Division 5.3 Causal link between the geographical area and the quality or characteristics of the product (for PDO) or a specific quality, the reputation or other characteristic of the product (for PGI)

The characteristics of the ‘Patata di Bologna’ PDO, such as its smell, flavour and the intense colour of the potato itself and of its skin, are the result not only of genetics but also of the environment in which it is grown (soil, climate, cultivation techniques, storage conditions), hence the clear link of the ‘Patata di Bologna’ to the Province of Bologna. Potato-growing in the Province of Bologna has a long tradition, thanks to the area's particularly suitable soils, the excellent quality and organoleptic characteristics of certain varieties and the traditional cultivation techniques used by growers. The potato-growing tradition in the Province arose from the need to feed the population, particularly when wheat harvests were poor (wheat invariably being seen as a staple food) and from the conviction that potato-growing would be of benefit to the Province in the sense that it would no longer have to rely on food purchased from elsewhere. The link was gradually strengthened through the hard work of the growers, who developed step by step almost perfect cultivation methods, increasingly efficient equipment adapted to the product, cutting-edge techniques for storing the product and marketing structures able to exploit fully the product’s commercial and quality characteristics, thanks in particular to the high level of specialisation in the area.

Thanks to the special environment, a result of the interaction between the soil (pedology and hydrography) and the climate (rainy during the autumn-winter period, with moderate spring temperatures from as early as the end of February and optimal temperatures, i.e. around 25 °C, during the formation of the tubers), the potato grown here develops physical characteristics (texture, grain size) as well as organoleptic characteristics (particular smell and flavour) giving it a particular quality.

As described in a work by Contri (1817), the soils of the Province of Bologna are suitable for potato-growing because potatoes thrive in ‘low land, already drained and raised by alluvial deposits’, characteristic of the Province's reclaimed land. Changes to the land over time have produced lowland areas of alluvial deposits from rivers and streams originating in the Apennines and still flowing today. These soils have a medium to fine texture, a good depth and are well drained. They are alkaline, contain organic material and are rich in the nutritional elements essential to potatoes, such as potassium which is present in large quantities, phosphorus and nitrogen. Such conditions are ideal for growing potatoes, not least by virtue of their bunched roots, lack of a taproot and their dense system of root hairs.