Soil is a unique natural formation characterized by fertility. Quite often, as a synonym for this word, "earth" is used. How did the soil form on our planet and what factors influenced this process?
What is soil?
This is the upper layer of land on the globe. Soil formation occurred under the influence of several factors on the rocks . It has its own unique composition, structure and properties.
This is one of the most important components of the biosphere and biocenoses on Earth, since it maintains the ecological connections of absolutely all living things with the solid, liquid, and gaseous shells of the planet.
Dokuchaev, who studied in detail the question of how the soil was formed, called it “reflection of the landscape,” because the main features of a particular region are expressed through it. Soil cover is simultaneously decisive for plant communities, but at the same time it depends on them.
Soil properties
The most important property of soil cover is fertility, expressed in its ability to ensure the development and growth of plants.
Physical properties include:
- mechanical composition (density and size of soil particles);
- moisture capacity (the ability to absorb and retain water);
- microbial composition;
- acidity.
Soil Formation Factors
The course of the process of soil formation directly depends on the natural conditions or factors in which it occurs. It is also necessary to take into account their combinations, since they determine the direction of the whole process.
Soil formation conditions are divided into five types:
- parent rock;
- plant communities;
- the activity of animals and microorganisms;
- climatic conditions;
- relief;
- soil cover age.
At present, two more factors are also separately singled out - the effects of water and humans. In the question of how the soil was formed, the leading factor is biological.
Parent rocks
Absolutely the entire soil cover of our planet began to form on the basis of rocks. The determining factor is their chemical composition, since the soil cover incorporates part of the parent rocks. The nature and orientation of the process is influenced by the properties of rocks, such as density, porosity, ability to conduct heat, and the size of microparticles.
Climate
The influence of climate on the process of soil formation is very diverse. The main factors affecting climate are precipitation and temperature conditions. The conditions for the process are the amount of heat, humidity, as well as their circulation and distribution in space. The climatic factor also manifests itself in the process of weathering. The climate also has an indirect effect, since it determines the existence of certain types of plant communities.
Plants and animals
Plants penetrate the parent rock with their root systems and deliver valuable minerals to the surface, which are subsequently converted into organic compounds.
How is humus formed in the soil? Dead parts of plants saturated with ash substances remain in the upper horizons. Due to the constant synthesis and decay of organic matter on the surface, the soil cover becomes fertile.
Plant communities change the microclimate of the area. For example, in the forests in the summer it is quite cool, humidity is increased, the wind strength is minimal, unlike meadows.
A large number of living organisms live in the upper fertile layer of the Earth. In the process of their life, plants and their organic residues decompose. Subsequently, animal waste products are again absorbed by plants.
The totality of plant and animal communities in certain territories affects the formation of soil type. For example, chernozems are formed only under the meadow-steppe type of vegetation.
Relief
This factor has an indirect effect on the process of soil formation. The relief defines the law of redistribution of moisture and heat. Depending on the height, the temperature regime changes. Vertical zonation in the mountainous regions of the planet is associated with altitude.
The nature of the relief determines the degree of climate impact on soil formation. Redistribution of precipitation occurs due to elevations. In the lowlands, moisture accumulates, but on the slopes and elevations it does not linger. The southern slopes in the northern hemisphere receive more heat than the northern ones.
Soil age
Soil is a natural body that is constantly evolving. The way we see the soil cover now is only one of the stages of its continuous development. Even if soil-forming processes do not change in the future, the upper fertile layer may undergo radical transformations.
There are two types of age - relative and absolute. Absolute age is the time that has elapsed since the formation of soil cover to the present stage of its development. However, not all parts of the land were the whole of its historical development. Relative age - the difference in the development of the upper fertile layer within the same territory.
Age can be different - from hundreds to thousands of years.
How was the soil formed?
This question has been of interest to several generations of scientists and researchers. Consider below the generally accepted version of the history of the soil-forming process.
The earth has a solid hot core, which is surrounded by a hot mantle with a viscous structure. Above is the outer crust, which includes rocks.
Four billion years ago, the Earth began to cool. In some places, magma came to the surface and formed basalts, and where it remained beneath it, granites formed. The primary maternal breed changed under the influence of external factors, the synthesis of new mineral substances gradually took place.
After oxygen appeared in the atmosphere, a sedimentary layer began to form. Gradually, as a result of the weathering process, the parent rock became more loose and saturated with oxygen. Thus, clays, sands, gypsum and limestone arose.
It is generally accepted that life has existed on the planet for more than three billion years. According to recent studies, bacteria and protozoa were already living on Earth at this time. The first living organisms easily adapted to new environmental factors and were omnivorous. In the process of life, they isolated some enzymes that dissolved rocks and multiplied quite quickly. Gradually formed soil was inhabited by mosses, lichens, and then plants and animals. As a result of such a settlement, humus formed.
Soil cover is very important for humans. It needs to be studied for the development of agriculture and forestry, as well as for engineering and construction surveys. Knowledge of the properties of the upper fertile layer of the earth is used to solve the problems of geological exploration and mining of mineral resources, health care, and ecology.