The role of various soil forming factors in soil formation

The parent material is the surface layer of the weathered crust, which refers to a layer of loose and youngest geological mineral layer formed on the surface of the primary substrate through weathering, transportation, accumulation and other processes, which is the material basis for the formation of soil and the predecessor of soil.

1.The parent material influences the speed, nature and direction of the soil-forming process; 2.The parent material affects the physical properties of the soil, and the nutrients and texture of the soil formed on different parent materials are different; 3.The parent material affects the mineral composition and mechanical composition of the soil.

Organisms introduce a large amount of solar energy into the soil, so that the nutrients scattered in the lithosphere, hydrosphere and atmosphere are enriched to the soil surface, forming a soil humus layer, making the soil have fertility characteristics, and promoting soil formation and evolution. So, in a certain sense, without the role of living things, there is no process of soil formation. 1.

The role of plants.

Plants use solar radiation energy to synthesize organic matter, selectively absorb and enrich nutrients scattered in the parent material, water and atmosphere, form a biological cycle, and promote the occurrence and development of soil fertility.

2.The role of animals.

Soil fauna is not only one of the important soil organic matter, but also directly involved in the formation of soil humus and the transformation of nutrients. Animal activity loosens the soil, promotes the formation of structures, and improves soil nutrient status.

3.The role of microorganisms.

Decomposition of plant residues promotes mineralization and release of nutrients; synthetic soil humus; Accelerate the transformation of inorganic matter, fix nitrogen in the atmosphere, and increase soil nitrogen content.

First, biological factors:

The organisms in the biological factors include plant microorganisms and animals, biological factors are the most active factors that promote soil genesis, plants absorb nutrients in the parent material, water in the water body and carbon dioxide in the air, thus forming organic matter, plus the residue of microorganisms, the residue of animals, can be decomposed and released by microorganisms. Thus returning to the soil accelerates soil formation.

Second, climatic factors:

Climatic factors, especially moisture and heat in the air, can directly or indirectly affect the activity of plants or microorganisms, and thus soil formation.

Third, topographical factors:

Crustal movement causes the redistribution of surface materials and energy, so that zonal soils contain non-zonal soils.

Fourth, the parent factor:

The parent material is formed by the weathering of rocks, and then through soil formation, the soil is formed, so the parent material can directly determine the nutrients in the soil, that is, the time of soil formation.

Fifth, the time factor:

The time factor is the intensity factor of soil development, which can affect the parent material factor, biological factor, topographic factor, time factor, and thus affect the formation of soil.

Sixth, the human factor:

Artificial cultivation and soil relocation, or other activities can accelerate soil formation.

The main factors influencing soil formation are climate, biology, topography, parent material and time.

1. Climatic factors: direct impact - the influence on the water and heat conditions of the soil and the nature and intensity of physical and chemical processes in the soil through the frequent exchange of water and heat between the soil and the atmosphere.

Biological factors: Organisms are the most active factors in the process of soil organic matter and soil formation, and the essential characteristics of soil - hail residue - the production of fertility is closely related to the role of organisms. Biological processes are realized through the life activities of organisms, in which the formation and maintenance of the food chain is crucial.

2. Time factor: Soil is a natural entity that undergoes constant change, and the formation process is quite slow. In extreme environments such as extreme heat, extreme cold, drought and flooding, as well as on residual parent material formed on hard rocks, it can take thousands of years for a topogenetic layer to form.

However, the development of soil profile is much faster in the mild environmental conditions and on the loose soil parent material that is conducive to the soil formation process.

3. Human factors: human activities act on the formation and evolution of soil by changing other soil-forming factors, and agricultural production activities are an important way. Change the structure, water retention and aeration of the soil through tillage; Change the moisture and temperature conditions of the soil through irrigation source rolling; Depriving the soil of some of the organic matter that should have been returned to the soil through the harvesting of crops, changing the nutrient cycling of the soil; By applying chemical fertilizers and organic fertilizers to supplement the loss of nutrients, change the nutrient composition, quantity and microbial activity of the soil; Agricultural production activities eventually transform natural soils into various types of cultivated soils.

Soil is an independent natural body, which is formed by the very complex interaction of various soil-forming factors with the soil parent material. It is the result of the long-term joint action of natural factors and human activities, and there are six factors that affect its formation:

1. Parent factors:

weathering.

