the downy brome, but suppressed perennial grasses. Glyphosate applied in early spring at 0.3 kg/ha controlled 48% of the downy brome, but suppressed perennial grasses. Seed yield reductions occurred when thickspike wheatgrass and meadow brome were treated with glyphosate at 0.3 kg/ha.

Seedling recruitment of the exotic grass Andropogon gayanus (Poaceae) in northern Australia

2005 ◽  
Vol 53 (3) ◽  
pp. 243 ◽  
Author(s):  
Trish A. Flores ◽  
Samantha A. Setterfield ◽  
Michael M. Douglas
Keyword(s):  
Seed Production ◽  
Seedling Recruitment ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Perennial Grass ◽  
Effective Control ◽  
Northern Australia ◽  
Wet Season ◽  
Soil Cultivation ◽  
Andropogon Gayanus

Andropogon gayanus Kunth. (Gamba grass), a tall perennial grass from Africa, is invading savanna ecosystems in northern Australia. This study investigated A. gayanus recruitment to determine the habitats at risk of invasion and to provide recommendations for its management. A. gayanus is able to establish and spread into new areas because of its high seed production (averaging 70 000 seeds m–2) and ability to establish across a range of habitats: from open woodlands on relatively dry lateritic soils to the more closed forests on black soil of the floodplain margins. Seedling emergence occurred in the absence of soil cultivation, although soil cultivation did increase emergence in the wetter habitats (Melaleuca uplands and floodplain margins). Seedling survival was high in the savanna (~90%) but low in the wetter habitats owing to wet-season inundation. A seed longevity trial based on burying seed in the field and retrieving between 1 and 12 months after burial showed that less than 1% of seeds survived in the seedbank after 12 months. Effective control programs are needed immediately because of the vast area and range of habitats in northern Australia that could potentially be invaded by A. gayanus. Management that can limit site disturbance and seed production, and can incorporate follow-up control for one to two years, should be an important part of an A. gayanus control strategy.

scholarly journals Role of re-seeding and seedling recruitment for sustainable Lotus corniculatus based pastures in dry hill and high country

1994 ◽  
pp. 139-142
Author(s):  
W.J. Fraser ◽  
S.C. Ogden ◽  
R.F. Woodman ◽  
W.L. Lowther
Keyword(s):  
Field Experiments ◽  
Seedling Recruitment ◽  
Seedling Emergence ◽  
Lotus Corniculatus ◽  
Climatic Conditions ◽  
Birdsfoot Trefoil ◽  
The South ◽  
Plant Populations ◽  
Stand Management

Birdsfoot trefoil (Lotus comiculatus L.) is a species with considerable potential for hill and high country of the South Island; however, difficulties in maintaining satisfactory stands due to problems with persistence have been reported. Plant recruitment through natural reseeding is considered a necessary tool for the maintenance and improvement of birdsfoot trefoil stands in the USA, but research which investigates the role of soil seedbanks, seedling recruitment and stand management for improving the persistence of birdsfoot trefoil in the drier hill and high country of the South Island of New Zealand is limited. Two field experiments in the dry hill and high country of Otago monitored changes in stand populations and seedling emergence of birdsfoot trefoil under differing grazing management. At Ardlui Station on the Coastal Otago Plateau, seedling emergence was greatest in autumn rather than spring after spelling over the flowering period. Despite considerable numbers of autumn seedlings (128 seedlings/m2), less than 1 seedling/m2 survived to contribute to the stand after 12 months. Plant populations did,however increase in 199l/92 following adequate rainfall in the previous autumn. Spring emerged seedlings did not survive through summer. At Omarama Station in the southern Mackenzie Basin, plant populations of birdsfoot trefoil continued to decline despite the presence of seedlings in spring and autumn. Results imply that natural reseeding cannot be relied upon to improve birdsfoot trefoil plant populations unless favourable climatic conditions prevail during spring or autumn. Keywords: establishment, Lotus corniculatus, management, natural reseeding, persistence, seedling recruitment, soil seedbanks, survival

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