The soil definition
The soil is the uppermost layer of Earth’s crust. It comprises the alteration products of rocks and
organic remains of living things. The floor can also be defined as the dynamic complex resulting from the interaction between the atmosphere, lithosphere and biosphere.
The factors involved in soil formation are: lithology(rock type that gives the mineral), climate(temperature, humidity, wind), topography (slope and orientation of the slopes), temporal (time of soil formation ) and biological (organisms and remains of living things).
Stages of soil formation
The main stages of the development of a soil are:
– The weathering of bedrock, breaks, resulting in soil mineral components.
– The establishment of living things on the resulting materials in the previous stage. The living activity originates continue altering substances the mineral components. the remains of living plants and animals (carcasses, litter, manure, etc..) lead to the SOM.
The floor consists of inorganic and organic component:
– The inorganic components can be solid (songs, gravel, sand, silt and clay), liquid (water and dissolved salts in water) and gaseous (air in the pores).
– The organic components are microscopic living organisms (bacteria, fungi, etc.), the roots of higher plants andhumus or mulch . The mulch is the set of substances resulting from the activity of microorganisms on litter, the droppings, carcasses of animals, etc.
The soil structure has three main layers or horizons:
– Horizon A or washing : is the uppermost layer, usually dark because it contains humus. The activity of decomposing microorganisms in mineral salts that are carried by rainwater to infiltrate into deeper layers.
– Horizon B or precipitation : is the middle layer, which is deposited in the A horizon of mineral salts that water drag. It is lighter in color than the horizon A.
– Or subsoil Horizon C : is the deepest layer. Material consists of altered bedrock and bedrock itself.