The influence of fertilizers application on the properties of seasonally-frozen soils on limno-glacial clays on the background of liming and manuring was studied. For the study of agrochemical properties and mineralogical composition, soil samples were collected from the depth of 0-10 and 10-20 cm after 1, 3 and 6 years of experiment. The research showed that the changes of soil properties, favourable for the plants, in comparison with the check, took place in most variants of experiment: pH, exchange cation capacity and degree of cation saturation were increased and hydrolitical acidity was decreased. Quantity of phosphorus and potassium, available for plants, was increased in the variants of experiment with high NPK dozes. The results of the mineralogical study of thin soil fractions were processed with the factor analisys methods. The results prove that fertilizer application doesn't stop the process of mineral wheathering. Usage of only nitrogen fertilizers activised the wheathering of minerals, that contain biofilic elements (micas, hornblends, chlorytes).

Tatiana S. Zvereva
Agrophysical Research Institute
195220, Grazdansky prospect 14
St-Petersburg, Russia
phone (812) 534-46-21
fax (812) 535-52-20
E-Mail ivl@agrophys.spb.su