Soil is a heterogeneous dispersed system containing 3 phases: solid, liquid and gaseous. Soil density indicators are a physical quantity that depends on the composition of the soil and affects productivity, moisture and air permeability. Therefore, its values are important when determining the type of crops for optimal agricultural development in the region.
Understanding soil density
Soil density is the mass per unit volume of absolutely dry soil taken in its natural composition. Recorded in grams/cubic centimeter.The indicator depends on the amount of organic component in the soil, mineralogical, and granulometric composition. It can change during mechanical cultivation of the land, under the influence of mechanisms, due to its large weight.
The soil becomes loosest after plowing and harrowing, gradually compacting during the season and reaching constant values characteristic of a certain region. At values above 1.7, cultivation of any crops is impossible.
There are equilibrium constant, optimal, and critical densities. Using it, you can determine the classification of the soil and find out which crops it is suitable for cultivating.
| Density value, grams/cubic centimeter | What plants is the soil suitable for planting? | Ways to improve |
| 0,8-0,9 | Potatoes, vegetables | 1 digging, sowing green manure, applying organic fertilizers. |
| 0,9-1,0 | Optimal for vegetables, root vegetables, potatoes | 1 dig, about 3 kilograms of manure per square meter. |
| 1,0-1,2 | Vegetables grow worse, for root crops it is optimal | 1-2 diggings, adding organic matter, green manure |
| 1,2-1,4 | Suitable for cereals and berry bushes, not suitable for vegetables and potatoes | Adding sawdust and peat every 4-5 years to loosen the soil, sowing oats and buckwheat, organic matter, 2 diggings |
| 1,4-1,6 | Most crops do not grow | Adding peat and sawdust every 2-3 years, sowing green manure every 2 years, adding organic matter, regularly loosening the soil. |
| More than 1.6 | Critical Density | — |
High values affect the degree of oxygen supply to plants, the development of the root system, and the ability to retain moisture. That is why, the higher they are, the less suitable the area for cultivation, the more effort must be made to obtain a good harvest.
What does it depend on?
The level of physical quantity values depends on the mineralogical composition, quantity and quality of the organic component of the fertile layer. For example, the presence of a large amount of peat in the ground reduces density. The indicator is influenced by the quality of processing of the fertile layer. Now let's look at the categories of soil density:
- Equilibrium constant density is the level that the soil acquires some time after mechanical treatment; it depends on the quality of the soil on the site.
- Optimal - these are the indicators that are best for the growth and development of the selected crops on the site. Value – from 0.9 to 1.2.
- Critical is the value at which the soil has the greatest density. It is no longer possible to plow it open and return it to normal. From 1.6 to 1.9.
Indicators of equilibrium and optimal values can differ significantly.
How to determine it?
Usually the indicator is determined in the laboratory; when independently establishing the values, you need to take a glass container (for example, a jar with a capacity of 250 or 500 grams), weigh it empty, with an accuracy of 1 gram. Fill the container with soil to the brim without breaking the lumps. Place the jar of soil in the oven and leave for 5-6 hours at a temperature of 90-100 °C. Weigh the container after cooling and calculate the density. It is necessary to divide the mass of dried soil by the volume of the container.
