Seedbank Dynamics of Two Swallowwort (Vincetoxicum) Species

2017 ◽  
Vol 10 (2) ◽  
pp. 136-142 ◽  
Author(s):  
Antonio DiTommaso ◽  
Lindsey R. Milbrath ◽  
Scott H. Morris ◽  
Charles L. Mohler ◽  
Jeromy Biazzo
Keyword(s):  
United States ◽  
Management Strategy ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Growing Season ◽  
First Year ◽  
Northeastern United States ◽  
The Third ◽  
Viable Seeds ◽  
Filled Seeds

Pale swallowwort and black swallowwort are European viny milkweeds that have become invasive in many habitats in the northeastern United States and southeastern Canada. A multiyear seedbank study was initiated in fall 2011 to assess annual emergence of seedlings and longevity of seeds of pale swallowwort and black swallowwort at four different burial depths (0, 1, 5, and 10 cm) over 4 yr. One hundred swallowwort seeds were sown in seed pans buried in individual pots, and emerged seedlings were counted and removed from May through September each year. A subset of seed pans was retrieved annually in October, and recovered seeds were counted and tested for viability. The majority of seedling emergence occurred during the first year (92% in 2012), and no new seedlings emerged in the third (2014) or fourth (2015) years. Pale swallowwort had relatively poor emergence at sowing depths of 0 cm (11%), 5 cm (6%), and 10 cm (0.05%—only one seedling), while 37% of pale swallowwort seeds emerged at 1 cm. The larger-seeded black swallowwort was more successful, with two-thirds of all sown seeds emerging at depths of 1 cm (71%) and 5 cm (66%), and 26% emerging at 10 cm. Only 16% of the surface-sown black swallowwort emerged. A large portion of the seeds that germinated at 10 cm, as well as at 5 cm for pale swallowwort, died before reaching the soil surface. Of filled seeds that were recovered in 2012 (black swallowwort at the 0-cm depth), 66% were viable. No viable seeds were recovered after the second growing season. Seeds recovered following the third year had become too deteriorated to accurately assess. Swallowwort seeds do not appear to survive more than 2 yr in the soil, at least in our experiment, suggesting that the elimination of seed production over 3 yr will exhaust the local seedbank. Seeds would need to be buried at least 10 cm for pale swallowwort but more than 10 cm for black swallowwort to prevent seedling emergence. Burial of swallowwort seeds as a management strategy may, however, only be practical in natural areas where high swallowwort densities occur.

Changes with time in the germination of buried scentless chamomile (Matricaria perforata Mérat) seeds

1995 ◽  
Vol 75 (1) ◽  
pp. 277-281 ◽  
Author(s):  
G. G. Bowes ◽  
A. G. Thomas ◽  
L. P. Lefkovitch
Keyword(s):  
Seed Bank ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Growing Season ◽  
Early Spring ◽  
First Year ◽  
Temperature Regimes ◽  
Buried Seed ◽  
Second Year ◽  
Persistent Seed Bank

Change with time in the germination of scentless chamomile (Matricaria perforata Mérat) seeds was investigated. Seeds were placed in nylon net bags, buried 7 cm deep in soil, exhumed at monthly intervals for 2 yr and allowed to germinate in temperature regimes of 10/2 °C, 20/5 °C, 25/10 °C and 35/20 °C (16/8 h), simulating temperatures found during early spring or late fall, spring or fall, summer and mid-summer on the soil surface, respectively. Exhumed and refrigerator-stored (2 °C) check seeds exhibited no yearly dormancy/nondormancy germination cycle, but mortality of buried seed increased to 36%, after 10 mo in contrast with that of the check seeds which remained low for two years. Light was required for germination during the first year but was not required for a portion of the seed during the second year. The retention of viability in buried seed explains the persistent seed bank and seedling emergence throughout the growing season when moisture and temperature are nonlimiting. Key words: Seed burial, germination, Matricaria perforata Mérat

Effect of length of growing season on development of hard seeds in yellow serradella and their subsequent softening at various depths of burial

1999 ◽  
Vol 50 (7) ◽  
pp. 1211 ◽  
Author(s):  
C. K. Revell ◽  
G. B. Taylor ◽  
P. S. Cocks
Keyword(s):  
Soil Surface ◽  
Growing Season ◽  
First Year ◽  
Variable Effect ◽  
Softening Mechanism ◽  
Hard Seeds ◽  
Before And After ◽  
Viable Seeds ◽  
A Site ◽  
Seed Yields

