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

Abstract

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.

Effect of seed coating on plant growth and soil conditions: A preliminary study for restoration of degraded rangeland in the Qinghai–Tibetan Plateau, China

“…2006; Medeiros et al. 2006), the polymers could have a negative impact on germination (Peltonen‐Sainio et al. 2006; Mangold and Sheley 2007).…”

“…Rapid germination and emergence will allow the coated seeds to establish quickly. Even though many researches reported that germination of seeds coated with hygroscopic polymers enhanced germination (Arsego et al 2006;Medeiros et al 2006), the polymers could have a negative impact on germination (Peltonen-Sainio et al 2006;Mangold and Sheley 2007).…”

Emergence of Polymer‐Coated Corn and Soybean Influenced by Tillage and Sowing Date

“…Polymer coatings are used in the agriculture seed industry to improve hybrid corn production and for relay cropping (Lessiter, 2000). In addition, polymer‐coated seed offers the possibility of extending the growing season of spring crops in cold regions by sowing seed in winter or earlier in the spring (Gesch and Archer, 2005; Peltonen‐Sainio et al, 2006). Temperature‐activated polymers change structure at a critical temperature; this change in structure also causes a change in permeability of the polymer (Hicks et al, 1996).…”

Applying granulated and hydrated hydrophilic polymers at sowing to sustain seedling establishment of spring turnip rape

“…oleifera DC.) (Peltonen-Sainio et al 2006), sowing is best carried out when soil temperatures are c. 10°C (Pahkala 2003). Combining an optimal temperature regime with other conditions that favour germination is challenging.…”

“…Winter sowing would lighten the workload and provide moist soils for germination, but winter crop types lack sufficient winter hardiness for Finnish conditions. However, using carrier technology, by sowing polymer-coated seeds during the preceding autumn, winter or very early spring (Kirkland & Johnson 2000;Karamanos et al 2002;Clayton et al 2004;Johnson et al 2004), did not prove successful under Finnish conditions when combined with broadcast sowing (Peltonen-Sainio et al 2006). Therefore, the problems in turnip rape production that are linked with uncertainty about seedling establishment need other solutions.…”