We must first consider that: to cultivate truffles there is no single science. This is not a simple crop, plus the development of this fungi occurs underground, so we’re not really seeing what is happening. The truffle is a ectomycorrhizal fungi that lives closely associated to the roots of their host trees (Oaks) and as such, this fungi in its vegetative stage is developed on input of nutrients provided by your host, who will then transfer these nutrients while the fungus help to capture soil minerals and water. The complexity of this relationship and its maintenance over time is that if the tree alone is able to easily obtain these mineral nutrients and water, it ceases to depend on the fungus, so this can be moved easily by other fungi competitors always on the lookout . The interesting thing is that if we want to Grow truffles and this fruiting we need to manage conditions (soil environment) which in principle are complicated for the normal development of the trees by themselves, ie. If we favor certain situations of water stress and nutrition (for the tree host).
The truffle is a fungus that after the last glacial period was adapted to live in temperate mediterranean environments of Southern Europe (sanctuaries of this fungus in the last glaciation) where the climate typically has well defined seasons (hot summers and cold winters) , in addition to special regimes of rainfall with some periods of drought during the year.
Today, these areas where truffles occur naturally, present a calcareous soil conditions that have high pH and calcium levels, important factors for the development and nutrition of the fungus. Moreover, this fungus, unlike the common mushroom, was adapted to live underground where he finds a suitable environment for their development (associated with the roots of their hosts) and fruiting, interacting with various organism, but the clear problem that in order to spread, the need of animals to detect and consume so disperse their spores, reproductive strategy that has led to this fungus to be able to emit volatile compounds (aroma) so that their natural vectors can be attracted (eg The Boar). All these factors have led to the truffle is a very rare fungus, besides that its development has an important biological complexity, both from the standpoint of genetic and environmental, with many interactions between different factors.
It’s really early in the nineteenth century, when starting the truffle growing with the French farmer Joseph Talon, which links the existence of truffles with the proximity of the oaks, advising family and friends “if you want truffles planting acorns, “being in the second half of the nineteenth century when France began to be published in the first treatises of truffle and truffle production is important in this country.
This method considered traditional crop of acorns that fall under oak trees that produce truffles and planting of new plots. Subsequently there were changes that were based on letting these acorns germinate under the trees and seedlings were transplanted new. The principle is that the seedlings were germinated under the oak trees naturally infected from truffle spores present and the same mycorrhizal truffle associated with the host tree, so these plants were new mycorrhizal and truffle producing then be planted after years (8 to 10). With this method was reached several thousand hectares in France, mostly coincided with the phylloxera invasion (in Vineyards), where many of these vineyards extracted, were replaced by plantations of truffle trees. There are some official reports (Chatin), indicating that in those years in France, the truffle production exceeded 1,000 tons per year (Golden Age of truffles). What happened?, later from the first and second world war has been a catastrophic decline in truffle production, and today there are even less than 100 tonnes in Europe (France, Spain and Italy). Despite advances, based on the development of methods of controlled mycorrhization (years 70), production levels have failed to recover, even with these new methods have been planted over 10,000 hectares in Europe from the 80’s. The explanations are many, but the reality today is that the global annual production does not exceed 100 tons, plus good performance although there are some plantations in Europe, even in other countries where cultivation has been introduced (NZ, Australia, Chile, USA) there are plantations that produce very little and some that produce nothing. Where is the problem?. To my mind, after several years analyzing this issue, I think within the main reasons we must consider the following:
1 .- The quality of the inoculated trees produced in nurseries: Because this fungus is associated through its mycorrhizal host tree and this is a complex biological relationship, before thinking of cultivating truffles we must ensure that the plants we use are a high degree of mycorrhization, and this delicate association can easily fail later in the field, due to several factors. Recently in several countries (within and outside Europe) have appeared several nursery companies to promote truffle growing and they offer mycorrhizal plants grown in greenhouses, which are subsequently acquired by established producers and agricultural land. The complexity of this is that inside the head of a normal, common sense says you are buying a plant (oak, hazel, etc.). That the future will produce truffles, without thinking that what they really should purchase or acquire it a fungus (the truffle) that is inserted into the roots of plants. The problem is that most of the future truffle growers who buy plants in order to cultivate truffles in the future, virtually do not differentiate one from another truffle (there are different species, including some that are indistinguishable to the eye), less able to recognize mycorrhizae truffle (This requires “some practice and a good microscope”), then it is possible that in all the plants are getting poorly mycorrhizal levels or plants without mycorrhizal truffle and worse, completely plants infected with other truffle species and / or contaminant mycorrhizal fungi, which can easily be accidentally introduced in nurseries either by carelessness or negligence, lack of control or inexperience of the nursery. The plants are expensive, then the most important concern is to acquire plants produced by experienced truffle nurseries and ideally that plants have a mycorrhizal truffle guaranteed by any independent and qualified body.
