CANOLA SEED SURVIVAL OVER WINTER IN THE FIELD IN ALASKA

1990 ◽  
Vol 70 (3) ◽  
pp. 799-807 ◽  
Author(s):  
S. D. SPARROW ◽  
C. W. KNIGHT ◽  
J. S. CONN
Keyword(s):  
Seed Viability ◽  
Seed Storage ◽  
Soil Surface ◽  
Early Spring ◽  
Late Winter ◽  
Burial Depth ◽  
Canola Seed ◽  
Seed Survival ◽  
Snow Fence ◽  
Better Than

Factors affecting seed survival of spring canola (Brassica campestris L. ’Tobin’), over two winters in the field at Delta Junction, Alaska were studied. In October, seeds were placed in polypropylene mesh envelopes and buried. The packets were exhumed the next spring and seed viability was determined. Factors studied included seed age, seed treatment, protection by snow-fence enclosures, burial depth, and spring retrieval date. During the first winter, survival of seeds near the soil surface until March was 65%, but many died during spring. During the second winter, seed viability in March was much lower than it had been in the previous March, but no significant mortality occurred during spring. Freshly harvested seeds generally survived better than seeds which had been stored for 1 yr. Seeds buried well below the soil surface and seeds placed inside snow-fence enclosures survived better than seeds placed near the soil surface outside enclosures. Results indicate that factors such as seed storage and protection from extreme temperatures and temperature fluctuations during late winter and early spring are important determinants of canola seed survival over winter. These factors could help explain why large populations of volunteer canola arise from seeds which have fallen from mature pods, whereas harvested, stored seeds planted during fall or early spring often produce poor stands in Alaska.Key words: Seed survival, seed mortality, seed germination, seed dormancy, seed overwintering, volunteer canola

Glyphosate Resistance Does Not Affect Palmer Amaranth (Amaranthus palmeri) Seedbank Longevity

Weed Science ◽  
2013 ◽  
Vol 61 (2) ◽  
pp. 283-288 ◽  
Author(s):  
Lynn M. Sosnoskie ◽  
Theodore M. Webster ◽  
A. Stanley Culpepper
Keyword(s):  
Seed Viability ◽  
Glyphosate Resistance ◽  
Early Spring ◽  
Palmer Amaranth ◽  
Food Sources ◽  
Late Winter ◽  
Burial Depth ◽  
Amaranth Seed ◽  
Seed Trap ◽  
Soil Seedbank

A greater understanding of the factors that regulate weed seed return to and persistence in the soil seedbank is needed for the management of difficult-to-control herbicide-resistant weeds. Studies were conducted in Tifton, GA to (1) evaluate whether glyphosate resistance, burial depth, and burial duration affect the longevity of Palmer amaranth seeds and (2) estimate the potential postdispersal herbivory of seeds. Palmer amaranth seeds from glyphosate-resistant and glyphosate-susceptible populations were buried in nylon bags at four depths ranging from 1 to 40 cm for intervals ranging between 0 and 36 mo, after which the bags were exhumed and seeds evaluated for viability. There were no detectable differences in seed viability between glyphosate-resistant and glyphosate-susceptible Palmer amaranth seeds, but there was a significant burial time by burial depth interaction. Palmer amaranth seed viability for each of the burial depths declined over time and was described by exponential decay regression models. Seed viability at the initiation of the study was ≥ 96%; after 6 mo of burial, viability declined to 65 to 78%. As burial depth increased, so did Palmer amaranth seed viability. By 36 mo, seed viability ranged from 9% (1-cm depth) to 22% (40-cm depth). To evaluate potential herbivory, seed traps with three levels of exclusion were constructed: (1) no exclusion, (2) rodent exclusion, and (3) rodent and large arthropod exclusion. Each seed trap contained 100 Palmer amaranth seeds and were deployed for 7 d at irregular intervals throughout the year, totaling 27 sample times. There were seasonal differences in seed recovery and differences among type of seed trap exclusion, but no interactions. Seed recovery was lower in the summer and early autumn and higher in the late winter and early spring, which may reflect the seasonal fluctuations in herbivore populations or the availability of other food sources. Seed recovery was greatest (44%) from the most restrictive traps, which only allowed access by small arthropods, such as fire ants. Traps that excluded rodents, but allowed access by small and large arthropods, had 34% seed recovery. In the nonexclusion traps, only 25% of seed were recovered, with evidence of rodent activity around these traps. Despite the physically small seed size, Palmer amaranth is targeted for removal from seed traps by seed herbivores, which could signify a reduction in the overall seed density. To be successful, Palmer amaranth management programs will need to reduce soil seedbank population densities. Future studies need to address factors that enhance the depletion of the soil seedbank and evaluate how these interact with other weed control practices.