Effects of withholding water at 4 (W4) and 8 (W8) weeks after commencement of flowering on seed development in 2 accessions of yellow serradella (Ornithopus compressus L.), cv. Avila and accession GEH72-1A, were investigated in swards at a site near Perth, Western Australia. Softening of resulting hard seeds during the following summer and autumn was then studied in newly ripened pods placed at the soil surface, and at depths of 0.5 and 2 cm in the soil at Merredin in the first week of January. Proportions of soft seeds were determined in the original seed populations and in pods taken from the field in March and June. In 2 further treatments, proportions of soft seeds were determined in June in (i) pods that had been at the soil surface until they were buried at 2 cm in March, and (ii) in pods that had been buried at 2 cm until March, when they were returned to the soil surface. Seed yields from W4 were about 35% of those from W8 owing to reductions in pod numbers (partly as a result of more flower shedding in W4), number of seeds per pod, and seed size. Developing seeds became germinable between 21 and 29 days after anthesis when seed dry weights were between 0.9 and 1.4 mg, which was about the same time that they developed the capacity for seed coat impermeability. Viability of hard seeds was almost 100% from W8 but only 65% from the W4 treatments. Less than 5% of the newly ripened viable seeds were soft in any of the treatments. Length of growing season had no effect on seed softening at the soil surface and only a relatively small and variable effect on softening in buried pods. At the June sampling, up to 16% of Avila and 5% of GEH72-1A seeds had softened at the soil surface. Burial of pods increased proportions of soft seeds up to 85% in Avila and 53% in GEH72-1A. Whereas most of the seed softening in Avila occurred before March, similar amounts of softening occurred before and after the March sampling in GEH72-1A. Burial of pods in March increased seed softening by June in GEH72-1A but reduced softening in Avila, whereas transfer of buried pods to the soil surface in March had the reverse effect. This seed softening behaviour is explained in terms of the 2-stage seed softening mechanism. Burial of newly ripened seeds by tillage or stock trampling during the first summerŒautumn appears a feasible management option for improving first year regeneration in at least the softer seeded accessions of yellow serradella.

Decline of Weed Seeds and Seedling Emergence Over Five Years as Affected by Soil Disturbances

Weed Science ◽  
1990 ◽  
Vol 38 (6) ◽  
pp. 504-510 ◽  
Author(s):  
Grant H. Egley ◽  
Robert D. Williams
Keyword(s):  
Seedling Emergence ◽  
Soil Surface ◽  
First Year ◽  
Weed Species ◽  
Native Seed ◽  
Seed Population ◽  
Soil Disturbances ◽  
Viable Seeds ◽  
Prickly Sida ◽  
Weed Emergence

Weed emergence and viable weed seed numbers were determined in field plots during a 5-yr period where reseeding was prevented. Known numbers of seeds of seven weed species were added to the native seed population at the beginning of the study. Plots were nontilled or tilled to depths of 0, 5, 10, and 15 cm early in the spring of each year. Velvetleaf, spurred anoda, hemp sesbania, morningglory species, and pigweed species emergence was significantly greater from the nontilled plots during the first year after seeds were added to the native seed population. Tillage, regardless of depth, reduced weed emergence during the first year where seeds were added to the plots but had no effect on emergence from plots where no seeds were added. Tillage during the second through the fifth year did not affect emergence regardless of the addition of seeds. of the 5-yr emergence totals, 61 to 88% of all weeds in all plots emerged during the first year and 9 to 23% emerged during the second year. The 5-yr decline rate for emergence of all weeds was exponential. Viable seeds of prickly sida, spurges, and pigweeds in the nontilled plots declined from 590, 1531, and 4346 m−2, respectively, to zero by the third year. Tillage did not affect the decline. However, weed emergence in the field indicated that a few (1.0 to 5.6 m−2) seeds of those weeds were still viable after 3 yr. In nontilled plots, many recently added seeds were on or near the soil surface and germinated during the first year. Tillage moved many seeds to sites that were unfavorable for germination and emergence during the first year.

