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Halophyte agronomy on dryland saline areas in south-west Victorian high rainfall districts

N. Badawy, G. Whipp and H. Ward

Department of Agriculture, 78 Henna St., Warrnambool VIC 3280
Department of Agriculture, PO Box 406, Hamilton VIC 3300

Dryland salinity, the most serious environmental threat to Victorian agriculture, is already invading numerous locations throughout the State including its south-west high rainfall districts. High concentrations of dissolved salts usually find their way to the upper layers of the soil profile through rising watertable, capillary and evaporative actions. In south-west Victoria, however, the harmful effects of elevated salinity levels in the root-zone are often exacerbated by seasonal waterlogging and/or adverse soil structure. The use of halophytes to productively utilise salt-affected lands is rapidly gaining a global momentum amongst agriculturalists from arid and semi-arid zones, including Australian farming and scientific communities. In regions with annual rainfall above 600 mm and a 'Mediterranean-like' climate, such as South-west Victoria, information on halophyte agronomy is inadequate. In that region, the mean annual precipitation ranges from about 550 mm to >900 mm/year and the farming systems include sheep, beef cattle and dairy cattle.

Our research program is currently investigating the use of halophytic plants as a component of a viable and sustainable agronomic system for the management of salt-affected lands in South- west Victoria. A number of introduced and native Australian saltbush (Atriplex) and bluebush (Maireana) species are being assessed for their survival, growth and agronomic performance. Other research aspects include improved productivity through better establishment techniques and the use of fertilisers. Soil management systems best suited to various locations with problems ranging from salinity to sodicity and/or waterlogging are also being developed.

Although research recommendations are still emerging, preliminary data (Table 1) indicate that careful species selection and seedbed mounding are valuable tools for successfully revegetating salt-affected lands. Each of these tools plays a different role in the overall management of these lands. The value of identification of the limiting factors for the specific site to be utilised for halophytic agriculture cannot be over emphasised. This is crucial if, indeed, an economically and environmentally sustainable system is to be developed for the successful revegetation of these saline discharge zones.

Table 1. Species survival (%) before and after waterlogging.

Acknowledgements

This project was jointly funded by the National Soil Conservation Program (NSCP) and the Victorian Salinity Program.

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