Seasonal activity and estivation of lumbricid earthworms in the midlands of Tasmania

Soil Research ◽  
1994 ◽  
Vol 32 (6) ◽  
pp. 1355 ◽  
Author(s):  
RB Garnsey
Keyword(s):  
Soil Moisture ◽  
Adult Development ◽  
Survival Rates ◽  
Soil Surface ◽  
Early Spring ◽  
Lumbricus Rubellus ◽  
Late Winter ◽  
Cocoon Production ◽  
Density And Biomass ◽  
Earthworm Activity

Earthworms have the ability to alleviate many soil degradational problems in Australia. An attempt to optimize this resource requires fundamental understanding of earthworm ecology. This study reports the seasonal changes in earthworm populations in the Midlands of Tasmania (<600 mm rainfall p.a.), and examines, for the first time in Australia, the behaviour and survival rates of aestivating earthworms. Earthworms were sampled from 14 permanent pastures in the Midlands from May 1992 to February 1994. Earthworm activity was significantly correlated with soil moisture; maximum earthworm activity in the surface soil was evident during the wetter months of winter and early spring, followed by aestivation in the surface and subsoils during the drier summer months. The two most abundant earthworm species found in the Midlands were Aporrectodea caliginosa (maximum of 174.8 m-2 or 55.06 g m-2) and A. trapezoides (86 m-2 or 52.03 g m-2), with low numbers of Octolasion cyaneum, Lumbricus rubellus and A. rosea. The phenology of A. caliginosa relating to rainfall contrasted with that of A. trapezoides in this study. A caliginosa was particularly dependent upon rainfall in the Midlands: population density, cocoon production and adult development of A. caliginosa were reduced as rainfall reduced from 600 to 425 mm p.a. In contrast, the density and biomass of A. trapezoides were unaffected by rainfall over the same range: cocoon production and adult development continued regardless of rainfall. The depth of earthworm aestivation during the summers of 1992-94 was similar in each year. Most individuals were in aestivation at a depth of 150-200 mm, regardless of species, soil moisture or texture. Smaller aestivating individuals were located nearer the soil surface, as was shown by an increase in mean mass of aestivating individuals with depth. There was a high mortality associated with summer aestivation of up to 60% for juvenile, and 63% for adult earthworms in 1993 in the Midlands. Cocoons did not survive during the summers of 1992 or 1994, but were recovered in 1993, possibly due to the influence of rainfall during late winter and early spring.

scholarly journals Abundance and diversity of soil arthropods and fungi in shelterbelts integrated with pastures in the central tablelands of New South Wales, Australia

2012 ◽  
Vol 58 (No. 12) ◽  
pp. 560-568 ◽  
Author(s):  
E.W. Mbuthia ◽  
J.H. Shariff ◽  
A. Raman ◽  
D.S. Hodgkins ◽  
H.I. Nicol ◽  
...  
Keyword(s):  
Organic Matter ◽  
Biological Diversity ◽  
Soil Depth ◽  
Soil Surface ◽  
Early Spring ◽  
Late Winter ◽  
Soil Arthropods ◽  
South Wales ◽  
Abundance And Diversity ◽  
The Relationship