scholarly journals A linuron-free weed management strategy for carrots

2019 ◽  
Vol 33 (03) ◽  
pp. 464-474
Author(s):  
Tessa de Boer ◽  
Peter Smith ◽  
Kevin Chandler ◽  
Robert Nurse ◽  
Kristen Obeid ◽  
...  
Keyword(s):  
Effective Dose ◽  
Pest Management ◽  
Weed Management ◽  
Management Strategy ◽  
Seedling Emergence ◽  
Growing Season ◽  
Field Trials ◽  
Organic Soils ◽  
Biologically Effective Dose ◽  
And Control

AbstractThe development of a linuron-free weed management strategy for carrot production is essential as a result of the herbicide reevaluation programs launched by the Pest Management Regulatory Agency in Canada for herbicides registered before 1995 and the discovery of linuron-resistant pigweed species in Ontario. Field trials were conducted in one of Ontario’s main carrot-growing regions on high organic soils in 2016 and 2017. Pigweed species seedlings were effectively controlled with PRE treatments of prometryn, pendimethalin, S-metolachlor, or glufosinate. POST treatments of pyroxasulfone and metribuzin followed by predetermined biologically effective dose (≥90% control of pigweed seedlings) of acifluorfen, oxyfluorfen, fluthiacet-methyl, and fomesafen achieved excellent crop selectivity and commercially acceptable pigweed species seedling control under field conditions. Carfentrazone-ethyl or fomesafen applied PRE severely reduced seedling emergence and yield in the wet growing season of 2017. This study demonstrated clearly that an alternative linuron-free strategy can be developed for carrots. The strategy of exploring the potential to use the biologically effective dose of selected herbicides to achieve crop selectivity and control of pigweed species seedlings was verified.

Seed softening, imbibition time, and seedling establishmentin yellow serradella

2002 ◽  
Vol 53 (9) ◽  
pp. 1011 ◽  
Author(s):  
G. B. Taylor ◽  
C. K. Revell
Keyword(s):  
Marked Effect ◽  
Soil Surface ◽  
First Year ◽  
Large Numbers ◽  
Buried Seeds ◽  
Ornithopus Compressus ◽  
Intermediate Time ◽  
Softening Process ◽  
Viable Seeds ◽  
The Times

The first (preconditioning) and final stages of seed softening were studied over a 4-year period in 4 lines of yellow serradella (Ornithopus compressus L.): cvv. Santorini and Charano, and accessions GEH72-1A and GRC5045-2-2. Pods grown in 1997 were collected in December (start of summer) and placed on the soil surface or buried at a depth of 1 cm. Measurements of seed softening between years were made from pod samples removed in June each year. The progress of preconditioning and seed softening within the first 3 years was determined from samples taken at the end of February. Numbers of soft and viable seeds were determined from each sampling. Preconditioned seeds were identified by subjecting seeds to 7 gradual diurnal temperature cycles of 48/15°C in darkness before testing for permeability. Seed softening was markedly accelerated by pod burial in all 4 lines, with most buried seeds of GEH72-1A and Santorini softening during the first year. Seed softening was slower in GRC5045-2-2 and Charano, approaching a constant annual rate over the 4 years of the experiment. Despite this marked effect of burial the differences between lines in rates of softening of buried seeds were sufficient to have important implications for persistence under some management systems. Most seeds of all lines softened between February and June, indicating that shallow pod burial could be delayed in these lines until at least the end of February to promote the final stage of seed softening. Although large numbers of seeds of GEH72-1A and GRC5045-2-2 had preconditioned at the soil surface by the end of February, few went on to complete the softening process by June, when most had lost their preconditioned state. Treatment at 48/15°C was less successful in identifying preconditioned seeds of Santorini and Charano. Rates of imbibition differed markedly between lines. Most soft seeds of GEH72-1A and GRC5045-2-2 imbibed within days, whereas they took weeks in Santorini and an intermediate time in Charano. Seedling age distributions in the 4 lines in June closely reflected the times their soft seeds took to imbibe in the laboratory. Imbibition time can be an important germination regulating mechanism having implications that may be either favourable or unfavourable depending on rainfall distribution around the break of season and the system of management.

