Sub clover available to farmers after 40-year delay
A subterranean clover adapted for East Coast hill country farming systems is being made available to farmers after decades of sitting on the shelf.
Spelling will allow the subterranean (sub) clover plant to setseed by burying seed burrs. With sufficient autumn rainfall, the seed will then germinate and ultimately grow a bank of high-quality feed in late winter and spring.
Sub clover produces 90% of its drymatter in spring which is ideal for lactating ewes and driving higher pre-weaning growth rates of lambs. It also fixes nitrogen which increases the quality and palatability of pasture grasses.
Sub clover thrives in sunny, low rainfall, dryland environments and will survive on summer dry sites where white clover may struggle.
To make the most of sub clover, pastures need to be actively managed to achieve 80% ground cover of sub clover. This will ensure the protein-rich clover makes up 40-50% of the total dry matter on offer.
This management includes spelling up to 20% of the sub clover paddocks or blocks every year to allow re-seeding.
This means either closing the areas up completely or lightly stocking with cattle to retain pasture quality. Sheep find sub clover very palatable and will dig the seed burrs out of the ground and eat them, hence the need to shut them out of areas selected for re-seeding.
After spelling, the areas should be grazed hard over summer and autumn. This is particularly important in autumn as open pastures (700 kg DM/ha) will aid sub clover germination after rainfall. Germination is triggered after a rainfall of at least 20mm.
Autumn is also the best time for over-sowing sub seed to either augment resident sub clovers or introduce cultivars with complimentary characteristics. For example, the Woogenellup cultivar start flowering in early to mid-September, so introducing the medium to later flowering Leura or Puawhaa, (the latter has been bred specifically for NZ hill country) can extend the time sub clover is productive.
