The chemical composition of different soils varies significantly in the presence and level of chemical elements contained in them, as well as their compounds. These factors affect soil fertility and other indicators of plant-specific crops.
PH value
An indicator of soil quality is the acidity level corresponding to the degree of concentration of hydrogen ions in the earthen solution. It is called an indicator of acidity and is designated as pH.
The acidity of the soil depends on its chemical composition. It is acidic, alkaline and neutral. Alkaline and acidic soils are additionally divided by boundary gradations. Depending on the level of acidity, acidic soils are strongly, slightly and medium acid, and alkaline, similarly, slightly, strongly and medium alkaline. Acidity of the soil in terms of pH increases from acid to alkaline state. The neutral indicator is considered to be pH = 7. If it is less, then the soil is considered acidic, higher - alkaline. The value of acidity affects its quality, development and growth of plants. Plants can fully absorb the necessary nutrients only in neutral soil. Even a good fertilizer does not create conditions for the development of plants at a pH that is higher or lower than neutral.
Acidic soils are considered:
- pH = 4 and less are strongly acidic;
- pH from 4 to 5 - medium acid;
- pH from 5 to 6 - slightly acidic.
Neutral soils have a pH of 6.5-7.
Alkaline soils are considered:
- pH 7-8 is slightly alkaline;
- pH 8-8.5 is mid-alkaline;
- pH 8.5 and higher are strongly alkaline.
The acidity of the soil affects the degree of penetration into the tissue of plants of heavy metals contained in the soil. At neutral pH, heavy metals continue to remain in a bound state and only a small fraction of them accumulate in plants. At the same time, acidic soils with a low pH include a lot of aluminum, manganese and iron in a form toxic to plants.
Also with radionuclides: the pH value affects the degree of their absorption in plants. In this regard, we can definitely say that in neutral soil the necessary nutrients are optimally absorbed by plants, and the absorption of harmful substances is negligible.
Determination of soil acidity
Most plants prefer neutral and slightly acidic soils. Sometimes, the acidity of the soil can be estimated from the growth of weeds, but due to the fact that the weed grass is actively destroyed, it is hardly possible to accurately determine the acidity from it. How to determine the acidity of the soil? To determine it, you can use indicator paper (TU16-09-1181-71). In stores you can buy a set of filter strips. Filtered strips are painted in light orange color, they have a special indicator coating, which changes color depending on the pH level.
The table attached to the kit reflects the acidity of the soil depending on the color indicated.
To determine the level of acidity, the soil for analysis is taken at different depths in different corners of the site. The soil is wrapped in dense fabric, tied and placed in water. One part of the soil and 4-5 parts of water are taken. Then, test paper is immersed in the obtained earthen solution. The resulting color is checked against a scale for determining acidity.
To obtain an approximate analysis of the soil, you can use acid-base two-color paper, and for an even more correct analysis - “rifan”, universal paper, or other indicators with a small pH range. What to do if the soil in the summer cottage is acidic? To correct the situation, ash, chalk, lime, powdery building cement can be added to it. With strongly alkaline soil, you need to add soil with an acidic or neutral reaction, while thoroughly mixing different types of soil.