Soil cover is the biologically active upper shell of the Earth. Its main quality is fertility. It determines its suitability for cultivating cultivated plants, providing food to the world's population. All this gives the soil a major role in agricultural production.
Structure and properties
The soil cover of the Earth is a unique natural formation. For the life of human civilization, its value is high. It is he who is the main food source. It provides the income of almost 98% of the resources for the population. Soil cover is also a place of human activity. It focuses on production - both industrial and agricultural. This is the place where people live.
Soil and soil cover are very diverse. This is due to the fact that the rocks that form them are heterogeneous. Responsible for this is their mineral composition and technological parameters. The ability of the layers of the earth to hold moisture in themselves depends on them. Also, the mineral composition is responsible for the predisposition to soil erosion. This indicator determines the rate of decomposition of organics in it. This gives the soil characteristic features that affect the methods and methods of land use.
The parent rocks, occupying the upper layers of the planet, depending on the intensity of the impact of processes on them - biochemical and biological, created in different areas the soil cover of various productivity and fertility. Human activity also plays a major role in the formation of the upper layer of the Earth.
Soil formation
Natural soil cover was formed from mountain rocks that came to the earth's surface, under the influence of various factors. This is wind, atmospheric moisture, climate change, temperature fluctuations. Initially, their influence led to the fact that the rocks began to crack, turn into the so-called crumb. It began to settle microorganisms that feed on atmospheric nitrogen, carbon, mineral compounds that they extracted from rocks.
The vital activity of microorganisms led to the fact that their secretions gradually destroyed rocks, changing their chemical composition. Subsequently, mosses and lichens began to settle in such places. After the end of their life cycle, microorganisms decompose their residues, forming humus, which is the main organics containing nutrients important for plant life. The vital activity of the latter led to the complete destruction of rocks, starting to turn them into soil.
Growing plants, grass, formed leaf litter, which, decomposing, secreted a significant amount of organic matter. This led to an increase in soil cover.
The soils characterized by the optimal ratio of breathability and moisture capacity include structures formed from rock fragments - fine-grained and fine-grained. In them, the bulk of the fractions has a diameter of 1 to 10 mm. It should also be noted that its parameters and properties depend on the characteristics of the original rock on which the soil was formed.
To obtain a complete picture, specialists carry out selective cuts of land for further study. Their findings are of great importance for the implementation of agricultural activities.
Structure
The soil cover includes a set of macrocells, among which nitrogen, iron, potassium, calcium, sulfur, and phosphorus predominate. Trace elements are also concentrated in it: boron, manganese, molybdenum, zinc. All of them play a role in ensuring the life of plants. By their ratio in the soil, its chemical composition is determined.
The structure of the soil cover is a conglomerate consisting of 4 parts: living, gaseous, liquid, solid.
Hard part
It is the main part of the soil. Its volume is from 80 to 97%. It prevails over the organic component, formed from structures that arose as a result of a long transformation of rocks. The solid part is particles of various sizes, which can include stones of significant size and microscopic particles in thousandths of a millimeter.
It is generally accepted that particles, the main part of which in the soil cover has a size of more than 3 mm, are a rocky component. From 1 to 3 mm - gravel. From 0.5 to 1 mm - sand. From 0.05 mm to 0.001 - dust. Less than 0.001 mm - silt. One that has a particle size of less than 0.0001 mm is colloidal. Soils where particles with a diameter of less than 0.01 mm predominate are classified as clay. Those with fractions ranging from 0.01 mm to 1 mm are sands.
It is the above fractions that determine the main characteristics of the mechanical composition of the soil that carry them to sand, loam, clay.
In small clay fractions, the bulk of the substances necessary for plants is concentrated. Colloidal particles are most valuable, since the trace elements in them are optimally available to plants. As a result, silty clay soil is considered the most fertile.
Particles forming sandy soils contain a significant amount of quartz, which the plants do not provide nutrition.
Liquid part
It is also called soil solution. Represents water in which organic matter and minerals are dissolved. Earth always contains water. However, in different quantities. Its share is from tenths of a percent to 60%. The liquid part ensures the delivery of minerals dissolved in it to plants (roots).
Gaseous part
The gaseous part is soil air. It is located in pores not filled with water. The main component is carbon dioxide. Atmospheric air, there is little oxygen in it. It contains methane, as well as other volatile organic compounds.
Live part
It is represented by microorganisms, which include mycelia, algae, bacteria, representatives of the invertebrate family (mollusks, insects and their larvae, worms, and other protozoa) digging vertebrates. The scope of their habitat is the upper layers of the earth, roots.
Physical properties
The soil cover is characterized by certain physical properties. This is the moisture capacity, water permeability, duty cycle.
Moisture capacity refers to the ability of the soil to absorb and hold a certain amount of moisture. It is determined as a percentage in relation to the soil mass in the dry state. Calculated in millimeters.
Water permeability - the ability of soil cover to pass water. It is determined by the volume of water in millimeters, which penetrates through its upper layer for a specified period of time. This indicator is directly dependent on the type and composition of the soil.
Sandy, structureless, friable has high water permeability. Unstructured, clayey, they pass moisture poorly. As a result, they are predisposed to the accumulation of water in the upper layers. Moisture is poorly absorbed, contributing to the occurrence of water erosion. The upper layers are usually more permeable to the deeper layers.
Duty rate (porosity) - the amount of space that exists between particles of soil cover. It determines the mass of water that the earth can withstand.
Factors affecting the condition of the soil
The characteristics of the soil cover, its composition and properties are constantly subject to changes that occur under the influence of climate and human activity. So, after fertilizers are applied to it, it is saturated with nutrients that favorably affect the growth of plants, thereby changing their physical data.
Improper human exploitation of soil, on the contrary, leads to negative changes, provoking erosion, waterlogging, salinization.
The soil cover improves its characteristics if there is an optimal combination of mineral and organic parts - humus, which is characterized by the retention of moisture with nutrients. Lumpy, aggregated structure increases the level of aeration, implements water infiltration, and increases workability.
Humus is formed due to the fact that organisms consume retreat. At the same time, the mineral parts of the soil cover are mixed with humus, forming a favorable structure.
Fertility
The most important characteristics of soil cover include fertility indicators. It denotes a set of properties that ensure the yield of agricultural cultivated plants.
Natural fertility is determined by the combination of the effects on the soil cover of the regimes (water, air and heat), and the reserves of nutrients in it.
The role of soil in the effectiveness of the Earth’s ecological systems is very large. It provides nutrition to the plants located on its surface, water, stimulating their growth by supplying the necessary chemical elements. It is one of the main components in the implementation of photosynthesis.
The role of man in the conservation of land cover
Mankind is faced with the task of ensuring the correct and efficient use of land, increasing its fertility by providing optimal thermal, air, water regimes. This is achieved, inter alia, by the implementation of land reclamation measures and the introduction of fertilizers into the soil.
Irrational, improper use of land resources leads to the fact that fertility is reduced, the land is depleted. The destruction of the soil begins. Plant productivity is decreasing. The growth of wind and water erosion of the soil is recorded. This leads to the fact that its upper, most valuable layers are carried out through the influence of wind and water on them.
Modern ecologists are sounding the alarm that erosion has already caused irreparable damage to the soil of the planet. It, along with soil pollution by human vital products, has become one of the most dangerous factors threatening the ecology of the Earth.