Dry Inland Areas
Let us keep this to the areas defined as the ‘Wheatbelt’ at this stage, where it is possible to successfully establish Leptospermum plantations provided there is supplementary irrigation applied during the drier warmer months. There is no reason, therefore, standing in the way of developing a project in the drier regions of the country.
Given that these plants are not particularly fussy about soil quality the main limitation then becomes the availability of water. There are of course other limitations and barriers to be concerned with such as vermin control and suchlike.
The adaptability of these plants, although early days, is indicating that this is entirely possible based on some trial plantations (typically 5 – 10ha in size) throughout the Wheatbelt regions (and beyond) throughout the drier parts of Australia.
South Australian Wheatbelt. Spacing 4m x 2m. Drip irrigation provided with (in this case) limited water from a reticulated supply of River Murray water.
Groundwater will be suitable depending on the salinity levels. These plants typically have lower-end medium salinity tolerance possibly around 1,000 EC units. Other factors such as the soil infiltration rate must also be taken into account. (see salinity guidelines)
These plants require only a fraction of the water needs of conventional irrigated crops such as rice and cotton and a lot less than virtually all other horticultural crops.
The average annual (predominantly winter) rainfall in the trial site area pictured above is 380mm with hot and dry summers. The pH of the sandy soil ranges from prox 7.0 to 8.0 through the profile. (Information regarding pH levels)
This is Leptospermum polygalifolium subsp polygalifolium grown from selected populations of parent plants from coastal NSW. This is also a demonstration of the adaptability of these plants.
These plants were planted as 15cm high seedlings 10 months before the time the image was taken. Note the very high survival rates, the obvious health and vigour and excellent weed control by the owner all contributing to the likelihood of a positive outcome into the medium and longer term.
The significance of being able to establish these systems in the cereal growing regions is self-evident.
To begin with, the issue of site security can be assured by locating in an isolated area. The land will be relatively cheap, and the entire project can be integrated into an existing farming operation.