Earth is the wealth of all mankind. Moreover, we are talking not only about the planet, but also about the soil reserves on its surface. Without them, there would not have been such a diverse flora, and heterotrophs (which include any animal and human being) could not have appeared in principle. How did the soil form on the surface of the planet? The soil formation factor is "to blame" for this. More precisely, their whole group.
Main classification
V.V. Dokuchaev believed that five basic factors should be distinguished:
- Maternal breed.
- Climatic parameters. In general, the climate as a factor in soil formation is considered by many scientists from a key position, since its role is really impressive.
- Flora.
- Fauna.
- Terrain and past tense.
But these are not all the main factors of soil formation. Today, scientists believe that two more items need to be added to this list: the effect of water (precipitation) and human activity. And now we will deal with all the factors in more detail, discussing their characteristics. So, the most important factor in soil formation is the substance that gave rise to the soil.
Mother breeds
As you can understand, these are the minerals from which fertile (or not so) soil was once formed and continues to form. It is from the primary rock that the mechanical, physical, chemical and other properties of the soil depend. Thus, soils that were originally formed, for example, from granite and similar rocks, may not be equivalent to those that came from tuff and pumice.
What are the parent breeds? They are magmatic, sedimentary, and metamorphic. By the way, both granite and pumice with tuff are igneous rocks, but the soils from them are different. What does it depend on, because the soil formation factor is the same?
How do soil properties depend on origin?
The chemical and mineralogical composition, which depends not only on the rock, but also on the specific region of its origin, plays a huge role in the properties of the soil layer. So, if a mineral is carbonate, has an alkaline reaction (or is close to neutral), then the soil formed on its basis quickly begins to accumulate humus and acquires high fertility. Thus, the main factors of soil formation are extremely important, since the size of potential crops in the future directly depends on them.
If the breed is acidic, then all these processes go several times slower. In the case when the mineral contains a large amount of water-soluble salts, the soil “turns out” too saline. In addition, the mechanical composition is also of great importance, since heat capacity, moisture capacity and other important indicators depend on it, on which the soil fertility in a given area directly depends.
Relief
This soil formation factor is rarely remembered, but in vain. After all, it is the relief that influences the distribution of solar radiation, precipitation, and other factors over the surface of the rocks, which means that the characteristics of the soil, which ultimately results in “output”, depend on it.
This is most radically manifested in the mountains with the differences in pressure, lightness and radically different temperature regimes existing there. Here, air masses and their convection are of great importance, as a result of which huge volumes of air with different temperatures constantly blow over mountainous slopes. In many respects, the relief, as a factor in soil formation, also depends on the climatic features of the area, since without the combination of these two conditions the soil will not be able to form.
Humidity is also different, and after "transshipment" through mountain ranges it decreases sharply. As a result, the rock erodes to a varying degree, settles, and collapses to form fractions of various sizes.
Perhaps, the most important thing is the effect of lighting and solar radiation, which differs by an order of magnitude in different climatic zones. So, in the Far North zone there are few soils, and they are extremely scarce, and the rocks are preserved in perfect condition. Compare this with desert areas in which rocks have long been crushed to a state of homogeneous quartz sand. If you look at the main factors of soil formation in the Orenburg region, the importance of the relief will be even more obvious.
The so-called syrty, that is, relatively low ridges, play a huge role in that area. In combination with flat terrain, such a relief predetermines high speeds of movement of air masses above the surface of parent rocks, which leads to their relatively rapid weathering and subsequent destruction.
Under these conditions, the rate of accumulation of humus (and the very presence of organic substances) varies dramatically, as the fraction and chemical composition of the resulting soil differ. Accordingly, it will have a different degree of fertility.
Soil types depending on the differences in relief
At present, it is believed that as a result of natural processes, three types of soils can be formed, which are also called “moisture horizons”:
- Automorphic varieties. Their formation occurs in conditions of free runoff of surface water and deep occurrence of soil moisture. In this case, the prevailing role begins to play the biological factor of soil formation.
- Hemihydromorphic. The formation of such soils occurs when surface moisture can stagnate for some time on the surface of parent rocks, and soil sources occur at a depth of not more than six meters.
- Hydromorphic soils. Accordingly, such a soil is formed in cases where surface water can stagnate on the surface of the rock for a long time, and soil moisture lies at a depth of not more than three meters.
In all these cases, the
anthropogenic soil formation
factor can also be of considerable importance. A person in the process of his economic activity often drains or floods large areas of the earth's surface, which greatly affects the characteristics of soil formation.
Erosive processes
If the surface slope is 30 degrees or more, then the relief becomes especially important. So, under these conditions, water erosion is widespread. It acts much stronger than the wind variety, which is common in areas with a flat topography or where the surface slope is very slight. If you look at the main factors of soil formation in the Orenburg region, this is easy to see. In those parts, the main role in the “abrasion” of the surface layer of mineral rocks is played by the wind, which can reach extremely high speeds.
The relief plays an important role even in the evolutionary process of the development of flora in a particular area. This is most pronounced when changing the channel of the rivers or the departure of the seas (or vice versa, flooding of areas). This leads to an increase or decrease in the level of soil water, a change in the cycle of soil development (the automorphic type changes to hydromorphic, or vice versa).
Biosphere impact
The biological factor in the formation of each soil is leading. Only after the first living microorganisms appeared on land did it, in principle, develop. In principle, the process of soil formation itself can be considered as a deep interaction between living (microorganisms) and inanimate (destroyed rock) nature. The mother breed itself in the course of this process is pretty transformed. The main condition for ensuring the continuity of soil formation is the influx of radiant solar energy to the surface of the planet.
