EXCERCISES 4 Match the words to the correct definition. Subsoil Ground Profile Leaching Top soil Weathered 1. 2. 3. 4. 5. 6. ☐ Layer of soil immediately below the surface. ☐ A vertical section of soil showing the sequence of the various layers. ☐ The upper portion of a soil, dark coloured and rich in organic material. ☐ Eroded or altered by the action of water, wind, frost, heat, etc. ☐ Process of removal of soluble constituents. ☐ The solid surface of the earth. a. b. c. d. e. f. 5 Find the questions to these statements. ................................................................................................................................. A section of soil is made up of different colours, chemical compositions and size of material. ................................................................................................................................ We can evaluate the fertility of soil by examining its profile: the soil is infertile if it contains a lightcoloured layer in the subsurface soil from which nutrients have been removed; it is fertile when it has a deep surface layer containing a high quantity of organic matter ................................................................................................................................ Soil formation is affected by a range of geological, chemical and biological processes that occur over long periods of time. ................................................................................................................................. A soil profile is usually made up of six layers. ................................................................................................................................ There are four basic types of soil: sand, silt, clay and loam. ................................................................................................................................. It is dark and very fertile, and consists of minerals and a large amount of organic matter. ................................................................................................................................. It is composed of mineral materials leached from the upper layers, but is not very rich in humus. ................................................................................................................................. This layer is mostly unaffected by atmospheric agents and is at the base of a soil profile. 1. 2. 3. 4. 5. 6. 7. 8. 6 Complete the table. Loam, silt, clay, sand GLOSSARY clay: argilla eluviated: eluviale floodplain: pianura alluvionale layer: strato del terreno to leach away: percolare leached: lisciviato loam: terreno a medio impasto parent rock: roccia madre silt: limo unweathered: inalterato dal clima to weather: deteriorarsi con l’azione dell’acqua, vento o gelo wetland: palude