Geography. What is the difference between the soil and the rock?

What is soil and rock? What is their significance in nature and what is the difference between soil and rock, read in the article.

General information

To identify the differences of soil from rocky ground, it is necessary to know the definition of both. Despite the fact that the formation of soil comes from rocks, there are qualitative differences between them, which make it possible to consider that these are different natural bodies.

What is the difference between the soil and the rock? According to one of the concepts, it is obvious that soil formation can occur on the seabed, granite destroyed, that is wherever the rock comes into contact with living organisms. According to this concept, it is theoretically possible to differentiate the soil and the weathering crust, but in practice, difficulties arise.

Soil: basic properties

Soil is a natural body and has certain distinctive properties. The main are morphological. Soil differs from rock formation by fertility. This is the zone in which the roots are distributed and microorganisms live. The soil differs from rocks by the presence of a humus layer enriched with humus and a combination of horizons.

Soil: derived properties

The properties of the soil, morphological, physical and chemical, are interrelated. Soil differs from rock in terms of its density. Optimum is one gram per centimeter cubic. If the density is higher than this figure, it will be difficult for plant roots to penetrate deep into this layer, and it will remain uninhabited.

The properties of the soil are Granulometric and mineralogical composition, structure, addition of horizons. All of them in many respects bring together soil and rocky soil. But the soil differs from the rock by its structure, humus horizon and their combination.

Soil-forming rocks

They are called maternal. These are the rocks from which the formation of soils takes place. They differ in origin, composition, structure and properties. All this is transferred to the soil, which is formed on this rock.

What is the difference between the soil and the rock? At the initial stage of soil formation, rocks have a huge influence on them. The natural fertility of soils depends on the stock of chemical elements. For example, soils of the same type that were formed on different rocks will differ.

What did the rocks form from?

The Earth's crust consists of rocks that are divided into the following groups:

• Magmatic, or massively crystalline, rocks are chilled, with time solidified magma. It could freeze at depth or reach the earth's surface. In such rocks, the structure is massive, dense. They occupy ninety-five percent of the entire mass of rocks, but did not become soil-forming. Exceptions are rare cases in the mountainous areas.
• Metamorphic rocks were formed by magmatic or sedimentary rocks. This is a transition layer. If the ancient sedimentary rocks had to be exposed to high temperatures and high pressure, they could be similar to magmatic rocks, in which the signs of sedimentary rocks did not completely disappear. Such rocks are represented by marble, shales, quartzites, conglomerates. They occupy a considerable part of the earth's surface, but their significance is small for soil formation. They are mainly found in mountainous areas.
• Sedimentary rocks are distinguished by the fact that in our era it is on them that the process of formation of soils occurs. They were accumulated in layers at the bottom of oceanic, marine, river, lake water bodies and on plains. The rocks were exposed to weathering. The products of their deposits, as well as the remains of organisms, are called sedimentary rocks. Among them, carbonate deposits play a major role in the formation of soils.

What is the weathering of rocks?

Soil-forming rocks are formed in close connection with the weathering, transport and deposition of weathering products.

Weathering is called such processes, as a result of which there is a change in the qualitative and quantitative characteristics of rocks, as well as the minerals from which they are composed. As a result of these processes, the upper layers of the lithosphere change their material composition and become the weathering crust.

Forms of weathering

Soil-forming rocks, or, as they are called, maternal rocks, are formed under the influence of the weathering process, which is of three kinds.

The physical is when the rocks and their constituent minerals undergo mechanical disintegration, but their chemical composition does not change. The result of this process is the ability of the rock to pass and retain air with water. The latter has a tremendous destructive force, especially when freezing.

Chemical weathering is impossible without water, oxygen and carbon dioxide. Water is an energy solvent of minerals that form a rock. Their decomposition occurs faster at elevated temperature and saturation of the rock with carbon dioxide. What is the difference between the soil and the rock? The result of chemical weathering is the enrichment of the rock with new minerals and the acquisition of properties such as absorption capacity, connectivity and others. But the rock does not have the property inherent only in soil, fertility.

Biological weathering is the final stage of the preparatory processes for soil formation. How is soil different from rock? The destruction of rocks occurs with the participation of living organisms, which, on the contrary, enrich the soil, creating a new composition. Organisms take from the rocks the necessary mineral substances for the future formation of soils.

Importance of Soils

Soils play a huge role in human life. They are studied not only to solve agricultural problems. Possessing knowledge about the properties of soils, it is possible to solve many engineering and construction tasks, problems of public health and mining of useful rocks. To develop forestry, green zones in towns and cities, too, is impossible without knowledge of soils.