Effects of drilling depth on seedling growth of seven dryland pasture species

Abstract

<jats:p>The effects of sowing depth on the seedling growth of three dryland pasture grasses and five legumes from an on-farm trial in the Hakataramea 'Valley, South Canterbury was examined. The drill was set to sow seed at depths of 10 mm, 20 mm, or 30 mm depending upon species, but in practice a wide range of drilling depths occurred. Seedling growth was highly correlated with sowing depth for the majority of species. The level of dependence of seedling growth upon sowing depth for the species examined was as follows: Tetra alsike &gt;&gt; Cascade birdsfoot trefoil = Kara cocksfoot &gt; Hakari brome = Dryland birdsfoot trefoil = Redquin red clover &gt; &gt; WL 320 lucerne = Maru phalaris. In general, seedling growth was good from sowing depths of less than 12.5 mm and extremely poor from depths greater than 25 mm. A prediction of the relationship for these species on the basis of seed weight was not possible. Keywords sowing depth, pasture species, dryland species, seedling growth, hypocotyl length, epicotyl length</jats:p>

Over-Drilling New Zealand Tussock Rangeland with or without a Previous Legume Phase

“…Collectively the series of trials show that good establishment of 'improved' pasture grasses remain problematical for over-drilling of tussock grassland. The more successful was cocksfoot (present trial; [2][3][4][5][6]).…”

“…Those treatments included: with or without a previous development legume dominant phase; sowing method (surface broadcast, disc drill, or experimental drill giving partial cultivation); prior herbicide treatment; use of starter nitrogen fertiliser; fertiliser placement in relation to seed; sowing season; grass species and accompanying legume species [2][3][4][5][6].…”

NZGA President's Address 2019 - Smarter pasture renewal plus objective thinking

“…Thom et al 2011), and sowing depth (e.g. Woodman et al 1990). But there are few papers and little research on how farmers set a renewal level (Stevens et al 2007).…”

Low cost overdrilling technology for pasture establishment

“…The drills that have been tried also lack the control of seed placement depth which is important for successfully introducing improved pasture species into this country (Woodman et al 1990;Seaney & Hensen 1970). Single disc drills rely on spring pressure to achieve penetration and are not sensitive to changes in ground contour or changes in the surface vegetation.…”

“…The commonly used triple disc drill suffers from the above problems and also loses depth control when the leading disc rolls over s tone or rock. Hoe type drills used for direct seeding often have the tines fixed to a rigid chassis and therefore the individual tines are not able to follow changes in ground contour (Woodman et al 1990).…”