Shelterbelts are important for the sustainability of agriculture because they provide a variety of benefits to farmers and the society. Several published papers demonstrate that integration of shelterbelts with agroecosystems offers positive outcomes, such as better yield, more congenial microclimate, and greater organic matter levels. Nonetheless, soil biological diversity, the driver of greater organic matter levels, has not been convincingly tested and verified yet. In addressing this gap, we measured abundance and diversity of populations of arthropods and fungi in three<br />11-year old shelterbelts integrated with pasture to determine whether a correlation exists between the abundance of and diversity in populations of arthropods and fungi in two seasons: late autumn-early winter (May&ndash;June 2011) and late winter-early spring (August&ndash;September 2011). Litter from the soil surface and soil from two depths were sampled at increasing distance from the midpoint of shelterbelts for the extraction of arthropods and isolation culturing of fungi. The relationship among distance, depth and biodiversity of different groups of arthropods and fungi was analysed using linear regression. We found that over both seasons arthropod abundance in the litter and soil declined with increasing distance from the midpoint of the shelterbelts, and with soil depth. However, fungi abundance in either season was not affected by proximity to the shelterbelt but increased with greater soil depth. Distance from the shelterbelt midpoints did not bear an impact on the diversity richness of both arthropods and fungi.

The dynamics of Trifolium repens in a permanent pasture I. The population dynamics of leaves and nodes per shoot axis

1989 ◽  
Vol 237 (1287) ◽  
pp. 133-173 ◽  
Keyword(s):  
Spatial Variation ◽  
Trifolium Repens ◽  
Death Rate ◽  
Birth Rate ◽  
Soil Surface ◽  
Early Spring ◽  
Late Winter ◽  
Seasonal Fluctuations ◽  
Permanent Pasture ◽  
One Year

The framework is developed for a formal quantitative analysis of the vegetative dynamics of Trifolium repens , based on partitioning the components of its growth. The method is used to describe the vegetative dynamics of T. repens in one pasture during the course of one year. Seasonal and spatial variation were analysed by regression on several environmental variables. The present paper includes only a partial analysis, covering the dynamics of leaves and nodes per shoot axis. The remainder of the analysis will be presented in subsequent papers. The production of modules per shoot axis, and the subsequent mortality of leaves, and burial and mortality of nodes, showed different patterns of spatial and seasonal variability, and different types of response to the environment. There was much seasonal and little spatial variation in rates of birth, burial and death of leaves and nodes. In contrast, there was relatively little seasonal and much spatial variation in the numbers of leaves and nodes, even though these numbers are determined by present and past births and deaths. The rate of production of leaves by individual apices varied from 0.01 per day to 0.19 per day. It appeared to be determined largely by temperature, probably of the apex, but also to some extent by genotype. Leaves survived for 1-21 weeks. The risk of leaf mortality varied with the age of the leaf, the number of sheep in the field, and the season. Leaves born in November tended to live longest, and those born in summer with many sheep shortest. At least 56% of leaves were utilized by sheep, the remainder dying from other causes. Seasonal fluctuations in death rate of leaves tended to lag three weeks behind fluctuations in birth rate, but with additional fluctuations caused by changes in grazing. The lag caused there to be a minimum of 1-5 leaves per axis in January, and a maximum of 3-12 in August, although at all times the number of leaves was increasing on some axes and decreasing on others. Axes were progressively buried by worm casts and leaf litter within 0-39 weeks of birth. The rate of burial appeared to be determined largely by earthworm activity and by treading by sheep. In autumn and early spring, nodes and internodes were buried faster than new ones were born. As a result, as few as three internodes were exposed on average in March, compared with a maximum mean of 20 in August. By late winter, some axes were entirely buried and started to grow vertically upwards towards the soil surface. Nodes survived for 14-85 weeks, the mean longevity being 51 weeks. On average, each axis bore 25 nodes, with a range of 10-49 nodes. Seasonal fluctuations in death rate lagged some 4-8 weeks behind those in birth rate. Survivial of nodes and internodes was dependent on the establishment and survival of roots. When the oldest rooted node on an axis died, all of the axis between it and the next rooted node also died. The development of pseudo-taproots increased the longevity of nodes by 100 days. Leaves had much shorter lives than their nodes. The ‘average’ shoot axis bore 3.5 nodes with leaves, 4.2 nodes still visible but without leaves, and 17.6 nodes buried beneath worm casts and litter.

