Soil Layers (Meaning and Explanation)

We explain what they are and what the different layers of the soil are. Also, what types of soils exist and what soil erosion is.

What are soil layers?

Soil is the surface layer of the Earth's crust. Beneath it are several layers, which differ from each other in their appearance, texture and the materials that make them up.

The soil is made up of three layers:

Lower It is made up of rocks.
Intermediate It is made up of water, clay, stones and sand.
Superior It is made up of mulch (made up of sand, minerals, dead plants and animals), air and water.

Soil science is the science that is responsible for the study of soil and its relationship with plants.

What is soil?

The ground It is the layer that covers the surface of planet Earth. The life of plants and animals develops there.

It is composed of remains of living beings, sand, minerals, salts, rocks, water, air, plants and small animals. Organisms that die on the ground are decomposed by microorganisms, which convert them into organic matter and integrate them into the soil itself.

The soil is a very thin layer that It was formed over the centuries, from rocks that disintegrated due to friction with water, winds and temperatures. It is a non-renewable resource due to the long periods it requires for its formation.

Soil strata

soil layers strata — In addition to the main layers, the soil can have up to six strata or horizons.

In addition to the three layers already mentioned, five horizons that make up the soil are more specifically identified:

Horizon 0 It is the top layer of soil. It is made up of organic matter released from plants, such as leaves and branches. Insects and animals live there.
Horizon A. It is the most fertile layer. Dark in color, it is made up of decomposed organs or humus and minerals.
Horizon B Its color is lighter, and metal hydroxides, clay, salts and oxides dragged from the A horizon are deposited in it.
Horizon C Here there are no deposits of materials nor is there removal, nor does organic matter accumulate.
Horizon D. It is the deepest layer of the soil and the one from which it originates. It is composed of rocks that were not altered.
Horizon E. This layer is found on some occasions. It has little luminous development and is light in color.

Soil types

soil layers calcareous types — The limestone soil is not suitable for agriculture.

Different types of soil can be identified, according to their characteristics:

Limestone They are composed of minerals such as clay, hematite, calcium and magnesium carbonate. It is an arid and dry soil, so it is not a good alternative for cultivation.
Sandy They are dry, rough and do not retain water well, so it drains more quickly. Due to their lack of nutrients, they are not suitable for agriculture. They are characterized by retaining temperature and having larger particles than the rest of the soils.
Slimy They are composed of sand and clay. They are dark brown in color and, unlike sandy soils, in these soils the particles are smaller and softer. In addition, they manage to retain nutrients and water for longer. Thanks to its nutrients and humidity, these are fertile soils suitable for cultivation and almost all plant species develop there, except those that need a dry habitat.
Clayey They are composed of fine yellowish grains. Half of them are clay, which makes them retain a lot of water and nutrients. As their porosity is low, they do not aerate but form puddles and can even rot, so they are not a good option for agriculture.
Stony They are characterized by being composed of small stones that make them semi-impermeable, which prevents water from entering and makes agriculture difficult.
Salines They are soils typical of dry areas and do not have good drainage. Its high salt content hinders the growth of plant species.
Humiferous They are good for growing as their decomposed organic material makes them very fertile. Their color is very dark since they absorb a lot of water and have a large percentage of decomposing organisms.
Of peat They are porous and retain moisture even in dry times, making them ideal for growing. Black or very dark brown in color, they manage to protect the roots in times of low temperatures. In addition, thanks to their acidic pH they control soil pests.

Soil erosion

soil erosion It is produced by factors such as wind or the passage of water. Erosion harms soil fertility as it generates a reduction of organic matter and minerals.

There are different types of soil erosion:

Geological erosion It occurs as a result of heat, cold, wind, snow or rain and takes millions of years.
Wind erosion It is a very slow process that occurs as a result of collisions between the terrain and the particles carried by the wind.
Water erosion It occurs as a result of the impact of raindrops on the ground. The more intense the rain, the greater the detachment and dragging of soil masses and particles. In addition, the sea also erodes the coastal reliefs.
Erosion due to anthropogenic action. It occurs as a consequence of the presence of human beings and their activities (technology, for example).
Splash erosion. It is produced in the soil as a result of the impact of raindrops. The impact will vary according to the size and shape of the droplets.