The Relation between Stand Density and the Structure of Spring Rape ( Brassica Napus L.)

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The aims of this study were to evaluate seed shedding in spring turnip rape (Brassica rapa L.) and spring rape (B. napus L.) and to assess the effect of delayed harvesting on seed yield loss. Experiments on spring turnip rape (cv. Emma) were conducted in 1988-1990 and on spring rape (cv. Topas) in 1989-1990 in Jokioinen (60o49'N, 23o28'E). Rimmed tin boxes were used to collect seed from shattered pods. They were placed between the continuous rows before pods started to shatter. The shed seeds were collected two to three times a week. Susceptibility and timing of pod shattering varies between spring turnip rape and rape. However, before optimal harvest date spring rape does not shatter significantly more than spring turnip rape. Spring rape starts to shatter more compared with spring turnip rape after its optimal harvest date. It is also more sensitive to weather conditions than spring turnip rape. Furthermore, pod shattering after optimal harvest time differs among years. Weather conditions are discussed as one possible cause of pod shattering

Section: Spring Turnip Rapementioning

confidence: 99%

Seed loss as a result of pod shatter in spring rape and spring turnip rape in Finland

Pahkala¹,

Sankari²

2001

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“…Due to high variation during sowing time (Peltonen-Sainio and Jauhiainen 2014), drought taking place e.g. by mid-May, may in one year facilitate sowings in the case of late soil drying, while in another year it may, together with elevated temperatures (see Peltonen-Sainio et al 2016b) cause too fast a soil drying, uneven seedling emergence and plant stand establishment (Mukula and Rantanen 1987, 1989, Pahkala et al 1994, Hakala et al 2012. Spring cereals have a very limited capacity to compensate for reduced seedling number by tillering, because long days inhibit tillering (Mela andPaatela 1974, Peltonen-Sainio andJärvinen 1995) and thereby support uniculm plant stands (Peltonen-Sainio et al 2009).…”

Section: Discussionmentioning

confidence: 99%

“…Spring cereals have a very limited capacity to compensate for reduced seedling number by tillering, because long days inhibit tillering (Mela andPaatela 1974, Peltonen-Sainio andJärvinen 1995) and thereby support uniculm plant stands (Peltonen-Sainio et al 2009). Contrary to this, turnip rape (Brassica rapa L.) and oilseed rape (B. napus L.) may compensate for low number of seedlings per land area by branching without any marked yield losses (Pahkala et al 1994).…”

Section: Discussionmentioning

confidence: 99%

Spatial and temporal variation in weather events critical for boreal agriculture: II Precipitation

Peltonen‐Sainio

Pirinen

Mäkelä

et al. 2016

There is great temporal and spatial variation in precipitation in Finland. Both drought episodes and repeated, abundant rains may interfere with crop growth, yield and quality formation, and many agricultural operations (such as tillage, sowing, crop protection and harvesting). The windows for optimal operations are often narrow due to the short growing season and variable weather conditions. Field traffic at high soil moisture may e.g. cause soil compaction. Also, the high environmental footprint on agriculture under high latitude conditions is often attributable to fluctuations in precipitation. The station-wise precipitation observations from the Finnish Meteorological Institute for the time period of 54 years (1961‒2014) were interpolated to a regular 10 km × 10 km grid covering the whole country. Several successive time slices were used to calculate the likelihood of: 1) drought periods and 2) periods with repeated rains with above normal precipitation sum so that both of these lasted for at least a) two weeks or b) three weeks. We demonstrated substantial spatial and temporal variation in the likelihood of drought and repeated rains: drought episodes were common during the early half of the growing season, while again repeated rains with high accumulated precipitation (lasting for two weeks) became common in the latter part of the growing season. Though, we highlighted in this paper some examples of how these events may affect agriculture and their environmental impacts, the datasets published here may be applied for many other assessments.

“…The relatively small number of fungus infected, non-viable seeds in germination tests likely demonstrates that there was no particularly marked loss of viability in early sown seeds, knowing that turnip rape is able to yield adequately also when only half the sown seeds germinate and establish a stand (Pahkala et al 1994). Such a >50% germination capacity was recorded frequently (Tables 1 and 2) -with only few exceptions when Poligen  -coating was used.…”

Section: Peltonen-sainio P Et Al An Alternative Sowing Time For Tumentioning

confidence: 93%

“…Alternative sowing method is of interest also under northern European conditions, where not only is the growing season very short, but early summer drought often results in uneven seedling emergence (Pahkala et al 1994). The uncertainty related to germination and seedling emergence is particularly emphasised in turnip rape, as small seeds are sown into the rapidly drying soil surface at about 2-3 cm depth.…”

Section: Introductionmentioning

confidence: 99%

Polymer coated turnip rape seed did not facilitate early broadcast sowing under Finnish growing conditions

Peltonen‐Sainio¹,

Känkänen²,

Pahkala³

2008

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An alternative sowing time for summer turnip rape (Brassica rapa L. var. oleifera subvar. annua) and canola rape (Brassica napus L. var. oleifera subvar. annua) was investigated under northern European growing conditions, where the growing season is very short and seedling establishment in spring is difficult. Using a method termed carrier technology, seeds of spring canola were coated with polymer and sown in winter or early spring. Two types of polymer were tested: water-impervious Poligen  WE3 (polyethylene wax at five rates depending on experiment) and water-soluble, freeze sensitive Extender  (GrowTech at 3% of seed weight). Four separate field experiments at two locations (Jokioinen, 60°81'N and Mietoinen, 60°38'N) and two laboratory experiments were carried out in [2002][2003][2004]. Early sowing times were used in combination with autumn control of weeds using non-selective herbicides and broadcast sowing onto cereal stubble to promote cost-efficiency. Such sowing method failed to produce even plant stands, as only few seedlings emerged. The polymer coatings were successful and the water-soluble, freeze sensitive polymer designed to allow an alternative sowing time performed well in laboratory tests. Large numbers of early sown coated and control seeds remained viable until the end of spring. Under field conditions germination or seedling establishment failed probably due to poor seed-to-soil contact. Moreover, unfavourable winter and spring conditions likely resulted in lack of synchrony between adequate temperature and water availability needed for seed imbibition and germination.