General characteristics of recent Vesuvian soils
The soils of Vesuvius are young and not very developed, with chemical and physical characteristics strictly connected to the eruptive history of Vesuvius. Following sedimentation, volcanic materials are altered over time by the combined action of atmospheric agents and living organisms. The position of volcanic deposits in the landscape ( for example on the steep high slopes of the volcano or in the piedmont areas) influences the pedogenetic processes in progress and the formation of pedological horizons. In fact, surface runoff water tends to erode and remove more soil particles along the slopes, reducing the thickness of the most superficial soil horizons (O and A) and sometimes even the deepest (B), when real landslide phenomena are triggered. The cyclical eruptive activity of the volcano has brought, over time, to the progressive overlapping of volcanic deposits on soils already in evolution, stopping from time to time the process of formation (pedogenesis), which is then resumed on the subsequent and more recent volcanic deposits in contact with the atmosphere. This cycle has created complex pedological profiles, formed by the alternation of buried soils and volcanic deposits.
Pedological horizons
O – organic horizon
A – organo-mineral horizon
B – mineral horizon
C – little or no altered horizon
of pyroclastic materials
R – lava rock
Suffixes
p – worked horizon
i – little decomposed organic materials
e – moderately decomposed organic materials
w – altered horizon
VESUVIAN AREA AND LOCATION OF THE SAMPLED SECTORS
Sampled sites
Recent soils have been sampled in order to preserve their internal structure by slowly inserting special plexiglass containers into the soil. Sampling only concerned the superficial portion (the first 40 cm) of the soils and was carried out at 4 sites in the Vesuvian area, in order to show the different characteristics.
The sampled sites are:
1. Boscotrecase, vineyard of Matrone estate;
2. Boscotrecase, pinewood of locality Fruscio – Ciaramelle;
3. Herculaneum, Vesuvian Observatory garden, mixed forest;
4. Nola, archaeological excavation of Via Antica Muraglia, agricultural land.
SITE 1
Locality: Boscotrecase, Matrone estate
Land use: vineyard
Altitude: 215 m a.s.l.
Substrate: pyroclastic materials (scoriaceous lapilli) from the Vesuvian eruption of 1906.
Soils: organo-mineral horizons (Ap and Bw) not very altered, they have been altered as a result of the activity of planting the vineyard
SITE 2
Location: Boscotrecase, Ruscio – Ciaramelle
Land use: pine forest
Altitude: 220 m a.s.l.
Substrate: lava flows from the 1906 Vesuvian eruption
Soils: organic horizons (O – litter) slightly (Oi) or moderately (Oe) decomposed horizons superimposed on slag (C) and lava rock (R1 and R2)
SITE 3
Location: Herculaneum, garden of the Vesuvius Observatory
Land use: mixed forest (Holm-oak, Mediterranean scrub)
Altitude: 600 m a.s.l.
Substrate: pyroclastic materials (ashes) from the Vesuvian eruption of 1906
Soils: organo-mineral horizons (A and Bw) formed by the alteration of volcanic ash in the presence of organic matter deriving from the foliar residues of the forest
SITE 4
Locality: Locality: Nola, archaeological excavation, Via Antica Muraglia
Use of land: wooded vegetable gardens
Altitude: 38 m a.s.l.
Substrate: ash and lapilli from the 1944 and 1906 eruptions, on a dense sequence of deposits
from older Vesuvian eruptions
Soils: organo-mineral horizons (Ap and BC) slightly altered; they are worked as a result of agricultural activities
