Truffles, chestnuts and acid soils


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Last Saturday I went to hunt truffles to Tarragona, in an area rather peculiar. Peculiar because truffles (melanosporum and brumale) fruit naturally on licorella (a kind of slate rocks) acid soils with no carbonates and pH of 7 or below.

In the picture you can see the chestnut tree under which we gathered Tuber brumale. A few years ago, chesnuts were good truffle producers, but over 10 years ago Tuber melanosporum no longer fruits there. Chestnut trees have canker and have been dying and thus truffles underneath. The new shoots coming out, they die in a few years and there is not enough time to generate new truffieres.

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Chestnut tree does not produce a burnt due to the amount of litter and debris that accumulates on the ground. In fact, truffles come under the leaves, as does Tuber uncinatum in beech forest. Black truffles, when used to fruit in those chestnut trees, were numerous but small in size (as a brumale). Tuber aestivum appears to be very rare in chestnut out in that area, although I remember the summer truffle had been described in northern Portugal under Castanea.

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We finished the day hunting Tuber melanosporum under holm oaks in the same area were licorella has an acid reaction. Studies of these areas, which are already underway, can give valuable information, especially for growing truffles in the southern hemisphere, where the truffle is growing artificially in acid limed soils.
In another post I will explain the “trick” to make this happen and practical consequences for truffle growing on acid soils.
Hugs,
Marcos S. Morcillo

About trufflefarming

CEO of Micofora. Truffles and edible wild mushroom science and farming. Researcher, truffle farmer & mycologist
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21 Responses to Truffles, chestnuts and acid soils

  1. nw2350 says:

    A nice story Marcos – we in the Southern hemisphere await your further findings with interest!

  2. Joan says:

    Wonderful! Enjoy reading your blog.
    I’m a fan from Seattle, WA ~ Joan

  3. evenaarj says:

    I am curious to hear about the trick……… Sounds promising for the truffle cultivation in the the Dutch mountains….. Thanks again for the interesting blog, Marcello

  4. Francisco says:

    Really interesting Marcos, opening new chances for cultivating truffles in chesnut groves and/or even in neutral or subacid soils as for T. borchii? I am intrigued in your works about this since I am working with relictic chesnuts stands between Madrid and Ávila, and as a way of mycorrhizal enhanced Systemic Acquired Resistance against Phytophthoras on chestnuttrees.

  5. Thanks. I’ll keep you updated when the paper will be published, as we got some great discovers analyzing the soil samples under chestnuts, that somehow may change truffle farming on acid soils, and why not, even using chestnuts. tuber borchii is extremely agresive, so it could maybe be used as a target specie against Phytophtoras…
    Cheers
    Marcos

    • Francisco says:

      Thank you Marcos. Yes, please, keep me updated about any publications of your researchs on this issue. T. borschii interests me specially, since it seems to be the most adequate truffle for the soil conditions in my zone, and what you say, the possibilities to be helpful to fight the Chestnuts Ink Disease (and at the same time to have a valuable truffles prodction, of course). Mycorrices of boletus and amanistas show some effectiveness and I am already considering tests with trichodermas, fosfonates (potasium and magnesium fosfits; T. borschii,could be another good chance
      Best regards,
      Francisco

    • yanis kostopoulos says:

      Hi Marcos, i’d love to hear more about any new insights on truffle (melano) production in acidic soils.It’s a subject that puzzles me for some time. I’d greatly appreciate it, if you could alert me when your paper on the subject is published.All the best.

