Truffles, mushrooms and mycorrhizas
© Truffles and Mushrooms (Consulting) Ltd                     
Selecting a suitable location for growing an edible mycorrhizal mushroom
Selecting a suitable location for cultivating an edible mycorrhizal mushroom
Climate, choice of host plant, and soil chemistry, texture, drainage and organic matter content will all contribute to the success of a plantation established to cultivate an edible mycorrhizal mushroom.  For some of the truffles and a few other edible mycorrhizal mushrooms we have some idea of their ecological requirements but for the vast majority of the 1000 plus species we don’t have a clue.  Between these extremes are species like porcini and chanterelle where we have some information available but have yet to learn how they might be cultivated.

In the attached table (143 KB pdf file) are rough comparisons of the climate in centres adjacent to natural and artificial Périgord black, Burgundy, Italian white and bianchetto truffle truffières.  From this it can be deduced what species of truffle might suit other locations.

Almost all truffles require a relatively high pH soil.  Naturally high pH soils are common in Europe and found in areas where there is much limestone - a vertical section of a soil developed over limestone is shown to the bottom left.  Although these are less common in countries like Australia and New Zealand, research has shown that a high soil pH can be created artificially simply by mixing large amounts of lime with a soil.  So the next step in checking the suitability of a site is to analyse soil samples to determine if the soil is suitable in its natural state, if it can be modified, and if there are any other issues that might cause problems after planting.  

Soil sampling
A.  Use a soil auger about 25 mm diameter (see www.fao.org/docrep/field/003/E7171E/E7171E12.gif) to sample the soil to a depth of 250 mm (don't use a dirty auger or one that has paint flaking off it).  Alternatively if you don’t have access to an auger a trowel can be used.  Take samples from 20 spots around the first block avoiding soil around water troughs, gates, headlands, trees, dung or urine patches, stock camps, abnormally wet or dry spots, or other areas likely to have abnormal fertility.  Put the soil from the holes into a clean plastic bucket.  When you have taken all 20, thoroughly mix the soil in the bucket and put about 1 kg into a labelled, thick-walled, zip-lock polythene bag.  Seal the bag.  Repeat for any other areas you wish to be analysed.  Please note that the costs for analysis on the next page are per bag of soil.

B.  In natural truffle soils the pH of the subsoil usually increases with depth as you get closer to the parent rock.  Similarly a layer of acidic volcanic ash or loess may have been deposited over the top of the limestone in the distant past so that the pH of the soil reflects this acidic layer rather than the underlying limestone.  In these situations and others where the soil changes with depth it is important to sample and analyse both the topsoil and the subsoil.  Consequently, two bags of soil are needed - one from between 0 and 12 cm and the other from between 12 and 25 cm.

C.  If the area to be planted is quite large (more than a hectare) and the soil changes across the site, the area should be divided into sections that appear similar and one of the above procedures carried out for each section.

What to do with your soil sample(s)  
Print off a copy of the next page and fill in your details.  Put your samples in a cardboard box or robust plastic mailer bag along with the completed form.  If you can please include the name of your soil type, a map showing the location of your property, a note about the drainage characteristics of your land, and anything else that may help us.  Then within 24 hours of sampling send either by Courier Post (only available through New Zealand Post Shops) or Fastpost to: Dr Ian Hall, Truffles and Mushrooms (Consulting) Ltd, P.O. Box 268, Dunedin 9054, New Zealand.
A section of a rendzina soil developed over limestone.  Often there are pieces of  limestone in the topsoil.