Studying soil porosity is important for the development of agriculture.
The condition of porous is called porosity : it has pores . A pore, meanwhile, is a very small opening .
Porosity is the property of a material linked to the empty spaces it has on its surface or structure . The concept, which refers to the measurement and size of its holes, appears in multiple areas, such as engineering, metallurgy and pharmacy.
Due to its porosity, a material can be more or less permeable . This is because the pores provide a certain capacity for fluid absorption .
Soil porosity
Soil porosity , in this framework, is very important for the development of agriculture . The soil has microscopic pores and macroscopic pores where water and air stay; Depending on the number of each type of pores, it exhibits different qualities. The liquid phase predominates over the gaseous phase, and its greater variability limits the space occupied by the latter.
A clay soil , for example, has a high number of micropores, having a high capacity to retain water but little aeration. A sandy soil , on the other hand, stands out for its macropores, which favors the passage of water but threatens retention.
The state of the cuticle affects the porosity of the hair.
Calculation of voids by volume
To calculate the porosity of a given soil we must compare the percentage of voids it presents with its total volume ; The formula is 100 x (1 – apparent density / real density ).
This leads us to understand that "total porosity" could not exist, since in that case there would be only pores and, therefore, there would be no soil. The factors on which this property depends are the biological activity, structure and texture of the soil.
Generally, the thickness of the texture elements is directly proportional to the size of the gaps that form between them, although there are two exceptions: they are blocked by colloidal cements or the smallest particles are lodged in them. In any case, these two situations are not very frequent, which is why the relationship between texture and pore size is almost always fulfilled.
Porosity and organic matter
With respect to organic matter, its contribution is notable in increasing porosity; For this reason, colloidal soils are those that exhibit the highest values . The structure has an even greater influence, to the point that in many cases it is enough to know the porosity value of a soil to have an idea of its structure. In fact, porosity is affected by the same agents capable of destroying the structure, such as tamping.
The time comes for biological activity and its influence on soil porosity, a phenomenon that takes place mainly through microfauna. If we observe a soil with a lot of biological activity, we will normally notice many canaliculi next to the worm tracks; These are created by insects and give rise to the concept of tubular porosity .
Hair hydration
Hair porosity , on the other hand, is related to the hair 's ability to absorb and retain moisture. It depends on the state of the cuticle , which is the outer layer of the hair fiber.
These cuticles can be affected by chemical products (shampoos, dyes, etc.) and physical agents (sun rays). Thus, the way in which they manage to maintain hair hydration is modified.
Medium porosity is ideal, since it favors the entry and permanence of hydration. On the other hand, low porosity makes it difficult for hydration to enter , while high porosity makes it impossible to adequately preserve it.