Conductometry (electrical conductivity)
Conductivity (from English Conductivity – Electrical Conductivity and Greek. Metreo – Measure) – a set of electrochemical methods of analysis based on measuring the electrical conductivity of various mixtures and solutions. Advantages of conductometry: high sensitivity (lower limit of the estimated concentrations ~ 10-4-10-5M), fairly high accuracy (relative error of determination – 0.1-2%), simplicity of techniques, availability of equipment, the ability to study stained and muddy solutions.
Electrical conductivity of the soil – the ability of the soil (suspensions) to conduct an electric current. Depending on the soil moisture, the phase state of moisture, the content in the soil of salts, its temperature, density, granulometric composition, etc., is quantitatively characterized by the coefficient of specific electrical conductivity of the soil.
Coefficient of specific electrical conductivity of soil – quantitative characteristic of electrical conductivity of soil. Equal to the coefficient of proportionality between the electric current density and the gradient of the voltage of the electric current.
Specific electrical conductivity is used to estimate the total amount of sodium, potassium, calcium, chlorine, sulfate, hydrocarbon dissolved in water (suspension) dissolved in water. The presence of ions of two- and trivalent iron, manganese, aluminum, nitrate, etc. does not have a serious effect on electrical conductivity (unless, of course, these ions are not contained in significant quantities). The conductivity varies with the temperature, which often leads to a slight measurement error. However, modern devices allow to minimize the measurement errors due to the calculated and stored in memory of the physical dependencies of the specific conductivity on temperature. With the help of electric conductivity it is possible indirectly to estimate the electrochemical composition of the soil according to the methods studied and to compare it with the parameters of the medium.
When measuring the salinity of the soil, in essence, measurements of inorganic salts dissolved in water are carried out. All salts contain some water-soluble part, which at achievement of a certain level has a detrimental effect on plant growth – there is a salinity of the soil. Salinity is the result of low soil permeability.
Soil soil is determined by measuring the electrical conductivity of the soil suspension and expressed in μS / cmil in mS / cm.