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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Biochar application to agricultural soils has a significant potential to influence soil resource availability and thus crop performance. A factorial experiment investigating effects of different biochar application rates combined with nitrogen fertilizer was conducted in field conditions on a Haplic Luvisol. The aim of this study was to evaluate the effects of biochar and biochar combined with fertilization on soil organic matter and soil structure parameters. The treatments comprised combinations of biochar application of 0, 10 and 20 t ha

Dynamics, structure and properties of plant litterfall in a 120-year old beech stand in Middle Pomerania between 20072010Abstract: Studies of plant litterfall mass, its dynamics, structure and chemical composition were conducted between 20072010 in a 120-year old beech (Fagus sylvatica L.) stand located in Middle Pomerania. The annual mass of litterfall during the study period ranged from 2.793 to 5.398 t·ha 1 and its maximum was observed during the seed year. Leaves were the major component of plant litterfall and their contribution was 82.484.5% in the non-seed years and 47.2% during the seed year. Inflorescences, seeds, and seed coats were important components of litterfall during the seed year and accounted together up to 39.8% of the total litterfall mass. Particular fractions of litterfall significantly differed in the chemical composition. The highest concentrations of nitrogen, phosphorus and potassium were noticed in seeds and leaves collected in spring and the maximum content of calcium was observed in leaves collected in autumn. The weighted mean annual concentrations of nitrogen ranged within 0.811.13%, phosphate 0.1260.153%, potassium 0.2980.485% and calcium 0.4160.583%. The influx of elements with litterfall to the soil was: 167.3225.9 kg·ha 1 of ash, 23.261.0 kg·ha 1 of nitrogen, 3.67.6 kg·ha 1 of phosphorus, 8.326.2 kg·ha 1 of potassium and 15.322.4 kg·ha 1 of calcium.

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