Soil quality index for agricultural areas under different levels of anthropopressure

Different individual soil parameters or simple indices are widely used in soil quality evaluation, but this approach has many limitations. The aim of the study was to determine an integrated soil quality index in agricultural soils as affected by different levels of anthropopressure. The soil quality index was calculated through: the selection of the appropriate indicators for a minimum data set, score assignation for selected indicators and the integration of indicators in an index. The study was carried out in two areas under agricultural use with similar soil cover but with a different history and intensity of exposure to pollution input. Soil samples collected from the surface layer (0-30 cm) were analysed for physicochemical (i.e. texture, fractional composition of soil organic matter, pH), and biological (respiration, dehydrogenase activity, microbial biomass and nitrification) properties and the levels of contaminants (16PAHs and heavy metals). The level of anthropopressure was assessed on the basis of pollutants emission indices. A statistical evaluation based on principal component analysis enabled the selection of indicators of significant importance to soil quality. The level of anthropopressure was found to be an important factor influencing soil quality; higher soil quality index values (0.50) were determined for the area of low anthropopressure.