The research ”At the discovery of Piacenza lands and treasures” carried out by the researchers of the Fruits-Viticulture Institute of Università Cattolica del Sacro Cuore, the expert pedologists of I.TER, the contact people and partners of the Roads of Wines and Tastes (Strade dei vini e dei sapori) and the technical advisers of Riserva Naturale Geologica del Piacentino.
The characteristics of the soils are described in brief herein.
The clayey lands of Val Tidone
The hilly landscape, between approx. 200 and 400 metres above sea level, is characterised by the gentle slopes cultivated as vineyards. The toponymy of some towns, like Creta and Calcinara, is linked to the particular nature of the soils, that had already been exploited in Roman times to produce bricks and tiles, as proven by the ancient kilns found in the area.
The work in the fields exalts the grey colour of the land, which derives from the colour of the rock.
Clayey soils prevail that range from fairly to extremely deep, and there are also calcareous, fairly alkaline soils.
The high content of clay (>40%) confers good fertility properties to the soils and favours swelling and shrinking phenomena. In fact, in rainy seasons, the clay retains water and increases the volume. While with the summer heat, the clay dries and cracks.
Ancient Red lands (Terre Rosse antiche)
Pasture and vineyards prevail in less sloping and flat areas. In the vineyards, the rows generally face North-South to favour increased sun exposure of the grapes. Since the soils are very ancient, they are called ‘’paleo-soils’’ and are of reddish colour tending to orange, well visible in the fields after ploughing at the end of the summer and during the autumn. The reddish colour was determined by intense evolution processes, due to the oxidation of the iron and accumulation of ferrous-magnesian concretion of black colour.
The Lands of Basso Appennino
The landscape is characterised by a series of undulating fairly steep slopes, alternated by Apennine rivers at the bottom of the valleys. Since these are in general young soils, not fully evolved and similar to rocks of calcareous origin, these are mostly calcareous and slightly alkaline.
Agricultural activities exalt the colour of the soils, which also vary significantly according to the geological origin of the rocks: greyish colours characterise soils that formed in clayey rocks, brown-yellowish colours are typical of soils that formed in arenaceous rocks, and various colours combined to extravagant purple, greenish and grey streaks are typical of rocks so called ”multi-colour clays”.
The Lands of Medio Appennino
Cultivations are generally carried out at the bottom of the valleys and on the less steep and more stable surfaces of the slopes: sowable lands and pastures prevail, but there are also vineyards.
The soils were formed with materials derived from sedimentary rocks, consisting of calcareous-marly opal –arenaceous stratifications, by mostly clayey and marly compounds, and mixed calcareous, arenaceous, ophilite rocks.
They boast a slope that goes from fairly to extremely steep, ranging from 20 to 70%; they are of medium texture, pebbly or extremely pebbly in the deep layers, in general well drained. Forests prevail on steep and very steep soils, mainly coppiced woodlands featuring oak and chestnut trees. There are many abandoned chestnut groves; vineyards are also present.
- Caratterizzazione ampelografica dei vitigni autoctoni piacentini – Fregoni, Zamboni, Colla (Università Cattolica S.C., 2002)
- Guida ai vitigni d’Italia – Fabio Giavedoni, Maurizio Gily (Slow Food Publisher, 2005, re-print 2010)
- I vini piacentini – Corrado Sforza Fogliani, Serafino Maggi (Chamber of Commerce of Piacenza, 1970)
- Piacenza Terra di Vini – Consorzio tutela vini d.o.c. Colli Piacentini (1996)
- I vini e i produttori dei Colli Piacentini – Stefano Quagliaroli (Wissen, 1995)
- Storia e cultura del vino: fonti inedite e casi esemplari sul vino piacentino dall’antichità a oggi – Stefano Pronti (Tip.Le.Co, 2008)
- Sul nome del Gutturnio – Flaminio Ghizzoni (Gallarati, 1979)
- Gutturnium – Serafino Maggi, reviewed by G. Comolli (Consorzio Tutela della d.o.c. dei vini Colli Piacentini, 1989)