Use of Native Plants for Bush Grazing
Throughout Australia's semi-arid rangelands, the pastoral industry is largely dependent on stock having access to indigenous flora for food - principally in the form of native grasses and herbs. Such grazing is usually carried out on Crown lands over which people have been granted non-exclusive licences for pastoral use.
The situation is very much different in Victoria. While stock feed in the form of native grasses was largely responsible for the European settlement of the State, this is no longer the case. The great majority of the agriculturally productive lands of the State were sold and, as the native grasses were eaten out, modified by the introduction of alien grass and clover species and subject to fertiliser regimes, clearing of overstorey vegetation and, in places, irrigation. Thus the role of native plants for pasture is now very much reduced. There is no `rangeland' country in Victoria,234 and currently limited grazing on public lands.
The majority of remnant native vegetation in Victoria is on public lands. While much of this has been subject to grazing to at least some extent in the past, extensive areas of such remnant vegetation are now included in national parks and other nature conservation reserves, with grazing excluded on the basis of incompatibility with the management objectives of such land uses. Two notable exceptions are grazing in alpine areas and along river frontages.
Native grasses and herbs of the Victorian alpine area are very palatable to cattle (and sheep - although these have long been prohibited on soil-conservation grounds). The vegetation of these alpine meadows and the understorey of surrounding forests are used for grazing for periods of up to 12 weeks each year, in summer and early autumn. Outside this period the cattle are moved to lower country to be fattened up and sold. The licensed grazing blocks are used to supplement the capacity of the private lands used by licence holders235 - while important to individual operators their economic importance is minimal on a State scale.
Native vegetation also remains on much of the public land abutting most of the State's watercourses, land originally excluded from sale to ensure free public access to water. This vegetation is grazed under the authority of river-frontage licences, originally issued to help adjoining landowners avoid the costs of fencing - a reason still important for most licence holders. All such grazing is subject to defined stocking rates and compliance with certain conditions.
While native plants are thus of limited economic importance for pastoral use in Victoria, there are, however, some areas where native grasses are now being shown to have advantages over exotic species pasture. The advantages arise from both grazing production and from the point of view of soil conservation.236 Lands with approximately 350-600 millimetres yearly rainfall, such as between Echuca and Goulburn, have been shown to be suitable.
A number of native Australian grasses are also being used on salinity-affected land. The primary focus of salinity control in Victoria is to ensure that recharge areas are well covered with perennial vegetation that uses rain as soon as it falls, rather than allowing it to reach the water table. Recharge areas, especially in the north-east of the State, are often rocky and dry. The only exotic grasses that can be established on such sites are usually annuals, which need fertilisers to maintain them. It is difficult and generally uneconomic to establish such grasses. Annuals are also unable to use the first rains of autumn, as they must re-establish each year.237 However, native perennial grasses, in particular wallaby grass (Danthonia spp.) and weeping grass (Microleana stipoides) are commonly present in these areas. They can be managed or resown as economic and effective alternatives. Being perennial, they are able to use rain as soon as it falls and so reduce recharge.238
In discharge areas salt-tolerant native shrubs can be used to lower water tables, provide feed and protect soils. The Committee saw saltbush used in this way in South Australia. As salinity is reduced, perennial native grasses, such as wallaby grass, can be introduced between the shrubs. This provides additional fodder, water use and soil protection.239
Native Fodder Crops
The productive value of a number of native shrubs as fodder crops has been rediscovered in recent years. Interest has been renewed in increasing productivity in areas of low rainfall and as drought fodder, as well as for applications such as reduction of water tables, erosion control and to increase productivity of saline soils. Saltbush is the main species being currently targeted - it is deep rooted and has a high drought and salt tolerance. While an array of saltbush species occur in Australia, the most commonly used species is oldman saltbush (Atriplex nummularia).
The Committee visited Western's Nursery in Renmark. It specialises in the production of saltbush. Ironically, after a number of years of selecting plants best suited for palatability and production, Western's Nursery found that seed stock obtained from South Africa was the best - it was apparently introduced to South Africa in the late 1800s from Australia. As germination from seed is difficult, the plant is generally sold as seedlings. Western's Nursery's success as a major supplier of saltbush was facilitated by their previous nursery experience and parallel development of an efficient mechanical planter.
The Committee also inspected a property that had been using planted saltbush since 1996.240 The owner found that it can increase the carrying capacity of marginal grazing land by up to 20 fold. The Committee is also aware that use of saltbush is being trialled in parts of Victoria - around Nhill and Pyramid Hill.
Methods for the best planting strategies and management of grazing are still being developed. Further selection of plants could enhance yields, protein levels, palatability and bushiness. It is also possible to harvest the fodder and pelletise it - plantation production of such pelletised food may be commercially viable.241 Saltbush is well suited to alley farming systems, which are described elsewhere in this chapter.
Other shrubby species planted as stock food within Victoria include:
a) golden wreath wattle (Acacia saligna);242 and
b) river saltbush (Atriplex amnicola).
These species are palatable, fast growing and, most importantly, recover well from grazing (but require stock exclusion during establishment).243
Tangled lignum (Muehlenbeckia cunninghamii) has been used by one Loddon Valley dairy farmer to feed cattle, provide shelter from chilling winds, lower water tables and reverse salinisation of soils.244
Other Potential Crop Species
Greening Australia drew the Committee's attention to the potential for crops based on native species:
Victoria has a range of deep rooted perennial native legume species which have considerable potential for selection and development for farming purposes, to possibly assist with dryland salinity control and to provide productive options in areas where introduced legumes will not persist ... native grasses also offer some possibilities.245
Examples of potential crops are:
a) purple glycine (Glycine latrobeana), which is related to the introduced soybean (Glycine max) - native glycine species can grow in frosty and low-rainfall areas outside the range of the introduced species and could be used to create productive cultivars;
b) some of the species of scurf peas (Psoralea) - a deep rooted legume with potential as fodder and `pulse' crops;246 and
c) weeping grass (Microlesana stipoides), whose seed is very similar to wild rice grass - it could be grown as a cereal crop in areas unsuited to existing introduced crops and would require lower inputs. 247
