Mapping terroirs at the reconnaissance level, by matching soil, geology, morphology, land cover and climate databases with viticultural and oenological results from experimental vineyards

This work was aimed at setting up a methodology to define and map the «Unités Terroir de Reconnaissance» (UTR), combining environmental information stored in a Soil Information System with experimental data coming from benchmark vineyards of Sangiovese vine.

A Soil Information System stored geography (reference scale 1:100,000) and attributes of i) land cover, ii) lithology, iii) morphology, iv) soil typologies, v) soil properties, vi) soil geography, vii) long term average Winkler bioclimatic index and average rainfall, and viii) appellation of origin area, of the whole Province of Siena. Soil functional properties were selected and classified after a statistical analysis of the relationships with the viticultural and oenological results obtained in 69 vineyards over a time span of 2-5 years. All the vineyards of the province were grouped in terms of lithology, morphology, and soil functional properties, so as to create homogeneous UTR. The result was that the whole province was characterized by 363 UTR, which covered a total of 16,650 ha, each UTR having a size ranging from 2 to 474 ha. The GIS map highlighted and explained the environmental diversity of viticultural areas of the province, providing information about peculiarities, constraints and potentialities of each UTR.