      • Yashu Yanis,

        Efharisto poly for your comments!
        Some clues on what it seems it is happening with pH and carbonates….
        With the burn the total carbonate disappears, decreasing the effervescence in the hydrochloric acid that the fungus dissolves in active lime. In this regard, a nutritional hypothesis states that in soils already saturated in calcium the fungus uses this active lime to stress the tree. It has been shown that as the amount of truffle mycelium increases so does the calcium ion. This could have an effect in blocking nutrients such as phosphorus, which the tree would not be able to assimilate without the presence of the truffle. In this case what we have is not a symbiosis but rather a kind of parasitism with consent. In other words, the truffle uses calcium to ‘hijack’ the tree to produce sugars and vitamins. In return the truffle solubilises certain nutrients and gives them to the tree in very small doses.
        The summer truffle has been seen to have a very similar effect in making the total carbonate disappear. However, in this case, instead of increasing the calcium and the active lime, it raises the pH (by up to 0.3 points), which, in the end, has a similar stress effect on the tree, and in some cases even leads to evident chlorosis, as the tree literally no longer has access to nutrients.
        Cheers,
        Marcos

  6. yanis kostopoulos says:

    Hmmm, interesting.I am no stranger to the notion that “the truffle creates its own environment inside the brulee” and i understand how carbonates are used to remove CO2 from the ground and increase the oxygenation of the mycelium, creating in the process active calcium.
    However, what puzzles me with chestnuts is that they are trees that grow in a pH of 4,5-6,5 (clearly acidic) and more importantly are very sensitive to the presence of calcium in the ground; they seldom do well when total carbonates are >2%.So, given that the melanos use the total carbonate reserve in the ground and gradually turn it to active calcium, how can they do well with a host like the chestnut that does not like the presence of carbonates in the ground to begin with?
    I don’t think an increase of the pH by 0,3 is enough to turn the typical chestnut environment into a pH that a melano prefers.Possibly in cases when chestnuts grow marginally in almost neutral pH, such a small increase around the tree could help create a (marginal again) environment for the melano.But i am sceptical that a typical chestnut grove could be used as a host for a typical melano plantation; their optimal environments are just too different.
    Anyway, it is always great to read your thoughts on anything truffle related.Muchas gracias.

    • Dear Yanis,
      I do not think chestnuts should be used as a host trees for growing truffles. Those chestnuts with natural truffieres have its main and deeper roots on acidic bedrock, but the surface soil layer has some lime so neutralizes pH.
      It looks that maybe is not the total amount of calcium or a pH treshold, but the slight change in that natural levels that can be used for the truffles. Thanks again for your interest and comments.
      Cheers
      Marcos

  7. yanis kostopoulos says:

    Marcos, this:
    “It looks that maybe is not the total amount of calcium or a pH threshold, but the slight change in that natural levels that can be used for the truffles”
    is fascinating as a premise.I am sure that you realise the room for experimentation on this and the concept of “hijacking”, that it opens.There are many “weird” places where truffles grow, that can’t be explained normally.Again, all the best, Yanis.

  8. you´re right, but note this is just an hypothesis! it´s true that specially in good years, truffles fruit wherever they want.
    cheers,
    Marcos

  9. truffie says:

    Hi Marcos, what altitude where those chestnuts at?
    Cheers!

  10. truffie says:

    Did the holm trees with Tuber melanosporum on acidic soil produce burnts? Just asking because I’ve seen burnts many times on these kind of soils and the dog found nothing. I always thought they were produced by some kind of hypogeous fungi but not truffles.
    Thanks.

  11. yes, they do! but note there are so many different mycorrhizal fungi that produce something like a brule (i.e. Astraeus sp)…not all that glitters is gold 😉

  12. truffie says:

    Hi Marcos! We need another post about truffles on acidic soils. Let us know what you have discovered during the last few months. Amazing stuff!
    Cheers.

  13. 🙂
    we found more and more sites, specially in Girona area where truffles fruit on slightly acidic soils. We have taken more soil samples, specially from Tuber aestivum sites now and repeat sampling on the chestnuts and holm oaks truffieres, but now taking leaves from trees that produce truffles and trees without truffles, to analyze the levels on calcium on tissues, to check if the Calcium is really arriving to the tree, and from now most analysis give positive, so it keep us “over the line” for the theory…
    nothing published yet, sorry for that.
    cheers,

  14. K says:

    Hi Marcos,

    Is there any news about the topic?

    Thnaks,
    K

  15. Pingback: Is it possible to multi crop chestnuts and truffles? | trufflefarming

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