Emergence and survival of Populus tremula seedlings under varying moisture conditions

2003 ◽  
Vol 33 (11) ◽  
pp. 2081-2088 ◽  
Author(s):  
Tarja Latva-Karjanmaa ◽  
Leena Suvanto ◽  
Kari Leinonen ◽  
Hannu Rita
Keyword(s):  
Seedling Emergence ◽  
Populus Tremula ◽  
Sowing Time ◽  
Large Numbers ◽  
Seedling Emergence And Survival ◽  
Negative Effect ◽  
Sowing Experiment ◽  
Moisture Conditions ◽  
Root Suckers ◽  
Survival Of Seedlings

Aspen produces large numbers of seeds, even though it mainly reproduces asexually with root suckers. The aim of this study was to find out how different moisture conditions affect emergence and survival of Populus tremula L. seedlings. This was studied with a sowing experiment (totally randomized factorial design). There were altogether 10 blocks, each containing 16 microsites and three treatments (sowing time, watering, sowing shelter) replicated twice in each block. Seedlings emerged on 56% of microsites. Sowing time affected seedling emergence. Both the proportion of microsites with seedlings and the number of seedlings per microsite were lower after first than after second sowing, when the weather was rainier. Watering increased the number of seedlings per microsite, but the proportion of micro sites with at least one seedling was not affected. Sowing shelter had a negative effect on the seedling emergence, especially after second sowing. The survival of seedlings was low (10%) and strongly dependent on watering. The effect of block and its interactions with treatments indicated that seedling emergence and survival depended also on seedbed conditions. We conclude that sexual reproduction of aspen may occur in nature, but it is rare. The seeds also maintained their germinability longer than earlier observed.

Survival and fecundity of wild radish (Raphanus raphanistrum L.) plants in relation to cropping, time of emergence and chemical control

1988 ◽  
Vol 39 (3) ◽  
pp. 385 ◽  
Author(s):  
FD Panetta ◽  
DJ Gilbey ◽  
MF D'Antuono
Keyword(s):  
Chemical Control ◽  
Seedling Emergence ◽  
Sowing Date ◽  
Wild Radish ◽  
Raphanus Raphanistrum ◽  
Large Numbers ◽  
Negative Effect ◽  
Grain Contamination ◽  
Survival Of Seedlings

During consecutive seasons, wild radish (Raphanus raphanistrum L.) seedling emergence decreased exponentially with increasing time after the emergence of lupin crops. Initial survival of seedlings was markedly reduced by pre-emergence applications of simazine at 0.75 kg a.i. ha-1. In the absence of herbicide, however, the presence of a lupin crop did not have a negative effect upon early survival. Probabilities of reproduction of wild radish plants decreased with later emergence within treatments; no plants which emerged later than 21 days after crop emergence produced seeds. Seed production by wild radish was considerably higher when lupins were sown late. Regardless of sowing date, the application of triazine herbicides reduced the amount of seeds produced to the point where grain contamination was insignificant. However, the few plants which escaped herbicide treatment produced large numbers of seeds. Virtually no seeds were produced when additional post-emergence applications of simazine (0.375 kg a.i. ha-1) were made. It is argued that the major role of post-emergence application in this crop-weed system is to prevent reproduction by plants which escape the pre-emergence application, rather than to control late-emerging plants.

scholarly journals Suppression by three grass species of broom seedling emergence and survival

2018 ◽  
Vol 71 ◽  
pp. 57-65 ◽  
Author(s):  
Hop Tran ◽  
Kerry C. Harrington ◽  
Hossein Ghanizadeh ◽  
Alastair W. Robertson ◽  
Michael S. Watt
Keyword(s):  
Weed Management ◽  
Lolium Multiflorum ◽  
Seedling Emergence ◽  
Ground Cover ◽  
Italian Ryegrass ◽  
Grass Species ◽  
Holcus Lanatus ◽  
Planted Forests ◽  
Large Numbers ◽  
Survival Of Seedlings

Grass ground covers are often used in forestry to suppress weed germination, but little is known on how best to use grasses to suppress broom (Cytisus scoparius). In this field study, three grass species, Yorkshire fog (Holcus lanatus), Italian ryegrass (Lolium multiflorum) and perennial ryegrass (Lolium perenne), were sown at three rates in autumn and spring, then suppression of broom germination and survival of seedlings was measured. Scarified broom seeds sown at the same time as the grasses produced large numbers of competitive plants by the final assessment 12 months after sowing, regardless of the time of sowing, species of grass sown or rate of grass sown. However, no seedling emergence was recorded for the treatments in which broom seeds were sown 6 months after the grass ground cover had established. All three grass species established well, although only Yorkshire fog performed well in both seasons. Grass ground covers showed some potential to be used as part of weed management for broom in planted forests, but probably only if herbicides can also be used to control broom establishing at the same time as the grass.

