The study of soil formation and composition, the study of soil composition

Soil is a loose, fragmented and porous substance, which is a complex system composed of three parts: solid, liquid and gas. The main components of soil are minerals, organic matter, soil moisture, and soil air.

Minerals are the skeleton of the soil, mainly the products of the weathering of rocks, with particles of different sizes, namely gravel, sand and clay, which make up 95% of the soil composition.

Organic matter mainly comes from animal and plant residues, and is decomposed into humus by the action of soil microorganisms during the decay process. The number of microorganisms in the soil is very large, and it can reach tens to billions in 1 gram of soil. Organic matter in the soil is an important source of plant nutrition, as well as a source of plant carbon, and can promote the formation of soil aggregate structure.

Soil moisture mainly comes from precipitation, irrigation water, and water vapor condensation. Plants grow by absorbing water from the soil, and when the soil has little moisture, the plants do not grow well or wilt.

The composition of soil air is basically the same as that of the atmosphere, and it contains more carbon dioxide. Under the action of certain microorganisms (such as nitrogen-fixing bacteria), nitrogen in the air can be continuously fixed and released for plant absorption. Soil air has an effect on seed germination and root development.

When the soil is well aerated, the decomposition of organic matter is fast, and the disease resistance of crops is enhanced.

By volume, the soil contains about 38 minerals, 12 organic matter, and 50 air and moisture.

Soil is mineral particles of different sizes (sand, soil and gum) formed by the weathering of rocks. There are many types of soil minerals, and the chemical composition is complex, which directly affects the physical and chemical properties of the soil, and is one of the important nutrients of crops.

Solid soil particles composed of minerals and humus are the main body of the soil, accounting for about 50% of the soil volume, and the pores between the solid particles are occupied by gas and water.

The vast majority of soil gas is oxygen and nitrogen entering the atmosphere, and a small part is carbon dioxide and water vapor produced by life activities in the soil. The moisture in the soil enters the soil mainly from the surface and includes many dissolved substances.

There are also various animals, plants, and microorganisms in the soil.

The composition of the soil studied is as follows:

1. Soil is composed of minerals weathered from rocks, organic matter produced by the decomposition of animals and plants, microbial residues, soil organisms (solid phase substances), jujube limbs and water (liquid phase substances), air (gas phase substances), oxidized humus, etc.

2. The substances in the soil can be summarized into three parts: the solid part, the liquid part and the gas part. Solid matter includes soil minerals, organic matter and nutrients obtained by microorganisms through light sterilization.

Liquid matter mainly refers to soil moisture in the stool world. Gases are the air present in the pores of the soil.

3. These three types of substances in the soil constitute a contradictory unity. They are interconnected, mutually restrictive, provide the necessary living conditions for crops, and are the material basis of soil fertility.

Soil refers to a layer of loose material on the earth's surface, composed of various granular minerals, organic matter, water, air, microorganisms, etc., which can grow plants. The soil is composed of minerals weathered from rocks, animals and plants, organic matter produced by the decomposition of microbial residues, soil organisms (solid substances), water (liquid phase substances), air (gas phase substances), and oxidized humus.

Solid matter includes soil minerals, organic matter and nutrients obtained by microorganisms through light sterilization. Liquid matter mainly refers to soil moisture. Gases are the air present in the pores of the soil.

These three types of substances in the soil constitute a contradictory unity. They are interconnected and mutually restrictive, providing the necessary living conditions for crops, and are the material basis of soil fertilizer and rock power.

In general, soil is made up of three types of substances: solid, liquid and gaseous. Soil formation factors are as follows:

1) Parent factors of soil formation.

Weathering breaks the rock, changes the physical and chemical properties, and forms a loosely weathered crust, the upper part of which can be called the soil parent material. If the weathered crust remains in place and forms a residue, it is called residual parent material.

2) Climatic factors for soil formation.

The influence of climate on soil formation is manifested in two aspects: direct and indirect effects. Direct impact refers to the effects on the water and thermal status 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.

and 3) biological factors of soil formation.

Biomacaria is the most active factor in soil organic matter and soil formation.

4) Topographic factors of soil formation.

The influence of topography on soil formation is mainly indirectly caused by the redistribution of matter and energy. In mountainous areas, different climate and vegetation zones are formed due to the vertical changes of temperature, precipitation and humidity with the increase of terrain, resulting in significant vertical zone differentiation of soil composition and physical and chemical properties.

5) The temporal factor of soil formation.

Among the above-mentioned soil-forming factors, parent material and topography are relatively stable influencing factors, while climate and biology are more active influencing factors, and their roles in soil formation are constantly changing with the evolution of time. Therefore, soil is a natural entity that undergoes constant change, and the process of its formation is quite slow.

6) Human factors in soil formation.

In addition to the five natural soil-forming factors, the influence of human production activities on soil formation cannot be ignored, which is mainly manifested in the formation and evolution of soil by changing soil-forming factors.