Currently, several countries (USA, Italy, France, Australia) have plantations are known “supposedly made with Truffle mycorrhizal Plants (T. melanosporum)” which have produced the Chinese truffle (T. indicum) unscented and without economic value , Tuber Brumale and other species, which have been accidentally introduced into plantations “Moreover, there are several plantations that produce very little and others “produce nothing “then this issue is paramount and it is advisable to evaluate well and make sure to purchase certified plants or guaranteed by an entity independent and qualified in the subject. The recommendation here is: The producers should require external quality controls to the nursery to prove: Levels of black truffle mycorrhization, and certify the species by PCR techniques. NOTE: THE HEIGHT OF THE PLANT IS NOT RELEVANT. 15-25 cm HEIGHT ARE BEST PLANTS, AND SPECIALLY WELL HARDENED. PRODUCERS ARE BUYING A FUNGUS. NOT PRETTY PLANTS
2 .- A second important aspect is the proper choice of land and climate which seeks to establish the crop: The truffle is a fungus adapted to live and flourish in very specific soil and climatic conditions. There is ample bibliographic material which describes the ecology of this fungus, which is key to begin understanding how it develops and how to cultivate it. Failures in various plantations around the world, could also be explained by a wrong choice of field planting. Among the most important factors we consider when choosing a site are properly:
• Physical conditions of soil texture, structure, aereation, depth, rock, etc..
• Physiography, topography, exposure, slope, etc..
• soil chemical conditions: pH, cations, mineral elements, organic matter, C / N
• biological soil conditions: Little studied but within the most important.
• Previous land uses
In short, we consider all these factors and also their interrelation, in order not to err in the election. I emphasize that this is a very complex culture, unlike others, so we should not ignore these important factors. Currently truffle plantations are being established in countries outside Europe, with a reasonable level of success, where natural soil conditions are different from those found in natural areas of Europe, however with agronomic techniques, these soils can be modified and adapted successfully to produce truffles. The problem here is that not all soils can be modified sucesfully to be conducive to truffles and also successful producers jealously guard their experiences and techniques, obviously, hence the recommendation for new producers in these new truffle corners ( USA, NZ, Australia , Chile, Argentina, etc.) is appropriate advice from professional specialist and / or producers with expertise.
3 .- The third important point we must consider that if we want produce truffles properly and “we do not lose even socks” we must understand very well that the management techniques in new plantations, must be adaptes and recreate very specific ecological conditions required by the fungus (humidity, temperature, physical-chemical aspects of soil, etc..) plus a good understanding of the biology and reproductive aspects of truffle interact with their hosts. These latter factors do not operate independently, there are many interactions and also we have many aspects still unknown, especially in relation to biological aspects of soil and how they affect the development and fruiting of the truffle, issues where there is a great field to research order to improve production worldwide. If we consider that the traditional farming methods there were more truffles than today, with all the supposed advances What can we infer from this?. We look back to understand better. In those years in France, rural life in the countryside, traditional agriculture and livestock allowed to maintain ecosystems and environments much more favorable for truffle fruiting, especially the typical multifunctional land uses of those years (sheep grazing, firewood exploitation, charcoal production in the forests, ancient vineyards, etc.) that favored environments for truffles, open forest type pastures, natural grassland formation, in addition to the techniques used in traditional agriculture had a much lower impact on soil due to less intensive tillage, with virtually no use of chemicals.
Summarising all this, my final conclusion is: Why not look back? So to understand more in that is failing today. There are many issues to consider and what matters is that “If we want to TRUFFLES” we must first understand all these aspects.