Soil mulches and sprayed coatings and seed washing to aid Chenopod establishment on saline soil.

1985 ◽  
Vol 7 (1) ◽  
pp. 22 ◽  
Author(s):  
CV Malcolm ◽  
CV Malcolm ◽  
TC Swaan ◽  
TC Swaan
Keyword(s):  
Low Temperatures ◽  
Field Experiments ◽  
Saline Soil ◽  
Seedling Emergence ◽  
Germination Inhibitors ◽  
Seedling Emergence And Survival ◽  
High Dilutions ◽  
Sprayed Coatings ◽  
Better Than ◽  
Survival Of Seedlings

Three field experiments were conducted on saline sites to compare vermiculite and 'Compeat' mulches and sprayed latex or bituminous coatings as coverings for seed placed on soil in a 'V' shaped niche. Chenopod fruits were washed in water to remove germination inhibitors before planting. The effectiveness of the treatments were assessed by counting seedling emergence and survival. Black pigmented latex and bituminous emulsion coatings gave significant improvements in emergence and survival on Atriplex spp. and Maireana brevifolia seedlings over 10 months. Bituminous emulsion stabilized the soil in the niche better than lattices, especially at high dilutions. Seed washing doubled emergence of Atriplex amnicola (river saltbush) if used in combination with a mulch. Vermiculite gave a marked increase in emergence and survival of seedlings of river saltbush and was significantly better than 'Compeat'. Low temperatures and high soil salinities were postulated as possible causes of reduced emergence on saline sites.

Seedling emergence of Pinus sylvestris in characterized seedbed substrates under different moisture conditions

2000 ◽  
Vol 30 (11) ◽  
pp. 1766-1777 ◽  
Author(s):  
Gunilla Oleskog ◽  
Harald Grip ◽  
Urban Bergsten ◽  
Kenneth Sahlén
Keyword(s):  
Organic Matter ◽  
Pinus Sylvestris ◽  
Seedling Emergence ◽  
Air Humidity ◽  
Soil Water Tension ◽  
Relative Air Humidity ◽  
Negative Effect ◽  
Organic Admixture ◽  
Moisture Conditions ◽  
Water Tension

Establishment of Scots pine (Pinus sylvestris L.) stands from seed is often unsuccessful because of unsuitable environmental conditions, such as limited soil moisture or air humidity. Improved seedling emergence could be achieved by soil preparation if site-specific optimal seedbeds were specified. Therefore the effects of seedbed substrates (13 characterized mixtures of sand, silt, and organic matter) on seedling emergence were determined after 14-day emergence tests in small laboratory chambers with four moisture conditions (2 levels of relative air humidity (RH), 95 and 65%, in combination with 2 levels of substrate water tension, 3 and 10 kPa). Seeds were placed in (partially buried) and on noncompacted and compacted substrates. At 95% RH, seedling emergence was 80 to 95% (seed lot maximum 94%) regardless of the substrate, with the exception of seeds placed in silt substrates (30-70%). At 65% RH, seedling emergence was 90% on silt, but considerably lower on organic matter and sand substrates, where organic admixture improved emergence for sand, but had a neutral or negative effect for silt. At 65% RH, partial seed burial, i.e., with good seed-substrate contact, improved emergence for organic matter and sand substrates, but impaired emergence for pure silt in noncompacted substrates at 3 kPa soil water tension. The effect of compaction on emergence was small for most substrates and had an effect only at 65% RH and 10 kPa tension. Seedling emergence and soil hydraulic conductivity at 3 kPa water tension and 95% RH were negatively correlated for partially buried seeds, but regardless of seed position, they were positively correlated at 10 kPa tension and 65% RH. These results can be used as guiding principles for the creation of seedbed substrates and seeding techniques.

Bigleaf maple seedling establishment and early growth in Douglas-fir forests

1988 ◽  
Vol 18 (10) ◽  
pp. 1226-1233 ◽  
Author(s):  
Jeremy S. Fried ◽  
John C. Tappeiner II ◽  
David E. Hibbs
Keyword(s):  
Seed Predation ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Early Growth ◽  
Douglas Fir ◽  
Stand Development ◽  
Size Distributions ◽  
Canopy Density ◽  
Successful Establishment ◽  
Survival Of Seedlings

