MULTIVARIATE ANALYSIS OF SPACE VARIABILITY IN SOIL CHEMICAL PROPERTIES

Koptsik Serguei ⁽¹⁾, Zhuravleva Mariya ⁽²⁾

Annotation:

Space variability of acidity and exchangeable cations is analysed in surface soil organic horizons of podzols in pine and birch forests on the northern tree line near the major pollution source in European North – the Pechenganikel smelter in the Kola Peninsula, Russia.

Multivariate analysis show that both natural and anthropogenic factors effect the acidity and exchangeable cation content in soil organic horizons. Soil pH increases, while exchangeable acidity decreases towards the smelter mainly due to combined effects of deposited base cations, vegetation disturbance and geology. Decreased concentrations of exchangeable K towards the smelter reflect its replacement in exchange complex caused by enhanced input of Ni, Cu and Fe. The concentrations of exchangeable Ni and Cu in soils near the smelter are approximately one to two orders of magnitude higher compared to background levels. The organic horizon of podzols appeared to be the important accumulator of heavy metals and the barrier against transport of pollution to underlying mineral horizons.

Principal component analysis is a useful tool for graphical representation of data, for delineation of the objective inner structure in soil chemistry and for analysis of changes under the influence of air pollution. Natural sources of variation appeared to be the most significant, and main soil nutrients determining the first principal component form first isolated group in ordination plot. Variation of exchangeable Ni, Cu and Fe caused by heavy metal deposition from the smelter, is very high; these variables determine the second component and form a second group in ordination plot. Like heavy metals, second component nonlinearly depend on distance from the smelter. Sulphur and exchangeable acidity, that is determined by pollution induced H+ input, are the main factors contributing to third PC and form a third group of elements. The results on natural grouping of elements is confirmed by cluster analysis. Sensitivity analysis show that obtained ordination diagram is characteristic for the studied region, reflecting both natural and pollution induced soil variability.

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