scholarly journals Monilinia vaccinii-corymbosi Apothecial Development Associated With Mulch Depth and Timing of Application

Plant Disease ◽  
2017 ◽  
Vol 101 (5) ◽  
pp. 807-814
Author(s):  
Jade Florence ◽  
Jay Pscheidt
Keyword(s):  
Soil Surface ◽  
Vaccinium Corymbosum ◽  
Early Spring ◽  
Douglas Fir ◽  
Late Winter ◽  
Bare Ground ◽  
Application Timing ◽  
Ground Treatment ◽  
Treatment Application ◽  
Blueberry Leaves

Pseudosclerotia of Monilinia vaccinii-corymbosi overwinter on the soil surface and develop apothecia in early spring, supplying primary inoculum for mummy berry disease of blueberry. Burial of pseudosclerotia in soil and incubation in the dark have previously been identified as critical factors inhibiting M. vaccinii-corymbosi apothecial development. Mulches of Douglas-fir (Pseudotsuga menziesii) sawdust at 2.5 or 5 cm depths, blueberry leaves (Vaccinium corymbosum cv. Bluetta) at a 2.5 cm depth, and a bare ground (no mulch) control were assessed for an effect on apothecial development in the spring for 2 years. Mulches were applied corresponding to pseudosclerotial overwintering stages. Loss of mulch depth was also assessed throughout the overwintering season. A 5 cm depth of Douglas-fir sawdust was associated with greater apothecial suppression in comparison with bare ground. Douglas-fir sawdust at a 2.5 cm depth varied in effectiveness, while 2.5 cm of blueberry leaves was not more effective at suppressing apothecial development than the bare ground treatment. Application timing did not affect apothecial development, but mulches lost significantly more depth when applied at the beginning of the overwintering season as compared with late winter mulches. Therefore, loss of mulch thickness due to weathering and/or decomposition may also affect apothecial development.

Observations on tillering in cultivars of phalaris under rotational grazing in a year with a summer - autumn drought

1997 ◽  
Vol 48 (4) ◽  
pp. 467 ◽  
Author(s):  
R. A. Culvenor
Keyword(s):  
Stem Elongation ◽  
Reproductive Development ◽  
Moisture Stress ◽  
Grazing Pressure ◽  
Early Spring ◽  
Late Winter ◽  
Grazing Tolerance ◽  
Summer Dormancy ◽  
Stem Development ◽  
Better Than

Changes in tiller numbers, timing of stem elongation, and tiller survival under summer moisture stress were measured in phalaris (Phalaris aquatica L.) pastures rotationally grazed at 15 wethers/ha during a study of the survival and productivity of a semi-winter-dormant cultivar (Australian) compared with 3 winter-active cultivars (Sirosa, Holdfast, Perla Retainer). The semi-winter-dormant cultivar maintained higher tiller numbers per plant and per area than the 3 winter-active cultivars, was later in its reproductive stem development, and was capable of more new tillering early in spring, but could display higher rates of tiller death late in spring. Although stem elongation in Australian started later in 1990, it was no less synchronous than in the winter-active cultivars. However, Sirosa had a higher proportion of elongating tillers than Australian under very infrequent grazing in a supplementary experiment during 1991. Cultivars did not differ in the proportion of tillers that were decapitated during spring 1990. Perla Retainer displayed higher summer dormancy after rainfall in January 1991 and new tillers of Perla Retainer and Holdfast survived subsequent drought better than tillers of Australian. However, regeneration of the tiller population of Australian after drought ended was enhanced by a slightly higher propensity for tillering during July–September 1991. The results suggested that maintaining grazing pressure and frequency in late winter and early spring should enhance tiller survival and improve the resilience of phalaris to episodes of heavy spring grazing. Later reproductive development probably benefits grazing tolerance in semi-winter-dormant cultivars, but the value of selecting for this in winter-active phalaris is uncertain. In areas with harsh summers, higher summer dormancy is required for survival combined with a capacity for tiller survival should growth occur. However, unnecessarily high summer dormancy will reduce the growth of green herbage and, consequently, animal production.

