Analysis of the chemical composition of soils

• Why is the analysis of the chemical composition of the soil carried out?
• How to analyze soil samples?
• Parameters determined in soils
• What methods are used to determine the composition?
• Hach solutions for soil testing

Why soil testing is essential?

Chemical analysis of soil composition is often necessary to determine the degree of soil contamination, to select a reclamation method, or to select a suitable fertilizer. The latter is highly demanded in agriculture to increase the quantity of the crop and its quality. Also, methods similar to determining the composition of soils are sometimes used to analyze some components of solid waste, which can also be useful.

Soil samples analysis

It is first necessary to obtain a solution containing the substances that make up the analyzed soils. To accomplish this task, special extracts are prepared. There are many types of soil extracts, the main ones are:

1. Aqueous extract - the analysis of soil-water extracts is carried out by mixing a soil sample with distilled water and subsequent filtration, in such an extract, water-soluble compounds are determined;
2. Acid - formed in a similar process when using certain acids, it is used to determine substances or their forms that are soluble in acids or with different solubility;
3. Salt - formed by the interaction of salt solutions with a soil sample;
4. Ammonium-acetate - prepared using an acetate-ammonium buffer solution, used for the determination of heavy metals in the soil.

There are other types of extracts (for example, alcoholic or alkaline) depending on the solvent used, the choice depends on the substances which concentration is to be determined.

Also, in some cases, an analysis of the soil solution can be carried out, which is the moisture contents in the soil in natural conditions, obtained by pressing.

Parameters determined in soil

State environmental monitoring is carried out over the quality of soils. The indicators for which control is carried out are indicated in government regulations. The common testing parameters are:

• Chemical substances:
  Inorganic: heavy metals, nitrates, sulfur, hydrogen sulfide, sulfuric acid, fluorine;
  Organic: gasoline, benzene and some of its derivatives, baenzapyrene, etc .;
• Polychlorinated biphenyls;
• Microbiological contamination;
• Poisonous substances and products of their destruction;

In order to optimize economic activities on the territory, pH, salinity and humus content can also be determined.

Methods for chemical analysis of soil

After extraction, a wide variety of analysis methods can be used.

• Potentiometric. They are used to determine pH using electrodes and potentiometric converters. It is possible to measure soil pH directly using special devices.
• Titrimetric. Titration is used for the selective or total determination of metals and other components.
• Atomic spectroscopy. Atomic spectroscopic methods can provide data on the elemental composition of a sample. They are based on the fact that substances are destroyed by burning and the device reads the spectra of each of the elements. However, the method is quite expensive and does not always provide the necessary information.
• Colorimetric. Colorimetry allows you to determine the content in a sample of certain compounds that are either colored or acquire color as a result of preliminary chemical transformations. In the process of measurement, the optical density of the analyzed sample is compared with a standard that does not contain the compound being measured.

Hach solutions for any soil analysis method

Potentiometric methods

Various single and multi-channel meters are presented on the AquaAnalytics website. These devices can be equipped with various electrodes / sensors, depending on the parameters to be measured. The catalog also contains various sensors for both laboratory conditions and industrial / field. Fiels probes are characterized by a more robust housing and cable, which allows to measure a parameter directly in the technological cycle. Conductivity meters allow you to determine the total concentration of salts in the sample (salinity).

Titrimetric

Hach manufactures automatic laboratory titrators and application kits for a variety of applications. In addition to laboratory titrators, the Hach range also includes a manual titrator that can be used for analysis both in the laboratory and on site. The choice of cartridges and reagents for a portable titrator depends on the substance, the concentration of which is to be measured.

Colorimetric

Spectrophotometers are suitable for colorimetric measurements, while the DR900 handheld colorimeter is suitable for field conditions. A huge advantage of using Hach instruments is the programmed methods. Their combination with ready-made reagents - cuvette tests LCK and TNT eliminates the need for calibration charts and preparation of blanks, which greatly simplifies and speeds up the analysis process. Hach manufactures reagents for the analysis of various parameters presented on our website.

If you need to perform a rapid analysis to estimate the content of chemicals in the soil, it is possible to use test strips and color discs.

A ready-made test kit in the form of a portable laboratory NPK-1 allows you to immediately purchase everything you need for soil fertility assessment, determining such parameters as nitrogen, potassium and phosphorus concentration.

Soil is a complex system of interactions between chemical, biological and physical processes. These interactions must be well balanced in order to grow and produce high yields. Poor soil quality, poor absorption of mineral elements, salinity and soil depletion lead to a number of problems and high costs. Soil analysis is carried out in order to avoid or at least minimize possible costs and ensure the quality of the crops grown.

AquaAnalytics®💧 is the official representative of Hach in Russia and the CIS countries. Contact us and our specialists will select the necessary kit for analyzing soil quality parameters.

Representative office in Russia: +7 (495) 201-53-02 info@aquaanalytics.ru

Representative office in Uzbekistan: +998 (90) 174-57-84 info@aquaanalytics-tekhnika.ru