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.
Highlights 1. Agreement between observers allows for statistical comparison of soil water repellency results 2. Best average CA compatibility was observed between the WDPT/MED and sessile drop methods 3. WDPT below 5 s relates to an average CA below 40° for hydrophilic samples 4. Good relationship between MED and CA were obtained for a range of hydrophobic samples 5. CA ranged from 110 to 130° for strongly hydrophobic samples (600 s < WDPT < 3600 s)
Hot and cold water-extractable organic carbon (HWC and CWC, respectively) fractions, as good indicators of organic matter quality, as well as water repellency (WDPT test) and state of secondary humification were analyzed in topsoil samples of peatland drained for agricultural purposes 160 years ago. The examined sites (drained and used as grassland) at the peatland had been affected by the moorsh-forming process. During this process, intense mineralization and secondary humification of organic matter took place. The state of transformation of organic soils varied from weak to complete degradation. The HWC contents ranged between 2.623 and 3.572 g kg -1 in field-moist samples and 3.999 and 6.074 g kg -1 in air-dried soil samples. The CWC contents were generally lower than HWC and ranged between 0.411 and 0.535 g kg -1 in field-moist samples and 0.696 and 0.939 g kg -1 in air-dried soil samples. The examined soils were extremely water repellent when dried. The measures of transformation of peat after drainage and WDPT were not significantly correlated, but a tendency for higher values of water repellency at the site regarded as degraded was noted. Deep drainage caused an increase of HWC fraction, which in light of the moorsh-forming process should be regarded as negative. The topsoil of the peatland became dry and resistant to rewetting. However, when the ground water level is maintained at not deeper than 0.50 m, the changes in peat matter do not lead to degradation. HWC is a good measure to show differences occurring within the ecosystem. Given its correlation with state of transformation (W1 index) and water repellency (WDPT test), HWC is a good measurement of peat quality. HWC and WDPT measurements may be helpful in determining degradation of peat soil after drainage.
The objective of this study was to estimate the water repellency of post-boggy soils in north-eastern Poland. Potential water repellency was determined based on the water drop penetration time (WDPT) test and the molarity of an ethanol droplet (MED) test. A total of 276 soil samples with a varied organic carbon (OC) content, ranging from trace amounts in sandy subsoils to 44.4% in organic soils, were analyzed. The investigated material represents peat-muck soils (Eutri-Sapric Histsols) and muck-like soils (Arenic Gleysols, Areni-Humic Gleysols, Gleyic Arenosols). The mineral matter of the analyzed soils comprised loose sand. The obtained results indicate that peat soil formations are marked by higher potential water repellency than muck soil formations. The highest WDPT values (16 390 s) were reported in respect of an alder peat sample with 41.9% OC content, collected at a depth of 55-60 cm. In the group of muck soils, a sample with 36.7% OC content, collected at a depth of 15-20 cm, was marked by the highest water repellency (WDPT 10 492 s). The water repellency of the studied soils is dependent on organic matter content, and it is manifested only when organic matter content is higher than 20%. Soils with OC content of up to 12% show low water repellency or are hydrophilic. Organic soil formations (>12% OC) are characterized by a varied degree of water repellency, but WDPT values in excess of 2000 s are reported only in respect of soils containing more than 35% OC. A significant positive correlation between the content of organic matter, organic carbon, total nitrogen and water repellency was observed in the entire studied population (n = 276). A significant positive correlation was also found between WDPT values and the C:N ratio, while a significant negative correlation was reported in respect of pHH 2 O.
The goal of the study was to assess the levels of plant available nutrients in the soils of the Antarctic oasis of Point Thomas in the vicinity of Polish Antarctic Station H. Arctowski. Antarctic soils are undergoing transformations in the era of climatic changes and it is important to quantify changes in soil properties and determine the relationships between soil properties and ecological gradient. Total C and N were determined using CN analyser, mineral forms of nitrogen were determined colorimetrically, plant available P and K was analysed with Egner-Riehm method, Mg with Schachtschabel method and Fe, Mn, Cu, Zn were determined in 1M KCl using AAS (Atomic Absorption Spectrometry) method. The amounts of analysed compounds were dependent on organic matter, which was influenced by plant succession, and in some sites by the activity of seabirds. Most of organic matter was accumulated in the vicinity of penguin colony. All studied soils were abundant in plant available forms of studied macro-and micronutrients. In addition to translocation of biogens (mainly N and P) from the sea to the land by piscivorous birds, a dispersion of biogens on the entire ice-free area occurs. It is related to the occasional appearance of scua as well as the eolian topsoil dust input.
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