Mapping suitability for Tuber melanosporum growing in Patagonia, Argentina - an opportunity for agriculture diversification

Aim of the study: The wide variety of climates, with significant gradients and abundance of microclimatic patches, and the vast diversity and availability of soils in Patagonia, suggests that there are extensive areas suitable for the cultivation of Périgord truffles (Tuber melanosporum Vittad.). The promotion of truffle cultivation as a profitable, off-season option for marginal and idle lands requires the identification and quantification of suitable areas on a regional scale. The objective of this study was to generate a regional map of areas suitable for the cultivation of T. melanosporum in Patagonia and a detailed map for the province of Chubut, using GIS data on physical and chemical soil characteristics, climatic variables and vegetation cover. Area of study: The Argentinian Patagonia region (1,060,631 km²). Material and methods: Two truffle suitability maps that include edaphic, climatic and vegetation cover requirements, together with irrigation availability, were developed: a Patagonia regional map (scale 1:10,000,000), and a Chubut province detailed map (scale 1:40,000). Both were built and analysed with Google Earth Engine (GEE) and validated with field ground truth points. Main results: The suitable truffle growing area considering soil, climate and surface water availability is 2,680,000 ha for Patagonia region and 489,877 ha for Chubut province. The Chubut province map delimited suitability patches more accurately than the regional map, reducing the surface mapped as suitable while confirming the high potential for T. melanosporum cultivation of the valleys associated with the Mayo, Senguer and Chubut rivers. Research highlights: The regional map indicates that T. melanosporum cultivation is feasible in 3% of Patagonia surface, considered together patches classified as suitable and suitable with surface-water irrigation. This regional model clearly identified major limiting factors in different parts of the region, such as temperatures in the northernmost and southernmost parts of Patagonia, the presence of ectomycorrhizal forests along the Andes Mountain range, and the critical role of water resource availability. The map of Chubut province showed that the model was useful not only for regional scale planning but also for more detailed purposes such as farmer’s decision making, while taking into account the significant small-scale variability of Patagonian topography and soils. These maps are pioneering for Argentina, constituting a powerful decision-making tool for territorial planning, aimed to diversify agricultural production in Patagonia by incorporating this novel and profitable crop in vast areas.