Soil Reaction

Soil Reaction


a physicochemical property of soil functionally related to the concentration of H+ and OH- ions in the solid and liquid parts of the soil. If H+ ions are predominant, the soil reaction is acid; if OH- ions are predominant, it is alkaline. If the concentrations are equal, the soil reaction is neutral. The pH of soils in the USSR varies from 4 to 8.2.

The soil reaction plays an important part in the migration of products of weathering. The migration capacity of Fe, Mn, Sr, and Cu compounds increases in an acid medium, while that of Si and Al compounds increases in an alkaline medium. The soil reaction greatly affects the metabolic level of plants. Because many plants are harmed by a high concentration of [H+] and [Al3+] ions when the soil reaction is acid, acid soils must be treated with lime. Such strongly alkaline soils as solonetz soils and sodium carbonate solonchak soils, which have a high concentration of [OH-] ions and lack structure, are also unfavorable for plant growth and development.

The application of gypsum combined with organic fertilizers neutralizes an alkaline soil reaction and improves the soil’s agronomic properties. Indicators used to determine the soil reaction quantitatively include the pH of a soil suspension in water or a KC1 solution and titratable acidity or alkalinity.


Serdobol’skii, I. P. “Metody opredeleniia pH i okislitel’no-vosstanovitel’nogo potentsiala pri agrokhimicheskikh issledovaniiakh.” In Agrokhimicheskie metody issledovaniia pochv. Moscow, 1960.
Rode, A. A., and V. N. Smirnov. Pochvovedenie, 2nd ed. Moscow, 1972.
Kovda, V. A. Osnovy ucheniia opochvakh, book 2. Moscow, 1973.


References in periodicals archive ?
The production potential of the land depends on the organic matter in the soil, the composition of organic matter, carbon-nitrogen ratio, cation-anion exchange capacity, soil reaction, buffering capacity of the soil, nutrient transformation and fixation in soil etc.
Soil particle size distribution (texture) was determined with a hydrometer (Bouyoucus, 1962), calcareous content with a Scheibler calcimeter (Allison and Moodie, 1965), organic carbon content with Walkley-Black method (Nelson and Sommers, 1982), soil reaction (pH) with a pH-meter in a 1: 2.
Soil reaction (S1-S6) was measured by the potentiometric method in a water suspension 1:5 (m/V) using a Slandi pH meter SP300.
Maize requires abundant of readily available plant nutrients and soil reaction between 5.
Crop productivity depends on soil health whose indicators are amount of essential nutrients, soil reaction, activities of enzymes and microbial population in soil.
The modulus of soil reaction can be determined in the following ways:
The assessment of soil reaction shows that we are in an acidic atmosphere environment and there is no significant difference between the actual acidity (pH water) and potential acidity, indicating a strong desaturation of the adsorb complex along the profile.
For comparing the analysis of soil reaction to pollution by heavy metal, sod-podzol soil was studied.
10]), which means that such forms are naturally preferred under circumstances of the registered minimal variations in soil reaction (pH).