Atmospheric gases, flora and fauna, products of their livelihoods - all these factors and conditions of soil formation “led” to the fact that today we have under our feet fertile land on which humanity grows food for itself and feed for farm animals.
Once again we repeat that a kind of "energy meter" is the amount of incoming solar energy. On the surface of the planet, it helps the transition of minerals (that is, inanimate nature) into the living. As you probably guessed, we are talking about the process of photosynthesis. In addition, solar energy helps the transition of dead parts of plants back into non-living matter. Due to the continuous process that has taken place over thousands and millions of years, our planet has acquired a unique “soil cover”, which is the key to fertility and reproduction of plant biomass.
What other soil formation factors should be mentioned? An essay written even by a middle school student will inevitably consider flora in the context of its important role in the process of humus accumulation. And that is absolutely true!
The role of plant mass
Plants are the main “supplier" of huge volumes of biomass for the entire soil. In addition, they also accumulate solar energy (9.33 kcal / gram). Since on average up to ten tons of plant organisms grows on one hectare, about 9.33 * 107 kcal of energy is accumulated on this area. Such a huge amount of it not only plays an important role in all processes of soil formation, but can also be successfully used by humans. So not only plants are soil formation factors, but also a valuable energy resource! An ideal example is coal, the incredible reserves of which man began to use intensively in the 19th century.
Autotrophs extract from the mother rock all the minerals they need, and then transfer it to the most complex organic compounds, from which humus is subsequently obtained. In part, these compounds again come back when they are washed out of dead plant debris by water. These most important factors and soil formation processes contribute, inter alia, to uniform mixing of the remaining parent rock and organic matter.
Places of concentration of plant biomass
It is natural that in forests the concentration of the largest amount of biomass of plant origin occurs. But this is not a completely accurate impression, since its really huge growth occurs only in the steppe zone, where at least 85% of all the accumulated organics returns to the soil again. That is why the latter in the steppes is much more fertile than in the forests, where the soil characteristics in this regard are not too "outstanding". That is, the factors of soil formation, in short, vary significantly, even though they are similar in appearance.
Why is this happening? The fact is that in forests from the soil layer with a low humus content, many mineral and organic substances are simply washed out under the influence of atmospheric moisture. In grassy biocenoses, the remains of plants are densely compacted, forming massive soil horizons. The same conditions contribute to the formation of peat, as there is a lot of moisture and little oxygen on the lower tiers, which could stimulate decomposition processes. What other characteristics of soil formation factors exist?
Ash content
In many ways, the process of decomposition of plant residues depends on the chemical composition of the latter. So, the ash content of needles (that is, the amount of the remaining mineral part) is no more than 1-2%, and in deciduous forests this indicator increases to 4%. In the steppes, the degree of ash content of plant residues can immediately reach 5-6%, and in salt marshes this indicator generally increases to 14%! True, in the latter case, it does not have much significance, since 90% of the mineral part is the same sodium, calcium, and potassium chloride, which are found in many in the salt marshes themselves.
Plants are characterized in that they take exactly the amount of salts and compounds that they really need for growth and development from soils with different mineral composition. For example, in cereals and diatoms, the concentration of those elements that are mainly characteristic only of silicas is very high. In the soil of this particular region, the concentration of these compounds may be negligible. Desert plants are the most striking example of this statement, since they contain a huge amount of mineral salts.
Why do they need these compounds? Everything is simple - sand, in which these autotrophs grow, is extremely scarce on the content of all the elements necessary for plants, which have to be stored inside your own organism.
The role of the animal world
But if in a school or other educational institution you are asked a question: “What are the factors of soil formation”, do not forget to mention the large role of the fauna. Animals in the formation of fertile soil also play an important role. And here, the fact that the soil itself is home to many thousands of species of a wide variety of animals and microorganisms plays a significant role. They have a “duty” to grind and process the plant mass and its subsequent mixing with the underlying soil horizons.
Mammals and all other vertebrates create their burrows and nests in the thickness of the earth. Moles, mole rats, ground squirrels and other burrowing creatures carry the lower parts of the rock up. It is in those areas where these animals are many (steppes) that there are saturated chernozems. Earthworms and larvae also carry out a large amount of work to convert the organic component of the soil into humus. In addition, invertebrates mix organics and inorganics. Like all natural factors of soil formation, they contribute to the acceleration of the accumulation of organic substances.
Of course, the prevalence of the animal world and its diversity are entirely dependent on both geographical and climatic factors. The more diverse the flora and fauna, the better and “better” the soil is obtained at the exit, the more organic matter in it and the higher the fertility.
Climatic factors
Finally, we consider climate as a factor in soil formation. A lot depends on geographic and climatic conditions: just look at Kazakhstan and the Gobi desert. The total amount of radiant energy entering the earth’s surface also depends on the location. Accordingly, it is maximum at the equator, minimum - at the pole. Both circumstances negatively affect the processes of soil formation. So how is the soil formed? Soil formation factors also strongly depend on the weather.
In many ways, weather and climate depend on the height of the area above sea level. It should be understood that there are two forms of climate: macro and micro. The wind and various types of precipitation take the greatest part in soil formation. The more diverse the climate, the more “motley” is the soil at the exit. One way or another, but the thermal regime plays a significant role in the heat capacity of the soil. This is especially noticeable in mountain conditions, with a different slope of the surfaces.