SALTBUSH: IT'S a failure as living haystack insurance against drought, and while it will grow on saline land, it isn't economically productive there. But it does have a significant role to play in our western cropping/ farming systems.
So says Peter Milthorpe who's spent six years at Condobolin Research and Advisory Station in central western NSW working to determine the best role for this almost mythical Australian species.
prevention better than cure
"There's no doubt that Oldman Saltbush, the species we've concentrated on, will grow on saline country, but it's not productive there. I believe that prevention is better than cure and that we can use it to improve the perenniality of our pastures in this part of the world and reduce the risk of dryland salinity, " says Mr Milthorpe.
"More importantly it has the potential to give stockmen in this area more flexibility. It could allow them to turn wether country into lamb-breeding country and it will grow cattle. What we need to do now is learn how to manage it. "
Mr Milthorpe is currently working with a group of landholders who have differing amounts of Oldman Saltbush on their properties. They're involved in a range of activities from grazing deer to cattle to wool and mutton production. The largest has about 1, 000 hectares under Oldman Saltbush and the aim of the project is to study management techniques paddock by paddock.
"Saltbush is a very high-protein fodder plant, " says Mr Milthorpe. "The protein content may be as high as 18 per cent, but whether all of that is usable depends on what's available with it. Saltbush needs to be fed with an energy source — grass, hay, grain — something like that and stock have to be 'taught' how to graze it and given time for the specific gut flora needed to digest the plant to develop.
"Sheep are used to grazing along the ground. They need to lift their heads to graze saltbush. Until they do, they will hammer whatever is growing between the shrubs and leave the saltbush alone. It's one of the reasons why you can't simply put stock on and off saltbush pasture — they need time to become used to it. That doesn't mean that you don't shift stock around, but once they're acclimatised to it, they need to be shifted to other paddocks with saltbush. "
Drought relief needs management too
While Mr Milthorpe believes that saltbush has a significant role in reducing drought risk, he doesn't see it as a 'living haystack' drought reserve. "Besides the need to get stock used to it, you also need to manage the shrub to get the best value from it, " he says. "Older leaves lose their nutritional value and the shrubs need to be grazed regularly. In the case of sheep, they need to be kept at around 1. 2 metres for best results.
"The great value of saltbush in managing drought risk is that you can see the feed ahead of you and plan stock numbers accordingly. Lucerne will produce feed in response to rain but, once it dries off, it will lose its leaf and become dormant. Saltbush retains its leaves, you can see what feed you've got. "
Perhaps surprisingly the salt load in the shrub actually increases productivity to a point. "However, once it goes past that, stock begin to lose condition. The quality of water available to stock is important, " says Mr Milthorpe, "as is the need to have an energy source available with the saltbush. Lactating ewes with access only to saltbush will 'go off very quickly. "
Alley cropping and salt management
Mr Milthorpe is planning trials involving 'alleys' of saltbush. The aim is to plant about 20-25 per cent of the paddock to saltbush in rows or alleys with pasture established between the alleys. In a cropping phase, the intervening pasture would be removed and the saltbush left in place. "I think that plantations of as little as 2. 5-5 per cent of the farm area planted to saltbush will prove to be economically viable, " he says.
Asked to rate the shrub on its ability to dewater country, he says that over time it will dewater country as well as any other woody perennial, but "it acts differently to eucalypts or wattles. They use water quickly and, when they reach wilting point, they shut down and exist on what's available. Saltbush is a very efficient user of water, making slow but efficient use of what's available over time. "
Therefore, weed control is of the utmost importance, especially when new plantations are establishing.
Making the most of what you've got
"The great value of the species may be its place in an infrastructure already established. People are looking to establish new industries based on pine plantations or mallee production to protect this country from developing dryland salinity. Those industries will need whole new infrastructures to develop. In saltbush we've got a species that can be very valuable to the industries that already exist. We just need to learn how to manage it. "
Contact: Mr Peter Milthorpe 02 6895 1016