Legumes drive productivity in dryland pastures, but to reap the benefits of these protein-rich plants, it is important to select the right legume for the right environment.
On-farm factors such as the duration and frequency of summer and autumn droughts, rainfall distribution, evapotranspiration, soil depth, the potential for flooding, soil fertility and pH should all be considered when selecting legumes for specific farm environments.
Farm landscapes within a property can be separated into zones such as dry, moist, north and south facing and the appropriate legume selected to optimise production within each zone.
With the appropriate fertility and grazing management, legumes will thrive and persist in the environments most suited to their needs.
Lucerne
Lucerne should be planted in the deepest soils, as its long tap root gives the plant the ability to source water stored deep within the soil profile.
For an optimal six paddock rotation, an area of 20-30ha can be sub-divided into six paddocks. Lucerne should be sown in October at 10kg bare seed/ha. To ensure nitrogen fixation, the seed will need to be inoculated.
Subterranean clover
Subterranean (sub) clover is particularly suited to dry zones, where pasture growth is typically compromised for four or five months over summer and autumn.
These areas have an annual rainfall of less than 700mm and often have shallow, stony soils with a low water-holding capacity.
Sub clover can be used as the primary legume in grass-based pastures. An example of a pasture mix for these zones is 10kg bare seed/ha of sub clovers (5kg/ha mid flowering and 5kg/ha late flowering) with 2kg/ha cocksfoot.
Intermediate zone
In this zone, growth is compromised by a lack of water for around three to four months in an average year, usually between December and March. These areas have an annual rainfall of between 620-900mm.
A combination of ryegrass, cocksfoot and sub clover can be sown on the sunny faces while white clover can be added to the mix on shady faces. While white clover may survive most summers, sub clover generally outyields white clover in these environments.
A basic seed mix for this zone is 10kg bare seed/ha sub clover (5kg mid-flowering and 5kg late-flowering varieties) along with 2kg/ha cocksfoot or 5-10kg/ha perennial ryegrass. Two kg/ha small leaf white clover can be added to the mix for south hill faces and areas holding some soil moisture.
Moist zone
In this zone, water stress seldom exceeds three months and usually occurs between January and March. White clover produces well in these areas and while yields may be similar to or exceed those of sub clover, sub clover’s cool season production means that it may offer more flexibility with livestock production such as lambing ewes.
A basic seed mix for this zone is 10kg bare seed/ha sub clover (5kg mid-flowering and 5kg late-flowering varieties) along with 2kg/ha cocksfoot or 5-10kg/ha perennial ryegrass and 2 kg/ha small leaf white clover.
Very wet/flood prone areas
In areas that saturate or flood, a yannicum-type sub clover (sub-species well suited to wet soils) such as Napier or Monti would be ideal. These can be sown at 5kg/ha along with a standard sub clover.
Establishing legumes
Before establishing legumes, soil tests should be carried out, particularly looking for phosphate (P) and pH levels.
Applications of P fertilisers and/or lime may be necessary to ensure soil fertility is sufficient to allow the legumes to reach their yield potential.
More information
- Pasture mixes for Dryland Farming systems (PDF, 235KB)