MONITORING OF ACTUAL STATUS AND DEVELOPMENT OF ACTIVE ALUMINIUM IN SOILS IN SLOVAKIA

Active aluminium contents in agricultural soils of Slovakia were evaluated in the frame of partial-monitoring system - soil. The soil samples were taken in 5 years regular intervals from depths of 0-0.10 and 0.35-0.45 m. In the dry homogenised samples, soil reaction (pH in CaCl₂), exchangeable cation Ca²⁺ and active Al content by Sokolov (soil is extracted with 1 N KCl and Al is precipitated with NaF) in the samples with pH value lower than 6.0 were measured. Active Al content was in the range 0.10-684.0 mg/kg with the average value 59.28 mg/kg and median value 8.30 mg/kg in the depth 0-0.10 m. In the depth 0.35-0.45 m, the average value was 59.30 mg/kg and the median value was 9.00 mg/kg. Significant differences in average and median values between the arable land and permanent grassland are determined as a consequence of the relationship between soil quality and its use. The increase in the active aluminium content (between first and last monitoring cycles) was determined in the group Podzols, Lithic Leptosols used as the permanent grassland as well as in the group Cambisols on the crystalline rocks and in the group Fluvisols used as arable land.