The Mid Torrens Catchment Group- 10 years of supporting NRM activities

The Mid Torrens Catchment area covers over 10,394 hectares and includes the sub catchments of Kersbrook and Cudlee Creek and the main channel of the River Torrens. The Mid Torrens Catchment also encompasses both Millbrook and Kangaroo Creek Reservoirs.

Since its inception in 2000 the Mid Torrens Catchment Group (the Group) has committed itself to a long term goal of working closely with local landholders and State Government agencies to restore and preserve the River Torrens ecosystem through enhancing biodiversity and water quality.

The Group, through funding and technical advice, has helped landholders to achieve whole of property improvements through projects which protect remnant vegetation, create habitat for native flora and fauna, protect and enhance riparian and non-riparian zones, revegetate with local native plant species and fence off riparian and remnant vegetation areas.

The Group also has a strong involvement with the community and has been involved with education programs which encourage sustainable land management practices and the creation of a sustainable ecosystem.

The Group has had many achievements over the past 10 years, including the case study below which is one example of how the support of the Group contributes to natural resource management (NRM) outcomes in the catchment.

If you would like to learn more about the Mid Torrens Catchment Group go to www.midtorrens.com.au or for further information on an NRM Group near you please contact your local Board office based at Gawler, Lobethal or Willunga.

INFORMATION GATHERING THE KEY TO SUCCESS FOR SMALL LANDHOLDERS

Prepared by: Georgina Keynes, Land Management Adviser, Adelaide and Mount Lofty Ranges Natural Resources Management (NRM) Board

Property location: Kersbrook

Property size: 30ha/ 76 acres

Current enterprise: Prime lamb production

Rainfall: 800mm/annum

Soil: Clay loam

Features: Well designed and implemented property plan, dams and watercourses fenced to exclude stock, exotic trees removed and on-going woody weed control, extensive re-vegetation program with local native species and the commencement of a perennial pasture renovation.

With advice and support from the Mid Torrens Catchment Group the owners have, over the past three years, transformed their property into a productive system which is not only sustainable but also contributes to the biodiversity of the region.

Issues

When the property was purchased three years ago it was one large paddock consisting of four on-stream dams, watercourses choked with exotic trees such as poplar, willow and ash and dotted with woody weeds like blackberry and briar rose. The pastures were comprised of guildford grass, broadleaf weeds and some annual grasses which died off in the summer months leaving the soil prone to erosion. The property was also quite barren, with the only remnant trees being Eucalyptus hiding among the weeds in the watercourses (Figure 1).

Actions

Property planning

The owners’ main priority was to fence the property into smaller, more manageable paddocks and to fence off the dams and watercourses. They attended training events provided by the Adelaide and Mount Lofty Ranges Natural Resources Management (NRM) Board and developed a property plan that incorporated and prioritised actions to include both their requirements and the most sustainable outcome for the land.

It was through this connection with the Board that they were introduced to the Mid Torrens Catchment Group who has provided continual support and guidance to achieve NRM outcomes on the property.

Watercourse and dam management

With support from the Catchment Group the owners embarked on upgrading the sustainability of the property by improving the water quality. They began by removing the exotic trees and woody weeds from the watercourses using the ‘drill and fill’ method for the large trees and shrubs and ‘cut and swab’ for the smaller weeds. These methods ensured that there was no off target chemical damage and that small amounts of chemical were used. The owners have found that weed control is ongoing and are still controlling poplar suckers and a determined blackberry bush.

The watercourses and on-stream dams were also fenced off, allowing at least 5 metres either side of the watercourse to allow for revegetation using reeds and rushes close to the waters’ edge and shrubs and trees further out. The fencing has also made allowances for stock crossings which have been constructed taking into account the stability of the ground, watercourse line and flow.

Fencing off the watercourses has also allowed the owners to effectively divide the property into smaller paddocks which leads to more sustainable pastures when combined with a rotational grazing system.

Revegetation

One of the stand-out features on the property is the revegetation of the riparian and unproductive areas (Figure 2). The owners gained advice and information from the Group in order to plant a range of trees and shrubs which are locally indigenous (native) to the area, this has ensured the plants they use are adapted to the environment and provide habitat and food for local native flora and fauna. They have also collected seeds from local native plants in the area allowing them to grow many of the plants themselves.

Most of the trees and shrubs were planted in winter and guarded using milk cartons, which protect the plants from grazing pressure of rabbits and kangaroos and also from heavy frosts which occur in the area. In some of the more waterlogged areas the owners have found it beneficial to plant during the summer time; although the plants require supplementary water they do not need to contend with the waterlogged conditions of the winter.

Pasture management

The pasture on the property currently consists of many unfavourable species. After gaining advice from local agronomists and the Board, the owners have decided to begin a pasture renovation program beginning with the highest priority, the weediest paddock, first.

The owners are following a two year plan beginning with a soil test completed in summer which has resulted in biodynamic compost being spread over the entire property to correct the nutrient deficiencies. This will be followed up with weed control in the spring and early autumn next year.

Guildford grass is one of the more difficult pasture weeds to control as it grows from a bulb and thrives in low fertile soils. The addition of compost coupled with herbicide application applied in late July when the bulb is exhausted has helped to control the weed which will allow the new perennial pasture to be sown in autumn next year.

Pest control

Rabbits have been a large problem on the property and it has taken an integrated approach using baiting and warren destruction to control them. Also the removal of woody weeds such as blackberry has helped to decrease the numbers.

Results

Thanks to the help of the Mid Torrens Catchment Group the owners of the property have gained practical advice and support in order to begin the transformation to a sustainable property boasting well vegetated watercourses which add to the biodiversity of the region.

Within the next few years the owners should also be able to increase their stocking rate as a result of well managed perennial pastures which will increase the overall profitability of the property.

Key things learnt over time

A pasture renovation program must be planned out over at least two years to ensure good weed control, particularly for paddocks with guildford grass
Weed control is a continual battle which requires ongoing maintenance
Correct fence placement saves you time in the long run by allowing easy movement around the property
There is a lot of help and support available and it is extremely important to share ideas
Not rushing in; taking the time to develop and implement a well thought out plan

NRM in perspective

Ensuring good water quality is a one of the crucial factors in the success of this sustainable property. Fencing off watercourses and the removal of weeds has lead to erosion control and allowed the establishment of native vegetation to provide a buffer to the watercourse and add to the biodiversity of the region.

Determining what vegetation community should be established on site has been important to provide habitat and food for local birds and fauna.

The use of perennial pastures not only helps to control weeds and reduce the risk of soil erosion, it also helps to reduce salinity problems caused by a rising water table.