Impact of Clipping Timing on Japanese Hedgeparsley (Torilis japonica) Seed Production and Viability

2014 ◽  
Vol 7 (3) ◽  
pp. 511-516
Author(s):  
Mark J. Renz ◽  
R. Menyon Heflin
Keyword(s):  
United States ◽  
Seed Production ◽  
Management Strategy ◽  
Invasive Plant ◽  
Vegetative Stage ◽  
Effective Management ◽  
Viable Seed ◽  
Torilis Japonica ◽  
Forested Areas ◽  
Viable Seeds

AbstractJapanese hedgeparsley is a biennial plant that invades roadsides, rights-of way, and forested areas in the midwestern United States. Interest in managing populations by mechanical or hand-clipping techniques exists, but no information is available on the appropriate timing to maximize mortality and prevent the production of viable seed. To assess that, we applied clipping treatments at five periods throughout the summer to three Japanese hedgeparsley populations in southern Wisconsin and measured the number and viability of seeds produced by each plant during the year of treatment and the survival of plants clipped. Japanese hedgeparsley plants began producing seed by mid-July, but production was not maximized until early August. Viable seeds were not produced until early or mid-August, coinciding with the presence of ripened brown fruit. Clipping at any timing resulted in > 95% mortality by the fall of the treatment year. All plants that resprouted were in the vegetative stage when clipped, and no plants survived the following year. Results indicate that clipping Japanese hedgeparsley plants when they are in a reproductive phase before fruit turns brown is an effective management strategy for this invasive plant.

scholarly journals Weed Management Practices for Organic Production of Trailing Blackberry, II. Accumulation and Loss of Biomass and Nutrients

HortScience ◽  
2014 ◽  
Vol 49 (1) ◽  
pp. 35-43 ◽  
Author(s):  
Renee H. Harkins ◽  
Bernadine C. Strik ◽  
David R. Bryla
Keyword(s):  
Weed Control ◽  
Weed Management ◽  
Management Strategy ◽  
Organic Production ◽  
Nutrient Concentrations ◽  
First Year ◽  
The Third ◽  
Leaf Nutrient Concentrations ◽  
Hand Weeding ◽  
The Impact

A study was conducted in western Oregon to assess the impact of cultivar and weed management strategy on accumulation and loss of plant biomass and nutrients during the first 3 years of establishment when using organic fertilizer. The study was conducted in trailing blackberry (Rubus L. subgenus Rubus Watson) planted in May 2010 and certified organic in May 2012. Treatments included two cultivars, Marion and Black Diamond, each with either no weed control after the first year after planting or with weeds managed by hand-weeding or the use of weed mat. Each treatment was amended with organically approved fertilizers at pre-plant and was drip-fertigated with fish emulsion each spring. Most primocane leaf nutrient concentrations were within the range recommended for blackberry. However, leaf nitrogen (N) was low in ‘Black Diamond’, especially when grown without weed control, whereas leaf boron (B) was low in all treatments. In many cases, leaf nutrient concentrations were affected by cultivar and weed management in both the primocanes and the floricanes. The concentration of several nutrients in the fruit differed between cultivars, including calcium (Ca), magnesium (Mg), sulfur (S), B, and zinc (Zn), but only fruit Ca was affected by weed management and only in ‘Marion’. In this case, fruit Ca was higher when the cultivar was grown with weed mat than with hand-weeding or no weeding. Total biomass production of primocanes increased from an average of 0.3 t·ha−1 dry weight (DW) during the first year after planting to 2.0 t·ha−1 DW the next year. Plants were first cropped the third year after planting and gained an additional 3.3 t·ha−1 DW in total aboveground biomass (primocanes, floricanes, and fruit) by the end of the third season. Fruit DW averaged 1.4 t·ha−1 in non-weeded plots, 1.9 t·ha−1 in hand-weeded plots, and 2.3 t·ha−1 in weed mat plots. Biomass of senesced floricanes (removed after harvest) averaged 3.2 t·ha−1 DW and was similar between cultivars and among the weed management treatments. ‘Marion’ primocanes accumulated a higher content of N, phosphorus (P), potassium (K), Mg, S, iron (Fe), B, copper (Cu), and aluminum (Al) than in ‘Black Diamond’. Weeds, however, reduced nutrient accumulation in the primocanes in both cultivars, and accumulation of nutrients was greater in the floricanes than in the previous year’s primocanes. Total nutrient content declined from June to August in the floricanes, primarily through fruit removal at harvest and senescence of the floricanes after harvest. Depending on the cultivar and weed management strategy, nutrient loss from the fruit and floricanes averaged 34 to 79 kg·ha−1 of N, 5 to 12 kg·ha−1 of P, 36 to 84 kg·ha−1 of K, 23 to 61 kg·ha−1 of Ca, 5 to 15 kg·ha−1 of Mg, 2 to 5 kg·ha−1 of S, 380 to 810 g·ha−1 of Fe, 70 to 300 g·ha−1 of B, 15 to 36 g·ha−1 of Cu, 610 to 1350 g·ha−1 of manganese (Mn), 10 to 260 g·ha−1 of Zn, and 410 to 950 g·ha−1 of Al. Overall, plants generally accumulated (and lost) the most biomass and nutrients with weed mat and the least with no weed control.

