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

Abstract

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 >> Cascade birdsfoot trefoil = Kara cocksfoot > Hakari brome = Dryland birdsfoot trefoil = Redquin red clover > > 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