Alkalinity and structure of soils determine the truffle production in the Pyrenean Regions

Abstract

Aim of study: The program "Typology of truffle stations in the Pyrenean Regions" aimed to define the ecological conditions and culture practices that favor Tuber melanosporum growth and fruiting in this area.Area of study: Navarra, Catalonia, Midi-Pyrénées and Languedoc-Roussillon.Material and methods: The program was based on the survey of 212 wild and cultivated truffle beds of evergreen oaks (Quercus ilex). The data collected in the field consisted of photographs, samples of soil, roots and mycorrhizae, and information on cultural practices followed by truffle growers.Main results: (i) truffle soils are alkaline, from neutral, dolomitic, to moderately or very calcareous soils; (ii) truffle soils are light, well-structured and stable to water immersion; (iii) mycelium that colonizes roots survives in suboptimal conditions, but it does not necessarily bear ascocarps. Finally our results suggest that T. melanosporum is a relatively ubiquitous fungus able to grow, or at least to persist, in a wide range of physical and chemical soil conditions. We propose a probabilistic model of the environment favorable for fruiting, built around a two-dimensional graph with an axis for the chemical conditions, like soil alkalinity, and another axis for the physical conditions, like soil structure. Research highlights: Soil alkalinity and structure allow to built a convenient representation of the ecological capacity of a place to be good T. melanosporum habitat, and thus of the probability for truffle growers to harvest truffles according to the environmental properties of their truffle orchards.Keywords: dolomite; limestone; mycorrhizae; Quercus ilex; field survey; Tuber melanosporum.

Soil Properties Conducive to the Formation of Tuber aestivum Vitt. Fruiting Bodies

“…The analysed soils varied from "heavy" (up to 55.4% clay) to "light" (up to 46% sand). The great diversity in soil texture at T. aestivum sites is well documented in the literature [11,19,20,24,25]. The "light" soils are generally thought to be less favourable for truffle cultivation.…”

Soil Characteristics for Tuber aestivum (Syn. T. uncinatum)

“…Thus, the range of soil pH in water where T. aestivum fructifies (5.9 to 8.4) is quite similar to the pH of soils where Tuber melanosporum Vittad. is harvested (5.5 to 8.4) (Jaillard et al 2014; see Chapter 11).…”

Lack of Linkages among Fruiting Depth, Weight, and Maturity in Irrigated Truffle Fungi Marks the Complexity of Relationships among Morphogenetic Stages

“…In the experimental site, three replicate blocks of 0.25 ha with different soil textures were selected in a soil gradient along a 300-m-length transect line, with block 1 having sandy loam texture, block 2 having loam texture and block 3 having loam/clay loam texture ( Table S1 ). Although in the wild black truffle is found in almost every type of texture, this texture gradient is representative of the range of common soil textures in black truffle cultivation [ 23 ]. The three blocks were managed with the same agronomic practices.…”