Preliminary assessment of the ecochemical condition of soils after fertilization of younger spruce Picea abies (L.) H. Karst. stands in the Beskid Slaski and Zywiecki Mts.

Abstract

The experimental plots were located in the middle forest zone (900– 950 m) on two nappes of the flysch Carpathians: Magura (the Ujsoly Forest District) and Silesian (the Wisla Forest District) in the spruce stands of age class 21– 40 years. Serpentinite was introduced in the autumn of 2008 on all plots while other fertilizers (N, P, NP and NPK) in the spring of 2009. Based on the chemical composition of soil solutions collected in lysimeters placed at the depth of 20 cm in the autumn 2008 and the spring and autumn 2009, ecochemical parameters were calculated: acid neutralization capacity (ANC aq ) , alkalinity (ALK), the degree of soil acidity (Ma%), acidic cations (Ma), saturation of the exchangeable complex of the soil solid phase (Mb) with alkalis, saturation with alkalis (BS), molar relations Ca/Al, Mb/Al, BC/Al. After the winter, soil solutions became acidic, especially in the Wisla Forest District. The saturation of the studied soils demonstrates moderate flexibility of soils in the Wisla Forest District in relation to acid load, and high flexibility of the Ujsoly soils. The opposite trend was observed for the degree of acidity of soils. Acid neutraliza tion capacity and alkalinity of the waters showed significant variations in soil pH even in the case of small variations in the composition of the solution, if they were caused by the inflow of the anions of NO 3 - and SO 4 2- . After application of the fertilizers, an increase of Mg, Ca and Mb was noted in the soil solution, determined in the overlaying highly acidic organic horizons trough the ion-exchange buffering mechanism of highly protonated functional groups with high buffering capacity. Highly improved content of Mg in a soil, and in some cases – also the content of N, P and K, present potential improvement of forest growth capacity without the hazard of adverse side-effects of liming. Aluminum stress in the spruce is unlikely, while trees in the control plots in the Wisla Forest District may already be sensitive.