What is soil? This word has more than one meaning. Most often it is found in the meaning of "fertile layer." Dictionaries and biological reference books explain the term in more detail.
Soil, according to the scientific definition, is the topmost layer of the earth's lithosphere. Its main characteristics: fertility, heterogeneity, openness, four-phase.
Let's consider each concept separately. Fertility means that the soil is a layer suitable for growing agricultural plants and crops. Formed as a result of the vital activity of a variety of organisms and weathering, the layer is rich in nutrients, and its basis is humus - living organic compounds or their residues that are present in the soil, but absent in living organisms.
What is soil in terms of heterogeneity? This means that the fertile layer is a heterogeneous system, the homogeneous phases of which are separated from each other. Thus, the soil consists of fourphases: solid, liquid, gaseous and microorganisms.
The solid phase includes minerals, organics, various inclusions, i.e. the totality of solids that make up the fertile layer.
Liquid phase - water, which can be in the fertile layer in a free or bound state.
Gaseous consists of gases: oxygen coming from the atmosphere, complex compounds of nitrogen, methane, pure hydrogen. They are formed as a result of fermentation, respiration, decay, etc.
By studying soils, scientists can analyze not only the layer as a whole, but also each of its constituent phases. That is why the full answer to the question of what soil is is so long. In addition, the soil is sometimes considered as a barrier or membrane that simultaneously separates and regulates the interaction of the atmosphere, bio- and hydrosphere.
Answers the question of what soil is in a somewhat different way, GOST 27593-88. It says that the soil is a natural body, independent, organo-mineral, natural-historical, resulting from a combination of factors:
- man-made;
- abiotic;
- biotic.
Soil, continues the definition of GOST, has its own properties (morphological and genetic). It is characterized by certain properties that are responsible for creating conditions for the development of plants, consists of water, air, mineral particles and organic remains.
Type and nature of the soildepend on climate, flora and fauna, origin, microorganisms inhabiting the fertile layer. The task of land use is to preserve and maintain fertility, adequately using the possibilities of the layer.
When used too often, soils are depleted, when overfertilized, they become almost poisonous. In the absence of moisture, soils can become deserted, and with excessive watering, they can turn into ravines. Sometimes soils become s alty or swampy as a result of improper exploitation. These processes have a single name, namely soil degradation.
Restoration of degraded soils is a very laborious, lengthy, not always successful process.
