What is the aggregate structure of soil? Why is the aggregate structure of the soil a good structure

Soil aggregate structure is a soil structure in which several soil grains are bonded together to form aggregates.

Because small pores are formed between single grains and macropores are formed between aggregates, the total porosity is larger than that of single grains. Small pores retain water, large pores keep aeration, and the aggregate structure of the soil ensures the good growth of plant roots, which is suitable for crop cultivation. Clumps are polysaccharonic acid glycosides, clay minerals, hydroxides and humus of iron and lead secreted by a variety of microorganisms.

and so on. In short, the soil aggregate structure is based on physical processes such as alternating dry and wet, temperature changes, chemical processes such as chemical decomposition and synthesis, higher plant roots, soil animals and fungi.

and other biological processes and agricultural measures such as human tillage have the greatest impact on the formation of soil aggregate structure.

The role of aggregate structure on soil fertility

It can coordinate the contradiction between moisture and air; ②

It can coordinate the contradiction between the consumption and accumulation of nutrients in soil organic matter;

It can stabilize the soil temperature and regulate the soil thermal conditions; ④

Improved tillage and crop root stretching.

It retains water, and because of the agglomerate, there is air between the soil, so that the roots can breathe, so the agglomerate structure is a good structure of the soil. If there is a lack of air in the compaction.

Soil aggregate structure can coordinate the contradiction between soil moisture and air. It can coordinate the contradiction between the consumption and accumulation of soil nutrients; It can regulate the soil temperature and improve the temperature of the soil; It can improve the arable ability of the soil and improve the growth and elongation conditions of plant roots.

Soil structure is formed by the comprehensive action of physical, chemical and biological factors in the process of soil formation or utilization, and can be divided into three types: block, sheet and columnar according to the shape. According to its size, degree of development and stability, it is further divided into agglomerate, clumpy, blocky, prismatic, columnar and sheet structure.

The aggregate structure is a good soil structure that meets the requirements of agricultural production. The aggregate structure includes aggregates and microaggregates. The aggregate structure refers to the formation of a relatively spherical loose and porous small soil mass under the action of humus and other factors, with a diameter between them, and the diameter is called micro-aggregate.

The number and deterioration of aggregate structure reflect the level of soil fertility to a certain extent.

Expanded the materials of the round exhibition

Characteristics of soil aggregate structure: it has a certain size and character, the diameter is between, and it is spherical; It has a high degree of stability; The pore thickness is reasonable, there are many small pores inside, and there are many large pores between aggregates.

The influencing factors of soil fertility include nutrient factors, physical factors, chemical factors, and biological factors.

Types, characteristics and improvement of soil structure:

Block structure: approximate cube type, length, width, height are roughly equal, smuggling is generally greater than 3cm, 1-3cm within the called nuclear structure, irregular shape, mostly in the clay weight and lack of organic matter in the soil, low degree of ripening of dead loess common this structure, due to mutual support, will increase the pores, resulting in rapid evaporation of water and run moisture, more have the effect of pressing seedlings, not conducive to plant growth and breeding.

Improvement method: raking can be done when the moisture is suitable, after the frozen soil in winter, rolling to improve the content of soil organic matter, can also be mixed with river sand or slag ash to improve.

Sheet structure: arranged in the horizontal plane, the horizontal axis is longer than the vertical axis, and the interface is horizontally sheet-like; The plough layer of farmland, the ash layer of forests, and the compacted soil of gardens all belong to this category. It is not conducive to aeration and water permeability, resulting in soil drought and soil erosion.

Improvement method: loose soil application of organic fertilizer, park street green space pedestrians often pass through, can be carried out breathable pavement, planting ground cover plants or necessary fence protection, crust and compaction can be taken to take the right moisture deep turning, increase the application of organic fertilizer solution.

Columnar structure and prismatic structure: arranged along the vertical axis, the vertical axis is greater than the horizontal axis, the soil is upright, the structure is of different sizes, solid and hard, the internal ineffective pores are dominant, the root system of the plant is difficult to intervene, the aeration is poor, and there are large cracks formed between the structures, which leak both water and fertilizer.

Improvement method: fertilization and planting green manure through deep ploughing.

Aggregate structure: This is the most suitable structure soil type for plant growth, which indicates the level and utilization value of soil fertility to a certain extent. It can reconcile the contradiction between soil moisture and air; It can coordinate the contradiction between the consumption and accumulation of soil nutrients; It can regulate the soil temperature and improve the temperature condition of the soil; It can improve the arable ability of the soil and improve the growth and elongation conditions of plant roots.

