What are the classifications of soils and what are the three categories of soils

Soils can be classified into sandy, clay, and loam according to their texture. Particles with a diameter of millimeters account for 50% of the soil particles, and 90% of the soil is called sandy soil. The sandy soil has good aeration and water permeability, low tillage resistance, rapid soil temperature change, poor water and fertilizer retention ability, and is prone to drought.

Soil containing more than 80% particles less than millimeters in diameter is called clay. The clay soil has poor aeration and water permeability, dense soil structure, and great tillage resistance, but it has strong water and fertilizer retention ability, slow fertilizer supply, and long-lasting and stable fertilizer efficiency. Loam is the best soil quality because it is sandy and clay.

Loam soil is loose, easy to cultivate, good water permeability, and has a strong ability to retain water and fertilizer, suitable for planting a variety of Chinese herbal medicines, especially the roots and rhizomes of Chinese herbal medicines are the most suitable for cultivation in loam.

Soils can be divided into three categories: sandy soil, clay soil, and loam.

The type of soil.

Sandy soil: high sand content, rough particles, fast water seepage, poor water retention performance, and good aeration performance.

Clayey soil: low sand content, fine particles, slow water seepage rate, good water retention performance, poor aeration performance.

Loam: the sand content is average, the particles are average, the water seepage rate is average, the water retention performance is average, and the aeration performance is average.

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.

Soil can be divided into three types: sandy soil, clayey soil, and loam.

The main types of soil occurrence in China can be summarized into red soil, brown soil, brown soil, black soil, chestnut lime soil, desert soil, fluvial soil (including sand ginger black soil), irrigation and silt soil, paddy soil, wet soil (meadow, swamp soil), saline-alkali soil, lithologic soil and alpine soil.

Soil is the surface of the earth's land by minerals, organic matter, water, air and organisms composed of fertile, can grow plants of unfixed structural layer, China's soil resources are abundant, various, rare in the world, according to the soil texture classification soil is generally divided into sandy soil, clay soil and loam three categories.

China is rich in soil resources and has a wide variety of types, which are rare in the world. The main soil types in China can be summarized into 12 series, including red soil, brown soil, brown soil, black soil, chestnut lime soil, desert soil, fluvial soil (including sand ginger black soil), irrigation and silt soil, paddy soil, wet soil (meadow, swamp soil), saline-alkali soil, lithologic soil and alpine soil.

Sandy, clayey, loam.

According to the soil texture, the soil is generally divided into three categories: sandy soil, clayey soil, and loam. Properties of sandy soils:

The sand content is large, the particles are coarse, the water seepage speed is fast, the water retention performance is poor, and the aeration performance is good. The properties of clayey soil: low sand content, fine particles, slow water seepage, good water retention performance, poor aeration performance.

The nature of loam: general sand content, general particles, general water seepage rate, general water retention performance, general ventilation performance. Differentiation and assemblage of soil species on the Earth's land surface.

It is closely related to the comprehensive change of physical geographical conditions.

1. The types of soil occurrence in China can be summarized as red soil, brown soil, brown soil, black soil, chestnut lime soil, desert soil, paiqing fluvial soil (including sand ginger black soil), irrigation and silt soil, paddy soil, wet soil (meadow, swamp soil), saline-alkali soil, lithologic soil and alpine soil.

2. Black soil: the east and west sides of the mountains in the central and southern sections of the Daxing'an Mountains, the middle of the Songnen Plain in Northeast China and the watershed areas of the Songhua River and the Liaohe River. Temperate semi-humid continental climate.

The average annual temperature is minus 3 degrees Celsius 3 degrees Celsius, and the annual precipitation is 350,500 mm. The vegetation is temperate grassland and meadow grassland with the highest grass yield. The humus content is the most abundant, the thickness of the humus layer is large, the soil color is mainly black, showing a neutral to slightly alkaline reaction, calcium, magnesium, potassium, sodium and other nutrients are also more, and the soil fertility is high.

3. Brick red soil: Hainan Island, Leizhou Peninsula, Xishuangbanna and the southern part of Taiwan Island, roughly located in the area south of 22 degrees north latitude. Tropical monsoon climate.

The average annual temperature is 23 26 degrees Celsius, and the average annual precipitation is 1600 2000 mm. The vegetation is tropical monsoon forest. The weathering leaching effect is strong, the soluble inorganic nutrients are lost in large quantities, and the iron and aluminum remain in the soil, and the color is red.

The soil layer is deep, the texture is sticky, the fertility is poor, and it is acidic to strongly acidic.

The classification of soils is sandy soils, clayey soils, loams.

1. Sandy soil: high sand content, rough particles, fast water seepage, poor water retention performance, and good aeration performance. It is mainly distributed in the piedmont plains of Xinjiang, Gansu, Ningnianshouxia, Inner Mongolia and Qinghai in northwest China, as well as on both sides of rivers and coastal plains.

2. Clayey soil: soil with few sand particles and clayey soil, water is not easy to pass through it to have good plasticity. It is mainly distributed in semi-humid and humid plains, basin and low hilly areas.

3. Loam: soil with moderate content of clay, silt and sand particles in the composition of soil particles, the texture is between clay and sand, and has the advantages of clay and sand, with good aeration and water permeability, water retention and thermal insulation performance, drought and waterlogging resistance, strong stress resistance, wide adaptability, long tillage period, easy to cultivate into high-yield and stable-yield soil, and is also an ideal agricultural soil.

Factors for the formation of soils

Soil is an independent natural body, which is formed under the very complex interaction of various soil-forming factors, and all kinds of soil-forming factors are equally important and irreplaceable with each other. Organisms play a leading role in it. Soil is formed by the action of living organisms on the parent material of soil formation in a certain period of time, under certain climatic and topographical conditions.

Soils are not born with fertility characteristics to grow green plants. Like biological development, soil development has a series of processes. Among them, parent material, climate, biology, topography and time are the five key soil-forming factors for soil formation.

Refer to the above content: Encyclopedia - Soil.

The current soil classification system in China adopts a seven-level classification system of soil class, subclass, soil type, subclass, soil genus, soil species and subspecies, in which soil type and soil species are the basic taxonomic units.

1. Soil class is the highest unit of the soil classification system, which is the generalization of soil types, and its division highlights the soil-forming process, some commonalities of attributes, and the influence of major environmental factors on soil traits.

2. The subclasses are divided according to the major differences in soil properties formed by the obvious differences in hydrothermal conditions in the same soil class.

3. Soil is the basic taxonomic unit of soil advanced classification, which is divided according to the main soil-forming conditions, soil-forming processes and soil properties of the soil.

4. The subclass is a large difference in the range of reactive soils;

5. Soil is an intermediate taxon that transitions from a high-level taxon to a grass-roots taxon, which has the role of connecting the upper and lower levels.

6. Soil species is the basic unit of grassroots classification in the soil classification system.

7. Subspecies used to be called variants, which were fine chains within the range of soil species, and were variations in certain traits of soil species.