Non-deep complex morphophysiological dormancy inNarcissus longispathus(Amaryllidaceae): implications for evolution of dormancy levels within sectionPseudonarcissi

2013 ◽  
Vol 23 (2) ◽  
pp. 141-155 ◽  
Author(s):  
José M. Herranz ◽  
Elena Copete ◽  
Pablo Ferrandis
Keyword(s):  
Seed Storage ◽  
Early Spring ◽  
Late Winter ◽  
Natural Conditions ◽  
Storage Duration ◽  
Morphophysiological Dormancy ◽  
Light Requirements ◽  
Radicle Emergence ◽  
Almost All ◽  
Embryo Length

AbstractNarcissus longispathus(Amaryllidaceae) is a perennial geophyte and a Mediterranean narrowly endemic species. At dispersal time,N. longispathusseeds are dormant and have underdeveloped embryos. This work aimed to determine requirements for dormancy break and germination and to compare dormancy traits with those of the two endemic Iberian congeners. Phenology of embryo growth and germination were studied by regularly exhuming seeds sown in near-natural conditions. Temperature and light requirements for embryo growth, breaking of dormancy and germination were determined by incubating seeds under controlled laboratory conditions. Mean embryo length in fresh seeds was 1.50 mm, and embryos had to grow to 3.80 mm before radicle emergence. Embryos grew to full size and seeds germinated when they were warm stratified for 2 months (optimum 1 month at 20/7°C+1 month at 15/4°C), then cold stratified at 5°C for 2 months, and finally incubated at cool temperatures (15/4°C) for 30 d. However, in seeds only subjected to either warm or cold stratification, the embryos hardly grew and did not germinate. In natural conditions, the embryos elongate in autumn–winter, and in late winter–early spring (March) almost all radicles and seedlings emerged. Velocity of embryo growth and germination percentages increased with seed storage duration. Seeds ofN. longispathushave non-deep complex morphophysiological dormancy (MPD). This is the first report of such a level of MPD inNarcissus. Our data suggest that non-deep complex MPD may have been derived from intermediate complex MPD in the sectionPseudonarcissi.

scholarly journals Seedbank Persistence of Palmer Amaranth (Amaranthus palmeri) and Waterhemp (Amaranthus tuberculatus) across Diverse Geographical Regions in the United States

Weed Science ◽  
2018 ◽  
Vol 66 (4) ◽  
pp. 446-456 ◽  
Author(s):  
Nicholas E. Korres ◽  
Jason K. Norsworthy ◽  
Bryan G. Young ◽  
Daniel B. Reynolds ◽  
William G. Johnson ◽  
...  
Keyword(s):  
United States ◽  
Seed Viability ◽  
Soil Surface ◽  
The United States ◽  
Palmer Amaranth ◽  
Soil Conditions ◽  
Burial Depth ◽  
Amaranthus Palmeri ◽  
Seed Damage ◽  
Amaranthus Tuberculatus

AbstractKnowledge of the effects of burial depth and burial duration on seed viability and, consequently, seedbank persistence of Palmer amaranth (Amaranthus palmeriS. Watson) and waterhemp [Amaranthus tuberculatus(Moq.) J. D. Sauer] ecotypes can be used for the development of efficient weed management programs. This is of particular interest, given the great fecundity of both species and, consequently, their high seedbank replenishment potential. Seeds of both species collected from five different locations across the United States were investigated in seven states (sites) with different soil and climatic conditions. Seeds were placed at two depths (0 and 15 cm) for 3 yr. Each year, seeds were retrieved, and seed damage (shrunken, malformed, or broken) plus losses (deteriorated and futile germination) and viability were evaluated. Greater seed damage plus loss averaged across seed origin, burial depth, and year was recorded for lots tested at Illinois (51.3% and 51.8%) followed by Tennessee (40.5% and 45.1%) and Missouri (39.2% and 42%) forA. palmeriandA. tuberculatus, respectively. The site differences for seed persistence were probably due to higher volumetric water content at these sites. Rates of seed demise were directly proportional to burial depth (α=0.001), whereas the percentage of viable seeds recovered after 36 mo on the soil surface ranged from 4.1% to 4.3% compared with 5% to 5.3% at the 15-cm depth forA. palmeriandA. tuberculatus, respectively. Seed viability loss was greater in the seeds placed on the soil surface compared with the buried seeds. The greatest influences on seed viability were burial conditions and time and site-specific soil conditions, more so than geographical location. Thus, management of these weed species should focus on reducing seed shattering, enhancing seed removal from the soil surface, or adjusting tillage systems.

