Fluorine content in soils of Northern Pomoravlje

Soil sampling was carried out in the Velika Morava river valley, covering the area from Velika Plana to the mouth of Morava to the Danube. The composite soil samples, representing alluvial soils (22 samples), cambisols (14) and smonitzas (4), were taken from plough layers, based on a regular square grid with intervals set at 5x5 km, covering total area of 100,000 ha. The total and available fluorine contents were determined in the soils samples. The highest average amount of total fluorine was found for alluvial soils (391 mg kg-1), then for smonitzas (348 mg kg-1) and the lowest one for cambisols (285 mg kg-1). These amounts are within normal fluorine content for soils (150-400 mg kg-1), although the maximum found levels were even about 500 mg kg-1. The available fluorine content was very low (< 1 mg kg-1), being mostly less than 0.2 % from its total amount, so it could be concluded that there was no danger from fluorine accumulation in the plants. Statistically significant correlation coefficient between total and available fluorine contents was not obtained. The total and available fluorine contents have mostly been in the correlation (with positive sign) with soil pH and the content of mechanical fraction silt+clay. Significant correlation coefficients between total fluorine content and the content of some heavy metals (Cr, Ni, Co, Cu, As) were also found, which indicated their mutual geochemical origin.