Section 5 Case studies - Weeds Australia

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Nick Jacobs DECC Polaris ranger used for serrated tussock control in steep intractable land. Increasing fertility: In 1988, John tried applying Mo-superphosphate (molybdenum added) in tussock infested areas as well as seeding sub clover to increase fertility of the soil. This technique resulted in a reduction of serrated tussock and an improvement in pasture. Aerial spraying: In the early 1990s, John participated in an aerial spraying exercise with a neighbour. He had about 10 ha of land sprayed using a helicopter, using flupropanate at the rate of 2 L/ha. The unfortunate result was a total kill of grasses and a significant reinfestation of serrated tussock and colonisation by acacias. A subsequent aerial spraying exercise some years later that used a lower flupropanate rate per hectare over ripped paddocks more selectively controlled the serrated tussock. Revegetation: John revegetates areas that have been cleared of serrated tussock to prevent reinfestation. With the help of Greening <strong>Australia</strong>, John has now planted 9000 pines (6000 have survived), and direct seeded 24 ha of land on the escarpment with natives including tea tree and wattle. Some serrated tussock agronomists in the NSW Department of Primary Industries (NSW DPI) advocate the use of tea trees (Leptospermum spp.) to provide continuous, competitive cover against serrated tussock on intractable land. “Tea tree is often seen as a problem as it recolonises cleared country,” notes Luke Pope, NSW DPI District Agronomist in Cooma. “However, when the cost of keeping an area clear of serrated tussock is greater than what the land is making, it is best to rest the area from grazing to allow natural or actively planted tea tree to dominate.” The result All land managers continue to experiment with different methods of control and agree that there seems to be no permanent solution to the serrated tussock problem in steep intractable land. 96
Tea tree being used to out-compete serrated tussock in “difficult” country. DECC is proud of their achievements in the Merriangaah Nature Reserve. This reserve is part of the Snowy River Area and consists of 5652 ha of steep and intractable land, and flatter country cleared in earlier years for pastoral use. Serrated tussock control efforts have reduced the large infestations that existed within the western boundaries at the time the Reserve was gazetted. “Merriangaah Nature Reserve is an entirely different place to when it was taken over. The major known infestations are under control and further spread into the Reserve or onto neighbouring properties is minimal. In the more open areas there is evidence of healthy competition from native grasses and shrubs,’ comments Nick Jacobs from DECC. All land managers have learnt from past mistakes. They all emphasise the need for continual vigilance against reinfestation, accurate mapping, ensuring that there is good replacement ground cover and the appropriate use of herbicides In areas where farmers have followed NSW Department of Primary Industries advice of promoting tea tree regrowth, serrated tussock has become less of a problem, reducing the cost and time of controlling the weed. There is also evidence that, after some years, the tea trees dominate and form dense canopies that prevent seeds blowing into areas uninfested by serrated tussock. The future “Follow up is the key to success,” says Nick Jacobs. DECC has an annual program in known sites that consists of two to three days of effort to mop up small numbers of mainly single serrated tussock plants. Occasionally staff find previously unknown pockets of infestation, which are then incorporated into a new control regime. In a recent planning exercise, John formalised his long-term goal to contain the spread of tussock on his farm and, if possible, eliminate the infestation altogether. Depending on the topography and productivity of the land, he will continue to use a range of techniques such as: • continuing to increase soil fertility using fertilisers such as zinc, gypsum and trace elements to condition the soil and help promote desirable species • increasing the accuracy of spreading fertiliser through the use of a 4WD tractor using a GPS guiding system • increasing the biomass cover in conjunction with reducing grazing pressure on the paddock • strategic fencing for grazing management and animal hygiene • undertaking strategic burns to reduce serrated tussock seeding and seedbanks. Luke Pope 97
Page 1 and 2: Section 5 Case studies 1. Changing
Page 3 and 4: Hand pulling: All farm vehicles are
Page 5 and 6: Case Study 2 Pasture management Sum
Page 7 and 8: Case Study 3 Controlling serrated t
Page 9: Case Study 4 Tackling serrated tuss
Page 13 and 14: Urban serrated tussock infestations
Page 15 and 16: Case Study 6 Cooperative approach b
Page 17 and 18: The result According to Council, as
Page 19 and 20: Results of careful glyphosate spot
Page 21 and 22: The result No serrated tussock plan
Page 23 and 24: Case Study 10 Serrated tussock stra

Section 5 Case studies - Weeds Australia

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