scholarly journals Seed Germination of Sunflower as a Case Study for the Risk Assessment and Management of Transgenic Plants Used for Environmental Remediation in South Korea

2020 ◽  
Vol 12 (23) ◽  
pp. 10110
Author(s):  
Kyong-Hee Nam ◽  
Sung Min Han
Keyword(s):  
Transgenic Plants ◽  
South Korea ◽  
Environmental Remediation ◽  
Safety Management ◽  
Seed Viability ◽  
Soil Surface ◽  
Burial Depth ◽  
Unintended Effects ◽  
Natural Ecosystems ◽  
Experimental Conditions

In South Korea, the safety management of living modified organisms (LMOs) is regulated by seven government agencies depending on their use, and the Ministry of Environment is in charge of LMOs to manage environmental remediation and effects on natural ecosystems. This study aimed to develop appropriate research tools to determine the factors affecting the invasiveness of transgenic plants used for environmental remediation. We examined the persistence of sunflower (Helianthus annuus L.) as a candidate by comparing the seed viability at different controlled temperatures and soil depths (ranging from 0 to 30 cm). The germination characteristics of seeds significantly differed between cultivars and temperatures. The field trials indicated that seeds buried at a depth of 30 cm mostly decayed within three weeks, whereas those buried at 0 cm persisted for eight weeks but decayed after sixteen weeks, implying a significant interaction between burial depth and seed persistence. At all soil depths, no dormant seeds were detected over one week after burial. These results suggest that sunflower seeds could not be successfully established under our experimental conditions. Since seeds on the soil surface demonstrated the highest rates of germination, such seeds may require particularly careful management to prevent unintended effects on ecosystems.

Postemergence Control of Wild Garlic (Allium vineale) in Turfgrass

1992 ◽  
Vol 6 (1) ◽  
pp. 144-148 ◽  
Author(s):  
Gregory P. Ferguson ◽  
G. Euel Coats ◽  
Galen B. Wilson ◽  
David R. Shaw
Keyword(s):  
Early Spring ◽  
Final Evaluation ◽  
Late Winter ◽  
Late Fall ◽  
Common Bermudagrass ◽  
Control Equivalent ◽  
Wild Garlic ◽  
Better Than

Experiments were conducted to evaluate imazaquin and selected herbicides for POST control of wild garlic. At the same dosages, imazaquin applied in late November/early December (late fall) controlled wild garlic better than when applied in early March (late winter) when assessed in May. Imazaquin provided control equivalent to 1120 g ae ha–12,4-D plus imazaquin. Imazapyr, imazamethabenz, or imazethapyr at 280, 1120, or 560 g ai ha–1, respectively, provided control equivalent to 560 g ai ha–1imazaquin. Thifensulfuron at 70 g ai ha–1provided better control applied in late winter (85%) than late fall (45%). All herbicides consistently provided better control than 2,4-D plus mecoprop plus dicamba, except thifensulfuron applied in late fall, at the final evaluation. Common bermudagrass growth in early spring was delayed 2 mo by ≥ 560 g ha–1imazaquin, 70 g ha–1thifensulfuron, imazethapyr, and imazapyr or 2,4-D plus mecoprop plus dicamba applied in late winter. Imazamethabenz did not delay common bermudagrass growth. Late fall applications of 1120 g ha–1imazaquin did not delay growth while ≥ 560 g ha–1imazethapyr delayed common bermudagrass growth through April.

Sign in / Sign up

Export Citation Format

Share Document