The parent material formed is the material basis of soil formation and the initial element of plant mineral nutrients (except nitrogen), which plays an important role in the physical properties and chemical composition of soil.

2. Climatic factors:

The direct impact is the influence on the water, thermal condition and the nature and intensity of physical and chemical processes in the soil, such as chemical reactions in the soil for every 10 increase in temperature.

The speed is increased by an average of 1 2 times; Indirect influences affect the formation and development of soils by influencing rock weathering processes and vegetation types, among other things.

3. Biological factors:

Organisms are the most active factors in the formation of soil organic matter and soil, of which plants play the most important role. Green plants absorb nutrient elements to make organic matter, and then return the organic nutrients to the surface in the form of litter and debris; Animals provide organic matter to the soil in the form of excrement, secretions and debris, and promote the transformation of organic debris and change the soil structure through gnawing, carrying and agitation. The main functions of microorganisms in the process of soil formation are the decomposition, transformation and humus of organic residues.

of the synthesis. 4. Topographic factors:

It mainly affects soil formation indirectly by causing the redistribution of matter and energy. Slope and aspect, for example, can also affect soil development by altering water, thermal and vegetation conditions.

5. Time factor:

The role of parent material, topography, climate, and organisms in soil formation has all evolved over time. For example, in extreme environments, it can take thousands of years for the weathering of rocks to form a tomogenetic layer, while it takes 1000 to 1500 years for a typical gray soil to develop.

6. Human activity factors:

The main impact is on the formation and evolution of soil by changing the soil-forming factors. Among them, the impact of changing the condition of surface organisms is the most prominent, such as in agricultural production activities, through the transformation of natural soil into various cultivated soils through hard work.

1. Biological factors include the influence of plants, microorganisms and soil animals on the soil system, and biological factors are the most active factors to promote soil occurrence and development. Plants selectively absorb nutrients from the parent material, atmosphere, and water bodies, and through photosynthesis, produce organic matter, and soil microorganisms decompose organic matter to promote the release of nutrients. Animal carcasses also provide organic matter to the soil, and animals in the soil have special effects on the soil, such as turning and agitation.

2. Climatic factors are the main driving force for the development and change of soil system. It affects the geographical distribution of soil, which is zonal. Climatic factors, especially water and thermal conditions, directly or indirectly affect the activity of plants and microorganisms, affecting the accumulation and decomposition of soil organic matter.

3. Topographic factors generally only cause the redistribution of surface energy and matter, and do not cause new matter. It dominates surface runoff, resulting in non-zonal soils in zonal soil ranges.

4. The parent material factor is the material basis for soil formation. The soil parent material is the product of the weathering of rocks, and the soil is formed by the parent material through the process of soil formation. Different parent materials also have a certain effect on the secondary minerals in the soil.

5. Time factor - degree of development. Soil age is divided into absolute age and relative age. It is an intensity factor for soil development. The four major factors of biology, topography, climate and parent material deepened with the age of soil. Soils evolve over time.

1. Soil formation factors: Soil is the product of climate, parent material, vegetation (biology), topography and time.

2. The role of soil: 1. The role of nutrient bank: soil is an important source of nutrients necessary for terrestrial organisms;

2. Biological support: including mechanical support for green plants, and at the same time, it also has a wide variety and a huge number of biological groups in the soil, which supports underground organisms to live and breed here;

3. Rainwater conservation plays a regulating role in water and solute flow;

4. Nutrient transformation and circulation: realize the circulation and turnover between nutrients and organisms, and maintain the life cycle and reproduction of organisms;

5. Stabilizing and buffering environmental changes: including buffering capacity to changes in external environmental temperature, humidity, acidity and alkalinity, redox properties, filtration, buffering, degradation, fixation and detoxification of organic and inorganic pollutants;

6. Maintain biological activity, diversity, and productivity.

3. Soil formation: Rocks are weathered to form soil parent material (a small amount of minerals are released in the process). Because of the accumulation of organic matter and nutrients, the lower plants settle on the soil parent material to form the original soil (in the process, the organic matter is more abundant and humus is formed).

The formation of the original soil allows the higher plants to form mature soil, which is what we call soil.