Saltbushes are a dominant and important component of natural ecosystems in low rainfall and arid regions of Australia. They are an ideal and frequently chosen species for lowering watertables and reclaiming saline land. Some species of saltbush are recognised as valuable forage for livestock.
The largest of the Australian saltbushes is old man saltbush, Atriplex nummularia (Lindl.). It is a very hardy, perennial shrub adapted to a wide range of environments. It can grow to three metres high and 2–4 metres wide, has thick leaves that are silver-grey in colour, and its woody stems are generally brittle. Old man saltbush is extremely long-lived and records indicate that some plants are over 100 years old.
The value of old man saltbush as a forage plant for sheep and cattle was recognised by graziers in the mid-1800s. However, overgrazing of natural stands, extended drought through the 1940s and the added grazing pressure of rabbits saw widespread depletion of saltbush in rangeland ecosystems.
Remnant stands and new on-farm plantings have maintained the reputation of the species as a valuable supplementary forage, especially in late summer and autumn when annual and perennial pastures may be depleted. While saltbush is a valuable forage source, it should account for no more than 30–40% of the diet at any time because of its high salt and sulphur levels.
There is increasing interest in developing perennial-based grazing systems for low rainfall areas and for a changing climate when rainfall may be less predictable and dry periods extended. Old man saltbush is likely to be a key species in these systems. Old man saltbush is also a key species for salt-affected land where waterlogging is not a problem.
Many farmers claim that meat of stock grazed on saltbush has the marketable benefits of leaner, richer, moister and better tasting meat, compared with the meat of stock that haven’t grazed saltbush. There is scientific evidence of lambs grazing saltbush prior to processing having leaner carcasses with higher meat yields and higher vitamin E levels. Vitamin E is associated with maintaining meat redness and extending shelf-life.
Facts and figures
- Members of the saltbush family of plants, Chenopodiaceae or chenopods, grow naturally all over the world
- Old man saltbush is one of 250 species world-wide belonging to the Atriplex genus of the saltbush family, and one of 61 species in Australia
- Bluebush, a species common through the arid areas of Australia, also belongs to the family Chenopodiaceae
- The hardiness and adaptability of old man saltbush in arid environments has led to its exportation to many arid and semi-arid parts of the world
- It is important that old man saltbush is used as supplementary feed and it should account for no more than 30–40% of the diet at any time because of its high salt and sulphur levels
- Saltbush provides a good source of protein and minerals at a time of year when pasture and crop stubbles are often depleted and of low quality
- The life of a well-managed saltbush plantation could be productive for over 70 years and poorly managed stands may only last 10–12 years
Saltbush is grown extensively in saline systems in the cropping zone of Western Australia. Increasingly, it is being planted on soils that are marginal for cropping in the low to medium rainfall zones of all the southern states and southern Queensland.