Survival, age and height distributions, and stocking of bigleaf maple (Acermacrophyllum Pursh) seedlings were studied in 1- to 250-year-old Douglas-fir (Pseudotsugamenziesii (Mirb.) Franco) stands in western Oregon to identify the stages in stand development in which bigleaf maple is most likely to establish successfully from seed. Maple seedling emergence averaged 30–40% where seeds were planted and protected from rodents but was typically <2% for unprotected seeds. Seedling survival after 2 years was highly dependent on canopy density, measured by percent sky. Average 1st-year survival of seedlings originating from planted, protected seeds was highest in clearcuts (1–2 years old, 36% survival, 56% sky) and pole-size stands (41–80 years old, 30% survival, 17% sky) with sparse understories and canopies. It was lowest in young stands with dense canopies (20–40 years old, 4% survival, 8% sky) and old stands (81–250 years old, 14% survival, 13% sky) with dense understories. Naturally regenerated populations of bigleaf maple seedlings, which occurred in aggregations (0.005–0.04 ha in area), were most abundant (up to 10 000/ha) in pole-size Douglas-fir stands. Although seedling size distributions within stands had a strongly inverse J shaped form, size distributions within aggregations appeared more normal (bell-shaped). Seedling age rarely exceeded 15 years. Seedlings grew slowly in the understory, often reaching only 25 cm in height after 8–10 years, and were intensively browsed by deer. Naturally regenerated seedlings were virtually absent from clearcuts, probably because of dense competing vegetation and lack of seed caused by poor dispersal and seed predation. The "window" for the most successful establishment of bigleaf maple seedlings appears to begin after canopy thinning and end before forbs and shrubs invade.

Weed Seedling Emergence and Survival as Affected by Crop Canopy

2008 ◽  
Vol 22 (4) ◽  
pp. 736-740 ◽  
Author(s):  
Randy L. Anderson
Keyword(s):  
Winter Wheat ◽  
Seed Production ◽  
Spring Wheat ◽  
Seedling Emergence ◽  
Crop Canopy ◽  
Cool Season ◽  
Common Lambsquarters ◽  
Green Foxtail ◽  
Seedling Emergence And Survival ◽  
Weed Dynamics

This study measured impact of cool-season crops on seedling emergence, survival, and seed production of weeds common in corn and soybean. Weed dynamics were monitored in permanently marked quadrats in winter wheat, spring wheat, and canola. Three species, green foxtail, yellow foxtail, and common lambsquarters, comprised more than 80% of the weeds observed in the study. Seedling emergence was reduced by winter wheat, but not by spring wheat or canola, when compared with adjacent quadrats without a crop canopy. Approximately 10% of seedlings in spring wheat and canola developed into seed-bearing plants, but no seed-bearing plants were present in winter wheat at harvest. Common lambsquarters produced more than 1,100 seeds/plant, whereas a foxtail plant produced 85 seeds, averaged across spring wheat and canola. At harvest, new seedlings were present in all crops; thus, control after harvest will be required to prevent seed production in the fall. Winter wheat may provide an opportunity to disrupt population dynamics of weeds common in corn and soybean without requiring herbicides.

Direct seeding of PinusSylvestris using microsite preparation and invigorated seed lots of different quality: 2-year results

1994 ◽  
Vol 24 (1) ◽  
pp. 77-86 ◽  
Author(s):  
Hans Winsa ◽  
Urban Bergsten
Keyword(s):  
Seed Quality ◽  
Seedling Survival ◽  
Seedling Emergence ◽  
Mineral Soil ◽  
Direct Seeding ◽  
Growing Seasons ◽  
Humus Layer ◽  
Negative Effect ◽  
Mean Germination Time ◽  
Better Than

Direct seeding of Pinussylvestris L. is a regeneration method, with potential for development considering scarification, microsite preparation, seed invigoration, and seed quality. Three seed lots of different quality concerning seed weight, germination percent, and mean germination time were used on two sites in northern Sweden. Microsite preparation, 2 cm deep pyramidal indentations, of the mineral soil improved seedling emergence on the two sites by 48 and 62%, respectively, compared with seeding without preparation other than removal of the humus layer. Microsite preparation in combination with invigorated seed, i.e., seed incubated at 30% moisture content for 7 days at 15 °C, resulted in seedling emergence of about 85% for the highest and about 50% for the lowest seed quality at both sites. Noninvigorated seed, seeded without microsite preparation, reached about 55% for the highest and 22% at one and 43% at the other for the lowest seed quality. Without microsite preparation there was no, or a negative, effect of seed invigoration on seedling emergence. Seedling survival after the first winter improved significantly with better seed quality. Survival averaged 92 and 72% at the two sites, with frost heaving causing most mortality. Seedlings from invigorated and redried seed survived better than seedlings from untreated seed. Seedlings from the best seed quality had higher values in seedling height, about 35%, shoot length, about 60%, and needle length, about 30%, after two growing seasons than seedlings from lower seed qualities. Invigoration and microsite preparation had no effect on measured growth characteristics.

