The soil as an ecosystem
The atmospheric agents (temperature, rain, wind, ice, etc.) and the action of living beings contribute to the formation of the soil, which will then be sustenance of many species animals and vegetables.
- Inorganic matter: Fragments of rocks and minerals from the alteration of the rock, in addition to the water and air that fill the gaps that remain between these minerals.
- Organic matter: Many living things such as bacteria, fungi, vegetables, worms, ants, etc., and remains of undecomposed organisms and humus (decomposing organic remains).
The process of soil formation begins when a mother rock, located on the earth's surface, is exposed to weathering by the action of geological and climatic agents (water, ice) that alter the rock and decompose it. From then on, some microorganisms such as bacteria, lichens and mosses, taking advantage of the loose rock material remains, implant and colonize the rock. Some of these living things can take root and alter rock. When they die, their organic matter decomposes and affects the rock as well. After these first colonizers other animals will appear andmore complex plants that will make the layer of alteration located on the rock increase. From there, the soil horizons will form.
The soil is divided into different layers called horizons in which the different materials that compose it are arranged:
- Horizon 0 is the upper layer, made up of plant and animal remains. Its color is dark because it has a lot of humus.
- Horizon A (from washing or leaching). Its color is clear because the infiltrated water dissolves the mineral salts and carries them further down.
- Horizon B (of precipitation). In this horizon, the precipitation of the mineral salts washed in the horizon A occurs.
- Horizon C: It has fragments and remains of the bedrock.
- Bedrock. Undisturbed rock, splitting which, when weathered, the soil was generated.