The ability of the soil to form aggregates is the structural properties of the soil. Without spatially structured soils, the cultivation function of soils cannot be realized. In terms of soil tillage performance, soil aggregate structure, which is a kind of soil particles cemented into an aggregate structure with a diameter of 1-10 mm, is a soil structure with the best soil tillage performance, which coordinates the soil air permeability and water and fertilizer retention ability.

On long-term cultivated soil, after the aggregate structure of the soil is destroyed, the soil air permeability and the ability to retain water and fertilizer are destroyed, affecting the growth of crops.

The formation of soil aggregate structure requires the following two conditions:One is cemented substance. The metabolites of humus and microorganisms are cemented substances in the soil, and the soil particles (sand and soil particles) are the soil functions under the action of cemented substances to form a porous soil aggregate structure, which has a certain degree of stability, which can realize the functions of water and fertilizer retention and air permeability, and increase the application of fully decomposed organic matter and microbial agents to help restore the aggregate structure.

The second is the force of the outside world. In the process of crop root growth, or soil organic matter in the process of water absorption and water loss, the formation of squeezing effect on the surrounding soil particles, which is an indispensable condition for soil aggregate structure. Deep tillage, fertilization, crop rotation, and grass planting are all conducive to the formation of soil aggregate structure.

Soil aggregate structure is the basis of soil function, and the restoration of soil aggregate structure after damage is a long-term process. Soil is a dispersion composed of solid, liquid and gas phases, and many soil particles are piled up into a porous loose body, that is, the solid skeleton (matrix, base model) of the soil; Water, air, and native organisms all move and live in the pores inside the skeleton; Therefore, the composition of large and small soil particles and the arrangement of soil particles in the solid matrix have an important impact and restriction on soil water, fertilizer, gas, heat and soil organisms.

It is easy to accommodate rainfall, increases the water storage capacity, and the soil is loose and can retain fertilizer; It is formed after the process of single grain, double grain, micro particles, and clumps.

It is conducive to air circulation, which can create good growing conditions for crops and have the ability to retain water; It is formed after many complex reunions.

It plays an extremely important role in promoting the good growth and development of crops. It was formed over a long period of time.

Answer]: Concept: Aggregate structure refers to the spherical loose and porous small soil mass cemented by soil particles. Those with a diameter smaller than are called micro-aggregates.

The formation of aggregate structure can be achieved through two pathways.

The first is multi-level agglomeration, that is, the soil single grain is formed by various rounds of planting to form compound grains (or micro aggregates), and the complex grains are formed by various actions.

Second, the large block of soil disintegrates into aggregates through various forces. In the field, these two pathways are often carried out at the same time, reinforcing each other, and it is difficult to separate them. Waxy.

Multi-stage reunion: including two processes: coagulation and glue blending. a.cohesion; b.Cementation.

Clod disintegration: aalternating wet and dry; b.freeze-thaw alternation; c.biological effects; d.Tillage.

1) It can coordinate the contradiction between water and gas: the soil is loose and porous, which can accommodate more precipitation; The large holes are inflated and the small holes are filled with water.

2) Coordinate the contradiction between organic matter consumption and accumulation, which is conducive to the conservation and release of nutrients.

3) It can stabilize the soil temperature and regulate the soil thermal condition.

4) Improve soil tillage, which is conducive to root extension.

QT-WSI021 soil aggregate analyzer is mostly used for soil sampling and analysis in the laboratory. Soil aggregate structure plays an important role in soil fertility. A good agglomer structure should generally have three properties:

Having a certain size, too large or too small is not conducive to the formation of a proper pore ratio; It has multi-level pores, large pores can be ventilated and permeable, and small pores retain water and fertilizer; It has a certain stability, i.e., water stability, mechanical stability, and biological stability. Good aggregate structure is the basis of soil fertility, and the relationship between aggregate structure and soil fertility is mainly manifested in the following aspects: regulating the contradiction between soil moisture and air; Coordinate the contradiction between the consumption and accumulation of soil nutrients; Stabilize soil temperature and regulate soil thermal conditions; Improving soil tillage is conducive to crop root extension.

The QT-WSI021 soil aggregate analyzer can analyze standard size soil particles without affecting soil structure. The instrument contains 4 analysis buckets, 5 standard pore sizes (mm, separators, through the analysis body moves up and down in the water, and finally analyzes the aggregates of 5 particle sizes from the soil.

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Soil microaggregates refer to the aggregate structure of the soil particle size ().

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Because it's easier to retain water and fertilizer! The same investment harvest is better than a sand harvest!