Information about the characteristics of the other varieties of truffle that grow in the particular soils would be useful. This can be from practical – for example clay is hard to clean off and assessing the quality of the truffle without washing is almost impossible. Truffles growing in the loose soils of trenches or wells come out very clean and have a rounder shape.
This is an illustration you’ll find in most Truffle Growing texts. Usually it is shown as a single variety, here we’ve over-layed Tuber melanosporum, Tuber aestivum and Tuber borchii. Different varieties of truffles suit different soils. There’s often an overlap and some variation can be made within soil types, with increasing drainage by deep ripping, adding crushed rock etc. If you’ve seen where your soil texture sits on the Texture Triangle page, see here where that sits with the varieties that are commonly available from our nurseries, and below, one that we hope isn’t.
Remember, these were graphed from the types of soils where wild truffles of these varieties are found in Europe. If we collect enough data on Australian soils we may create our own overlays but there are some things we know are ‘truffle truths’, eg. heavy clay soil forces truffles to the surface and retains water which encourages rot.
An (intended) outcome of this is to alert you to the possibilities of growing multiple varieties in your truffière. Or if you can’t (silty clay for example doesn’t suit ‘bianchetto’). You will still have to raise the pH up to 7.5-8.00, which is an easier task in the loam soils than it is for clay heavy soils. There will often be areas on your land that suit one or other varieties better. Work with your soil.
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Missing your Tuber brumale? Historically, before we could DNA test our inoculum to be sure it has only the desired variety, T. brumale entered the country. Even now, some nurseries are producing trees with untested inoculum and will almost certainly have cross-contamination. It suits almost all soil types, and there are realistic concerns it can out-compete and take over an existing plantation. It’s difficult to remove. and if even if you were to grow it as a sideline (hard to sell, and at a lower price), you risk it overtaking your melanosporum and becoming your main crop, thus the concerns about the presence of T. brumale.
Soil types
In a land of acronyms see the CSIRO ASRIS (Australian Soil Resource Information System map. Use their Viewer and turn on only the suitable soil types with lower clay content. There is an interactive website that explains the soil classifications used in that ARIS map, here on the CSIRO site. See The Classification tab.
Note the red areas of these maps are Kastanozems soil which have a naturally high pH (7.4). These soils may well require little liming other than to kill the competing mycorrhizas, and no ongoing ‘top-ups’. (Which is not much use if you already have chosen your property). Here’s an example of the maps that are are included as layers in our Treasure map.
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Resources used for this page
The preference areas of the chart were taken from Taming the Truffle Hall, Brown and Zambonelli 2007. The map images are from the CSIRO ASRIS website
The long tail of these varieties fits well with the producing areas in Western Australia. Sandy loams to clay loams with 10-30% clay content. Many of the soils in the Manjimup area contain pea gravel which provides good drainage but this can affect the shape of the truffles. Truffles obtained from soils with less gravel may be rounder and have better shape.