Soil is the surface layer of the earth's crust in which many organisms live and vegetation grows. It is a structure of vital importance for the development of life. The soil supports the plants and provides them with the necessary nutrients for underdevelopment.
The soil is formed by the decomposition of rocks due to sudden changes in temperature and the action of humidity, air and living beings. The process by which rock fragments get smaller and smaller, dissolve or go to form new compounds, is known as weathering.
The rocky products of weathering mix with air, water and organic debris from plants and animals to form soils. This process takes many years, which is why soils are considered non-renewable natural resources.
The main components of the soil are: living and dead organic matter, represented by remains of vegetables, fungi, earthworms, insects and other animals and by humus (dark and pasty material that has formed over centuries on the soil profile); inorganic matter, caused by the weathering process, thus producing some phosphorus, sulfur and nitrogen, which determine that a soil is fertile for a type of crop.
There is also water, its presence is of vital importance, since it keeps in solution the nutrients that will be used by the plants; and the air, which occupies the pores that the water leaves free, contains atmospheric gases, mostly carbon dioxide. According to their physical state, the components of the soil are in: solid, liquid or gaseous phase.
Among the physical properties of soils are texture, structure, porosity, temperature, consistency and color. Its chemical properties are manifested in the transformation of soil-forming substances; for example, in the presence of organic and inorganic nutrients, ion exchange, and soil acidity (pH).
There are several classifications of soils, which depend on the criteria used to make them; the petrographic, which takes into account the prevalence of one of the members of the mineral fraction thereof where are siliceous soils, clay, limestone, salt, etc. The genetics, who take into account the process that gave rise to them, are the autochthonous and the non-native. And finally, the climatic ones, where each of them corresponds to a climatic zone of the Earth, for example, soil in the intertropical zone.
On the other hand, the word soil refers to the extension of territory that belongs to a state or country. For example; one of my goals in this life is to step on foreign soil.
