The Somma-Vesuvius volcanic complex is characterized by the presence of soils with different degrees of evolution and differentiation.
The southern part of the complex, including the edifice of Vesuvius, represents the area of most recent formation and pedogenesis.
The current cone of Vesuvius, between 850 and 1200 metres above sea level, mainly includes low-vegetation areas, where lava and pyroclastic sediments (ashes and lapilli from 1944) emerge.
The soils are little or completely undeveloped and are formed by recent ash and lapilli deposits colonized by pioneer vegetation (broom bush) and rocks by lichens. The rocks are colonized by lichens.
The high slopes of Vesuvius, between 350 and 800 m a.s.l., are often very steep and inclined. Here the natural vegetation consists of broom shrub, holm oak woods and large areas with reforestation in Pinus pinea.
The soils have depths varying from 20 to 100 cm and are generally very young, with little evolved surface horizons and rich in organic matter humified.
They develop from pyroclastic-falldeposits and are found mainly in the presence of holm oak forests, while pine forests generally cover the lava substrate.
The soils have a moderately coarse texture and a moderately acidic reaction. They are classified as Vitric Andosols (IUSS Working Group WRB, 2015).
The lower slopes of Vesuvius, below 350 m a.s.l., are generally moderately to slightly inclined and with frequent anthropogenic terraces. The vegetable gardens and horticultural and floricultural open field
cultivations constitute the main agricultural use. The soils may be deep to very deep, but not very pedogenized because they develop from recent pyroclastic and volcanoclastic deposits.
The soils have a moderately coarse texture, are not calcareous. Reaction: from moderately acidic to neutral. They are classified as Humic Vitrixerands franc sandy scoriaceous (USDA, 1975) and Vitri-Mollic Andosols (FAO, 2015).
The northern part of the complex, consisting of the remains of the slope of Monte Somma, is the oldest area in which the pedogenesis is generally more advanced.
The soils have a moderately coarse texture and a moderately acidic reaction. They are classified as Andi-Eutric Cambisols (IUSS Working Group WRB, 2015).
On the slopes of the medium-low altimetric range, below about 700 m a.s.l., the soils are moderately deep (over 150 cm). Below the forest, there are a litter of poorly humified organic material (Oi), an
organomineral horizon (A), a series of altered mineral horizons (Bw1, Bw2) and pyroclastic deposits that are little (BC) and not at all altered (C).
A/C is an organo-mineral horizon (A) comprising inclusions of pyroclastic deposits that have been slightly or not at all altered (C).
Often in the pedological profile it is possible to identify the overlapping of soils that have developed in different periods of time and therefore also very ancient soils. In this case it is said that the soil has formed in several pedogenetic cycles.
Avellino Pumice eruption, dated about 3950 years ago.
This soil, buried by the eruption of the Avellino Pumices, dates back to the Early Bronze Age, and is therefore over 4000 years old.