The sixth edition of the Polish Soil Classification (SGP6) aims to maintain soil classification in Poland as a modern scientific system that reflects current scientific knowledge, understanding of soil functions and the practical requirements of society. SGP6 continues the tradition of previous editions elaborated upon by the Soil Science Society of Poland in consistent application of quantitatively characterized diagnostic horizons, properties and materials; however, clearly referring to soil genesis. The present need to involve and name the soils created or naturally developed under increasing human impact has led to modernization of the soil definition. Thus, in SGP6, soil is defined as the surface part of the lithosphere or the accumulation of mineral and organic materials permanently connected to the lithosphere (through buildings or permanent constructions), coming from weathering or accumulation processes, originated naturally or anthropogenically, subject to transformation under the influence of soil-forming factors, and able to supply living organisms with water and nutrients. SGP6 distinguishes three hierarchical categories: soil order (nine in total), soil type (basic classification unit; 30 in total) and soil subtype (183 units derived from 62 unique definitions; listed hierarchically, separately in each soil type), supplemented by three non-hierarchical categories: soil variety (additional pedogenic or lithogenic features), soil genus (lithology/parent material) and soil species (soil texture). Non-hierarchical units have universal definitions that allow their application in various orders/types, if all defined requirements are met. The paper explains the principles, classification scheme and rules of SGP6, including the key to soil orders and types, explaining the relationships between diagnostic horizons, materials and properties distinguished in SGP6 and in the recent edition of WRB system as well as discussing the correlation of classification units between SGP6, WRB and Soil Taxonomy.

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The paper deals with the amounts of total and plant available forms of heavy metals (Pb, Cr and Cu) and relation between soil properties in three catenas in postglacial area of the Łyna River valley, NE Poland. The results were presented on the background of four geochemical landscapes distinguished within the study area: eluvial or trans-eluvial, eluvial accumulative, trans-superaqual and super-aqual. The average total content of heavy metals amounted to: Pb -14.05 mg kg -1 d.m., Cu -9.96 mg kg -1 d.m. and Cr -46.25 mg kg -1 d.m. The share of plant available forms in total forms of HM amounted on average: Pb -30.13%, Cu -37.10% and Cr -1.28%. In spite of relatively low levels of heavy metals in soils of the studied area, the amounts of metallic forms varied between geochemical types of landscape. The analysis, supported by PCA ordination, resulted in significant relations between heavy metals contents and amounts of organic matter and clay fraction (< 2 µm) as well as inverse relation to the share of sandy and gravel fraction in soil. The most abundant in heavy metals were soils in superaqual geochemical landscape (Pb, Pba, Cu and Cua) and eluvial accumulative geochemical landscape (Cr and Cra). Based on the amounts of accumulated metals, the geochemical landscape types created the following order: super-aqual > trans-super-aqual > eluvial accumulative > eluvial / trans-eluvial.

The paper presents the research results on the relation between the contents of total zinc and its bioavailable form (Zn a) and physicochemical properties of soil carried out along three catenas in the postglacial valley of the middle Łyna River, in NE Poland. We focused on topographical factors to determine the amount of Zn in the soil in relation to specific geochemical landscape types. The analyzed soil showed a relatively low level of soil pollution with Zn and did not exceed the threshold values for soil contamination with Zn. The average Zn content amounted to 45.75 mg kg-1 d.m. and ranged from 8.80 to 176.26 mg kg-1 d.m. The heavy metal content in the soil was related to organic matter and clay fraction, while it was inversely proportional to the share of sandy fraction. Distribution of zinc showed variability due to factors derived from topography, soil heterogeneity in the river valley as well as fluvial processes taking place within the floodplain. Different geochemical landscapes showed depressive trends in both Zn and Zn a contents along the catenas. It diminished from eluvial to transeluvial landscapes and increased again to superaqual landscape. Depressions after former river channel were favorable for the Zn a accumulation. The most abundant in Zn a were upper horizons of Fluvisols in superaqual landscape (45.12 mg kg-1) filling overgrown and terrestialized floodplain lakes. The share of Zn a was the highest in organic horizons of Fluvisols and achieved 51.4% of total Zn. The nature and power of functional links between the heavy metal mobility and the soil properties were determined with multivariate statistics and GAM models. Applied ordination statistics confirmed its usefulness in soil factor analyses.

Abstract. The research was carried out in the hilly landscape in the Buskerud region, south Norway. The following soil toposequence was stated, beginning from the top of the slope: Epigleyic Pheozem (Siltic) -Cumullinovic Pheozem (Endosiltic) -Epigleyic Pheozem (Skeletic Endosiltic) -Cumullinovic Pheozem (Siltic) -Mollic gleysol (Siltic). The soils had a silt loam and sandy loam texture with a substantial admixture of gravel. The material was poorly sorted with a lepto -and platykurtic texture distribution. The amounts of organic matter, organic carbon, as well as total nitrogen and phosphorus did not show catenal changes.