Alby Schultz (Hume, Liberal Party) Share this | Link to this | Hansard source

I rise to speak on a threat to Australia’s agricultural sustainability. That threat is the rapid and uncontrollable spread of noxious weeds, in particular Nasella trichotoma, or serrated tussock, as all farmers, graziers and rural landholders commonly know it. Serrated tussock is one of our country’s worst perennial grass weeds. It invades pastures, native grasslands and urban areas courtesy of its amazing ability to disperse its seeds over great distances, and it is rife Australia wide. It is a native of South America and is a plant that has great capacity to survive and further expand its spread. It can tolerate extremes of temperature, low rainfall and low soil fertility, which makes it perfectly adaptable and comfortable in Australia. With its prolific seed production and ability to spread by wind, livestock, machinery and transport networks it is well suited to rapidly advance over new areas in the temperate zone, colonising bare patches of ground and changing landscapes forever.

Serrated tussock has the ability to cause a greater reduction in livestock carrying capacity than any other species in Australia, reducing pastures that carry seven to 15 dry sheep equivalent per hectare to a carrying capacity of only 0.5 dry sheep equivalent per hectare. Add to this the ability of a single mature plant to produce more than 100,000 seeds per year with light seed heads able to travel great distances by wind, perhaps up to 20 kilometres, and you have a serious problem. While wind is the primary natural method of seed dispersal in the serrated tussock plant, human activity now plays a significant role in its spread. Seed heads can be caught and transported by vehicles, machinery, tractors, implements, spray units, mowers and slashers. Its seeds attach to the fleece and fur of livestock and other animals, and may also be picked up in the mud on animals’ hooves.

Livestock will generally avoid eating serrated tussock. However, if they do graze on it while in seed, the animals can spread the seeds through their droppings and the seed can survive in the gut of ruminant animals for up to 10 days, making it possible for tussock to spread long distances. Serrated tussock seed can contaminate crops, hay, silage, grain and seed. Movement and use of contaminated produce can lead to the development of new infestations, as can the movement of soil from an infested area.

You may ask how this information is relevant to my opening statement of a threat to Australia’s sustainability. The answer is quite simple: serrated tussock covers more than two million hectares of land in south-east Australia and has the potential to spread even further, with a potential distribution estimated at 32 million hectares across Australia. Given that Australia needs good arable land for agriculture to meet the country’s food needs, the spread of tussock during the drought and, more recently, increasing spread due to recent rains has seen the control of tussock become near impossible. Whilst the federal government has developed a Weeds of National Significance program, in which state governments and local councils are also involved, it is recognised that the responsibility for the control of all noxious weeds lies with the landowner. What is less recognised is the phenomenal costs associated with noxious weed control and that governments of all levels are landowners as well.

The Serrated Tussock Working Party for New South Wales and the ACT estimates that in New South Wales alone serrated tussock costs more than $40 million per year in control and lost production, and when the majority of that $40 million is spent by private landholders, most of whom are primary producers, it is easy to see why the problem never seems to reduce. Whilst governments provide some monetary assistance through their various programs, they are not able to manage noxious weed programs on their own land. This in turn impacts on private landholders, especially those neighbouring public land. They continually fight a losing battle when that neighbouring land is not always under a weed management program because of a lack of resources. The fault here lies with successive governments, both coalition and Labor, and unless they work more cooperatively with state and local governments and the private landholders in a proactive rather than a reactive way the menace will keep spreading, placing ever-increasing stress on our food bowl by smothering good productive pasture land.