What is soil and rock? What is their significance in nature and how soil differs from rock, read the article.
General information
To identify the differences between soil and rocky soil, you should know the definition of both. Despite the fact that soil formation occurs from rock, there are qualitative differences between them, which make it possible to assume that these are different natural bodies.
What is the difference between soil and rock? According to one concept, it is obvious that soil formation can occur on the seabed, destroyed granite, that is, wherever the rock is in contact with living organisms. According to this concept, it is theoretically possible to distinguish between soil and weathering crust, but in practice difficulties arise.
Soil: basic properties
Soil is a natural body and has certain distinctive properties. The main ones are morphological. The soil differs from the rock in fertility. This is a zone in which roots are distributed and microorganisms live. The soil differs from rocks in the presence of a humus layer enriched with humus, and a combination of horizons.
Soil: Derived Properties
Soil properties, morphological, physical and chemical, are interconnected. The soil differs from the rock in such an indicator as its density. Optimum is one gram per centimeter cubic. If the density is higher than this figure, then it will be difficult for the plant roots to penetrate deep into this layer, and it will remain unpopulated by them.
Soil properties is granulometric and mineralogical composition, structure, composition of horizons. All of them bring together soil and rocky soil in many ways. But the soil differs from the rock in structure, humus horizon and their combination.
Parent rocks
They are called maternal. These are rocks from which soil formation occurs. They differ in origin, composition, structure and properties. All this is transmitted to the soil, which is formed on this rock.
What is the difference between soil and rock? At the initial stage of soil formation, rocks have a huge impact on them. Natural soil fertility depends on the stock of chemical elements in them. For example, soils of the same type, which were formed on different rocks, will vary.
What formed the rocks?
The earth's crust consists of rocks, which are divided into the following groups:
- Igneous, or massive crystalline, rocks are chilled, solidified magma over time. She could freeze at depth or go to the earth's surface. Such rocks have a massive, dense structure. They occupy ninety-five percent of the total mass of rocks, but did not become soil-forming. The exception is rare cases in mountainous areas.
- Metamorphic rocks formed igneous or sedimentary. This is a transition layer. If ancient sedimentary rocks had to be exposed to elevated temperatures and high pressure, then they could be similar to igneous rocks, in which the sedimentary signs did not completely disappear. Such rocks are represented by marble, slates, quartzites, conglomerates. They occupy a considerable part of the earth’s surface, but for soil formation their significance is small. Manifested mainly in mountainous areas.
- Sedimentary rocks are distinguished by the fact that in our era it is on them that the process of soil formation occurs. They accumulated in thicknesses at the bottom of oceanic, marine, river, lake bodies of water and on the plains. The rocks were 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 process of soil formation.
What is rock weathering ?
Soil-forming rocks are formed in close connection with weathering, transfer and deposition of weathering products.
Weathering refers to such processes that result in a change in the qualitative and quantitative indicators of rocks, as well as the minerals of which they are composed. As a result of these processes, the upper layers of the lithosphere change their material composition and turn into a weathering crust.
Weathering Forms
Soil-forming rocks, or, as they are called, parent rocks, are formed under the influence of the weathering process, which is of three types.
Physical is when rocks and their constituent minerals undergo mechanical fragmentation, 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 tremendous destructive power, especially when freezing.
Chemical weathering is impossible without water, oxygen and carbon dioxide. Water is an energy solvent for the minerals that form the rock. Their decomposition occurs faster at elevated temperatures and saturation of the rock with carbon dioxide. What is the difference between soil and rock? The result of chemical weathering is the enrichment of the rock with new minerals and the acquisition of properties such as absorption capacity, cohesion, and others. But the rock does not have the property inherent only in soil - fertility.
Biological weathering is the final stage of 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 minerals for future soil formation.
Soil value
Soils play a huge role in human life. They are studied not only in order to solve agricultural problems. Having knowledge of the properties of soils, it is possible to solve many engineering and construction problems, health problems and mining of useful rocks. It is also impossible to develop forestry, green areas in towns and cities without knowledge of soils.