Men have been exploiting the soil, the “skin of the earth”, for thousands of years, without always knowing its diversity and functions. It is widely defined as “the superficial part of the earth’s surface created from a combination of mineral products from the continental disintegration of rocks and organic molecules from the decomposition of living matter (microbial, vegetal and animal)”. If its traditional dimension as physical support and reservoir of water and mineral elements can be perceived intuitively, its microbiological diversity and its role in the cycles of water and matter are still often unrecognised, notably in strategies of cultivation.
Soil-related factors limiting agricultural productivity have been mastered with the use of enrichment, fertilisation, mechanisation or land improvement (drainage, irrigation). But this success of modern techniques has its own limits; soil compression and erosion, the reduction in biological activity and the transfer of pollutants are some of the new preoccupations of agronomists.
The soil constitutes a heritage that needs protection, and this was recognised by the council of europe in the european soil charter (resolution 72/19 of 26 may 1972), which specifies that “soil is one of humanity’s most precious assets. It enables plants, animals and humans to live on the surface of the earth”.