Soil structure is understood as the ability of the earth to break down into separate mechanical elements, that is, structural aggregates. There are two types of soil - structured and structureless. Depending on this, other types are distinguished, which differ from each other in characteristics. It is worth considering that it is structural soil that has high fertility rates.
What is soil structure and which is considered the best?
There are two concepts - structure and structure of the soil. Structure - the shape, size and arrangement of individual particles into which soil breaks down.Structurality is the ability of the earth to break down into aggregates, the size and shape of which differ depending on the type of structure.
Individual parts of the soil are called aggregates, which are a natural component of the soil. Formed by smaller aggregates or soil particles under the influence of a physical, chemical, physicochemical or biological process.
Characteristics of soil structure types:
| Type name | Description |
| Cuboid | Aggregates that have the same shape along three axes. The following types of cube-shaped soil are distinguished:
lumpy (lumps with poorly defined corners, edges larger than 5 cm); · lumpy (aggregates with the same characteristics as the blocky type, but the volume is from 5 to 0.5 mm); · nutty (aggregates are distinguished by pronounced angles and edges, the volume of which ranges from 20 to 5 mm); · granular (aggregates have the same characteristics as the previous type, but the shape is from 5 to 0.5 mm). |
| Prismatic | The units are developed along the vertical axis. There are several types: columnar (irregular in shape, with weakly defined edges and edges), columnar (with a rounded top and flat base), prismatic (with flat, glossy edges and sharp edges). |
| Slab-shaped | The units are developed along two horizontal axes and are also shortened vertically. A distinction is made between platy (layered with developed horizontal cleavage planes) and scaly (with planes curved upward and often sharp ribs). |
The best option for farming is a lumpy soil structure. This is due to the fact that the composition includes different sizes of units. Land of this type can be cultivated without any problems.
What does it depend on
The structure of the soil directly depends on:
- from the mechanical composition;
- on the amount of humus;
- on the ability to absorb and retain liquid, as well as supply water to the surface.
Depending on the mechanical composition of the soil, there are clayey, loamy, sandy loam, and peat bogs. To determine the composition, it is necessary to collect soil from the site.
What does it affect?
The structure of the soil affects the penetration of oxygen to the root system of plants, fluid retention, and the development of beneficial microorganisms. The size of the aggregates can also influence the yield. Optimal for the development of crops is one that predominantly contains particles ranging in size from 0.25 to 7-10 mm.
Methods for determining structure
To determine the structure of the soil, the dry sieving method or sieve analysis is used. This technique helps to determine the percentage of fractions in a material that consists of particles of a certain shape.
Analysis is carried out by sifting the material through a set of standard sieves that differ in size. The cells in the sieve are square or rectangular in shape. The lower the sieve is, the smaller the cells. Soil particles smaller than the mesh size pass below to the next sieve, while larger particles are retained at the top. 5-15 sieves can be used for analysis. It must be remembered that the number of fractions is always one unit greater than the number of sieves.
Sieves are made of wire or thread. But they can be found from a metal lattice. To sift out small particles, small nickel foil sieves are used. These sieves have square cells and widen towards the bottom. This eliminates clogging.
The content of fractions is calculated by the ratio of the fraction to the sample taken. The unfavorable agrophysical state of the soil structure indicates the presence of large and very small aggregates. Particles from 10 to 0.25 mm are considered the most important, as they impart soil fertility to the structure. That is why they are called agronomically valuable.
