Soil acidification in top layers (measured as its intensity and range in soil profile) is related to the value of acid rainfall and causes particular changes in chemical and physicochemical features.
The model research presents reaction of degraded chernozem to acidification. Determining the level of soil acidification, in which strong chemical degradation occurs, was an aim of our investigation.
A model study upon the degraded chernozem reaction toward the acidifying action of simulated acid rain was performed in columns of 1 m height and 7 cm diameter. The acid rain was divided into 20 doses of 80 ml per each column and was applied daily in six doses equivalent to 25%, up to 150% of the sorption capacity of Ap horizon.
The surface application of hydrogen ions within Ap horizon of reconstructed chernozem profile invokes the decrease of pH value of the soil solution and hydrolytic acidity till the complete saturation of the sorption complex with hydrogen cations at concentration equivalent to 150% of sorption capacity of Ap horizon (level VI), proportional to the acid concentration. Reaction toward acidifying gradually weakens in deeper layers. The basic cations eliminated out of the surface horizons at low amounts were removed along with filtrates out of the soil profile in the following sequence: Ca>Na>Mg>K; they were retained mainly in deeper horizons.
Acid rain application in a dose equivalent to 50% of the sorption capacity of Ap horizon of degraded chernozem provokes substantial deterioration of chemical and physicochemical features, while in deeper layers it is less visible. Strengthening the acid rain (over 50% of the sorption capacity of Ap horizon) increases the negative effect and enlarges its range in soil profile.