Landcare Soil

The importance of soil type

· Guest post by Timothy Doolan ·

Something to think about when choosing native plants for your garden or revegetation project is which plants are suited to your soil type.

There are a number of different soil types in the Townsville region. Higher quality soils are generally found along waterways and their immediate floodplains, e.g. Hermit Park, Mysterton, Mundingburra, and poorer quality soils are generally up on the flood free flats, eg Kirwan, Currajong, West End.

Townsville soils overall are typical of much of Australia with poor nutrient and water holding capacity, highly leached. This is yet another reason why Local provenance native plants are so important, as they are adapted to the local soil types as well as the local climate.

But even local plants can be subject to high variation in suitability given a patchwork of local soil types and the wonderful diversity of biomes within the greater Townsville region. So, which species for which soils?

Back in the 1970s there was a comprehensive soil survey of the Townsville region, with the results freely available online at the Queensland Government Publications website. Short of getting your own soil survey done, this is probably the best macro level source of information. There is also an accompanying ‘Land Capability Map’ on this site which gives brief comment on the agricultural merit of the different soils surveyed.

In general, the poorer quality soils of flood-free areas are more suitable for the ubiquitous Australian dryland species (gums, wattles, grasses), and the better quality ‘younger alluvial’ soils will more easily sustain a diversity of species and a more ‘rainforesty’ type of garden.

Of course, soil type is just one factor to consider, but it can definitely help with minimising water use, ensuring good plant growth and promoting a healthy ecosystem and native biodiversity.