Soil composition
The soil consists of a mixture of solid particles, water and air. Solid particles can be inorganic or organic. The inorganic parts are mainly minerals: silicates, oxides and hydroxides of iron, aluminium, manganese, etc. that, according to their dimension, are classified in skeleton and fine earth, which are then divided into sand, slime and clay. These derive from the alteration of rocks into smaller and incoherent material, which accumulates to form superficial deposits. The deposit of incoherent material can occur in the same place as the rock was disintegrated.
The degradation processes of vegetal residues (leaves, fruits, dry branches or whole plants) and dead animals lead to the creation of organic fractions of the soil. Organic compounds can keep unaltered for long periods (non-humic compounds) or be subject to deep and fast changes in their original chemical structure (humic compounds or humus).
Water and air occupy the free spaces between solid particles (pores), and form a thick and extended network that allows water to move in the ground.
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From the Multimedia section
Facts
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Laterite and bauxite deposits
These deposits can be observed in those tropical areas that are characterized by...
And in underground tunnels?
There are groups of terrestrial animals that eat insects, worms and other invertebrates...
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The most populated cities in the world
In the last 50 years the world population has passed from 2.5 billion to 6 billion...
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Mountains on the Earth
The different landscapes that we analysed in the previous section are distributed...
Soil erosion
Just like water, air and other natural elements, the soil may be considered a resource; it is, however, a non-renewable…
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24 February 2011
Laterite and bauxite deposits
These deposits can be observed in those tropical areas that are characterized by...
And in underground tunnels?
There are groups of terrestrial animals that eat insects, worms and other invertebrates...
-
What about the permafrost?
In Sub Arctic Swedish regions, some scientists studied the changes of permafrost...
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The most populated cities in the world
In the last 50 years the world population has passed from 2.5 billion to 6 billion...
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24 February 2011
Laterite and bauxite deposits
These deposits can be observed in those tropical areas that are characterized by...
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And in underground tunnels?
There are groups of terrestrial animals that eat insects, worms and other invertebrates...
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What about the permafrost?
In Sub Arctic Swedish regions, some scientists studied the changes of permafrost...