it is understood by pedogenesis(I ask: soil + genesis: origin) the process of origin or formation of the soils. It is a slow process that takes hundreds or even thousands of years to complete, depending almost entirely on external factors such as climate, water and even winds.
Pedogenesis is operationalized from the transformation of rocks, which, for this reason, are called “mother rocks”, since their characteristics will also define the chemical and mineral characteristics of the soils from them. It is clear that these soils undergo transformations other than those arising from factors related to living beings and other elements, gaining new contours and specific characteristics.
The main process responsible for the formation of soils is the weathering. Without this phenomenon, it would not be possible to talk about the origin processes of different types of soils. Weathering is nothing more than the wear of the rock with its disaggregation into particles (physical weathering) or the its decomposition (chemical weathering), which may also occur from the action of living beings (weathering biological).
After this disaggregation or decomposition of the rocks into particles, which are called sediments, we have the activity performed by living organisms, which operate processes of a physical-chemical order, such as the growth of lichens that release substances that give new types of organic composition. The presence of vegetation, in general, is also important, in addition to the action of live microorganisms that decompose the organic remains and form humus, responsible for making the soil more fertile.
See below a simplified scheme of the stages of pedogenesis:
Simplified soil formation scheme
In many respects, the soil is considered a living organism, as it provides the foundation for sustaining life, in addition to being constantly changing. It is a product of the interaction between the atmosphere, the lithosphere and the biosphere, becoming a constitutive part of all these structures that make up the Earth system.
The oldest soils formed during the Tertiary period, about five million years ago or even before that. However, most of the soils originated in the most recent period, in the Quartenary, with ages less than 1.5 million years old.
By Me. Rofolfo Alves Pena