scholarly journals Effects of enhanced hydrological connectivity on Mediterranean salt marsh fish assemblages with emphasis on the endangered Spanish toothcarp (Aphanius iberus)

2016 ◽  
Author(s):  
Patricia Prado ◽  
Carles Alcaraz ◽  
Lluis Jornet ◽  
Nuno Alberto Caiola ◽  
Carles Ibáñez
Keyword(s):  
Salt Marsh ◽  
Fish Community ◽  
Fish Assemblages ◽  
Fish Population ◽  
Important Variable ◽  
Hydrological Connectivity ◽  
Local Diversity ◽  
Large Numbers ◽  
Negative Effect ◽  
Migratory Movements

The hydrological connectivity between the salt marsh and the sea was partially restored in a Mediterranean wetland containing isolated ponds resulting from former salt extraction and aquaculture activities. A preliminary assessment provided evidence that ponds farther from the sea hosted very large numbers of the endangered Spanish toothcarp, Aphanius iberus, suggesting that individuals had been trapped and consequently reach unnaturally high densities. In order to achieve both habitat rehabilitation and toothcarp conservation, efforts were made to create a gradient of hydrologically connected areas, including isolated fish reservoirs, semi-isolated, and connected salt marsh–sea areas that could allow migratory movements of fish and provide some protection for A. iberus. The fish community was monitored prior to, and for three years after rehabilitation. Results showed an increase in the number of fish species within semi-isolated areas (Zone A), relative to connected areas (Zone B), while at the assemblage level, structural differences between zones were higher than interannual variability. GLMs evidenced that distance to the sea was the most important variable explaining the local diversity of the fish community after restoration, with occasional influence of other factors such as temperature, and depth. The abundance of A. iberus was consistently higher in semi-isolated areas at greater distances from the sea, but a decline occurred in both zones and in isolated reservoir ponds after restoration efforts, which may be attributable to dispersal to adjacent habitats, and to interannual differences in recruitment success. A negative effect of restoration works on fish population cannot be excluded, but the final outcome of the intervention likely needs a longer period .

Native bacteria and cyanobacteria consortia improve seedling emergence and establishment in dryland restoration

2021 ◽  
Author(s):  
Frederick Dadzie ◽  
Angela Moles ◽  
Todd Erickson ◽  
Miriam Munoz-Rojas
Keyword(s):  
Soil Bacteria ◽  
Donor Site ◽  
Seedling Emergence ◽  
Soil Microbial Communities ◽  
Degraded Land ◽  
North West ◽  
Soil Microbial ◽  
Rehabilitation Programs ◽  
Significant Difference ◽  
Seedling Emergence And Survival

&lt;p&gt;Seed-based ecosystem restoration has huge potential to restore degraded lands but currently less than 10 % of directly sown seeds successfully establish in drylands. Soil microbial communities are important for improving plant establishment in degraded land. However, current methods such as soil translocation can potentially disturb the donor site. In this study, we investigated a novel non-destructive method for improving seedling growth of native plants used in restoration through seed-soil-microbial pelleting. We assessed seedling emergence and survival of &lt;em&gt;Triodia epactia&lt;/em&gt; and &lt;em&gt;Acacia inaequilatera&lt;/em&gt; seeds inoculated with whole soil bacteria and cyanobacteria consortia retrieved and isolated from a pristine ecosystem. A field experiment was set-up in a 35m x 40m purpose-built rain exclusion shelter that contained reconstructed soil profiles typically encountered in mine rehabilitation programs of Australia&amp;#8217;s arid north-west. We hypothesized that inoculated seed-soil pellets would improve seedling emergence and survival of these species. After three weeks of planting, seedling emergence in microbially inoculated &lt;em&gt;Acacia&lt;/em&gt; &lt;em&gt;inaequilatera&lt;/em&gt; and &lt;em&gt;Triodia epactia&lt;/em&gt; were 48% and 55% higher than non-inoculated seeds in bacteria and cyanobacteria, respectively. We also tested whether the use of cyanobacteria consortia as inocula promoted higher seedling emergence over whole soil bacteria. We found that there was no significant difference in seedling emergence between the microbial taxa. We show that, improving the diversity of soil microorganisms improves seedling emergence and the seed-soil pellet method used is viable to improve seed-based restoration outcomes.&lt;/p&gt;&lt;p&gt;&lt;strong&gt;Key words&lt;/strong&gt;: Seed-based restoration, microbial community, cyanobacteria, bacteria community, seedling emergence.&lt;/p&gt;

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