scholarly journals Are biogenic emissions a significant source of summertime atmospheric toluene in rural Northeastern United States?

2008 ◽  
Vol 8 (3) ◽  
pp. 12283-12311 ◽  
Author(s):  
M. L. White ◽  
R. S. Russo ◽  
Y. Zhou ◽  
J. L. Ambrose ◽  
K. Haase ◽  
...  
Keyword(s):  
United States ◽  
Loblolly Pine ◽  
Seasonal Pattern ◽  
Warm Season ◽  
Growing Season ◽  
Emission Rates ◽  
Industrial Emissions ◽  
Northeastern United States ◽  
Mixing Ratios ◽  
Fuel Evaporation

Abstract. Summertime atmospheric toluene enhancements at Thompson Farm in the rural northeastern United States were unexpected and resulted in a toluene/benzene seasonal pattern that was distinctly different from that of other anthropogenic volatile organic compounds. Consequentially, three hydrocarbon sources were investigated for potential contributions to the enhancements during 2004–2006. These included: 1) increased warm season fuel evaporation coupled with changes in reformulated gasoline (RFG) content to meet U.S. EPA summertime volatility standards, 2) local industrial emissions and 3) local vegetative emissions. The contribution of fuel evaporation emission to summer toluene mixing ratios was estimated to range from 16 to 30 pptv d−1, and did not fully account for the observed enhancements (20–50 pptv) in 2004–2006. Static chamber measurements of alfalfa, a crop at Thompson Farm, and dynamic branch enclosure measurements of loblolly pine trees in North Carolina suggested vegetative emissions of 5 and 12 pptv d−1 for crops and coniferous trees, respectively. Toluene emission rates from alfalfa are potentially much larger as these plants were only sampled at the end of the growing season. Measured biogenic fluxes were on the same order of magnitude as the influence from gasoline evaporation and industrial sources (regional industrial emissions estimated at 7 pptv d−1) and indicated that local vegetative emissions make a significant contribution to summertime toluene enhancements. Additional studies are needed to characterize the variability and factors controlling toluene emissions from alfalfa and other vegetation types throughout the growing season.

Potential for Preseason Herbicide Application to Prevent Weed Emergence in the Subsequent Growing Season. 1. Identification and Evaluation of Possible Herbicides

2004 ◽  
Vol 18 (2) ◽  
pp. 228-235 ◽  
Author(s):  
Michael J. Walsh ◽  
Richard D. Devlin ◽  
Stephen B. Powles
Keyword(s):  
Prolonged Exposure ◽  
Seedling Emergence ◽  
Soil Surface ◽  
Growing Season ◽  
The Novel ◽  
Herbicide Application ◽  
Application Timing ◽  
Control Practice ◽  
Rigid Ryegrass ◽  
Weed Emergence

The earliest possible seeding of wheat crops in the southern Australian dryland cropping zone is prevented by the lack of a weed control practice that adequately controls initial weed seedling emergence at the start of the growing season. The objective of this study was to determine the potential for using residual herbicides applied up to 1 mo before the start of the growing season to control rigid ryegrass seedlings that emerge after the season-opening rains. In a series of glasshouse studies, S-metolachlor and propyzamide were found to effectively persist on the soil surface through prolonged exposure to hot, dry, and intense sunlight conditions, preventing the establishment of rigid ryegrass seedlings. In addition, these herbicides caused little or no effect on subsequently seeded wheat. It also was determined that S-metolachlor had the potential to retain efficacy on rigid ryegrass seedlings after 12 wk of exposure on the soil surface to these conditions. These studies have identified two herbicides with the potential for use at the novel application timing, i.e., before the commencement of the growing season, in Mediterranean climates of southern Australia.

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