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An assessment of hysteresis in studies on the hydraulic conductivity of peat soils

100%

Brzostowski E., Olszta W.

Zeszyty Problemowe Postępów Nauk Rolniczych

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1996

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tom 436

The value of hydraulic conductivity (K) has considerable theoretical and practical significance for the water economy of soils and plants. Measurements of hydraulic conductivity conducted for peat soils in the process of soil monolith drying and wetting indicated the occurrence of capillary hysteresis in the soils under study. Data presented in the paper may indicate that the phenomenon is directly affected by the physical-hydraulic properties of the soils. The hysteresis loop surface areas determined in the study may be insufficient to fully reflect the true situation as there is a lack of measurements of the soil water potential in the zone close to full saturation. Values of the surface area calculated according to statistical methods differ from values calculated according to Brooks and Corey’s formulae. A significant factor affecting the difference is the value of effective conductivity (Kₑ) which is one half of the conductivity at full saturation (Ks).

2

Verification of the Van Genuchten method of determination of the hydraulic conductivity of peat soils

100%

Olszta W., Kowalski D.

International Agrophysics

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1996

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tom 10

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nr 2

3

Enzyme activity in forest peat soils

88%

Blonska E.

Folia Forestalia Polonica. Series A . Forestry

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2010

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tom 52

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nr 1

The aim of the study was to determine the activity of dehydrogenases and urease in forest peat soils of different fertility. There were selected 23 experimental plots localised in central and northern Poland. The research was conducted on forest fens, transition bogs and raised bogs. The biggest differences in soil physical and chemical properties were detected between fen and raised bog soils while raised bog soils and transition bog soils differed the least. Statistically significant differences between particular subtypes of peat soils were observed for soil pH-H2O, pH-KCl, C/N ratio as well as the content of organic carbon, nitrogen, calcium and potassium. The highest average dehydrogenase activity in the soil surface level was observed in fen soils, and the lowest – in raised bogs soils. The results obtained on urease activity were similar. Differences in urease activity in the studied soil types were shown. Dehydrogenase activity did not reveal statistically significant diversity. The activity of urease was negatively correlated with the content of carbon, C/N ratio, hydrolytic acidity and moisture. Also the increase in enzymatic activity accompanied by the increase in pH has been observed.

4

Vertical and horizontal permeability measurements in organic soils

88%

Malinowska E. E., Szymanski A.

Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation

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2015

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tom 47

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nr 2

The paper is referring to vertical and horizontal laboratory permeability measurements in soft organic soils. The estimation of anisotropic permeability in soft organic soils, as peats, requires to use a special apparatus and the knowledge of proper analysis of the test results. During loading the void ratio decreases substantially that causes the changeability of the permeability. The change of permeability during the compression is very important because of the infl uence of the consolidation coefficient. Initial strain in soft organic soils appears very quickly, just after loading, and brings immediately the decrease of permeability. In most of the estimations, it is assumed that during the consolidation process the water flows just in the vertical direction. In soft organic soils, like peats, the consolidation theory should consider the changes of mechanical and physical properties in consolidation period, in both directions. The direct measurement of vertical and horizontal permeability of organic soil and the non-Darcian flow theory may be of considerable importance in estimating pore water pressure dissipation, and settlement rates in the consolidation model. In the paper, the method of investigation and the test results of the vertical and horizontal permeability are presented. The Modifi ed Rowe Cell Set for obtaining consolidation and fl ow characteristics in different directions is used.

5

Changes in the hydrophysical properties of peat soils under anthropogenic evolution

88%

Rovdan E., Witkowska-Walczak B., Walczak R., Slawinski C.

International Agrophysics

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2002

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tom 16

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nr 3

6

Dynamics of organic matter in peat soil under the conditions of sand-mix culture during 15 years

88%

Bambalov N.

International Agrophysics

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1999

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tom 13

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nr 2

7

The influence of the moorshing process of peats on changes of their water capacity caused by thermal drying

75%

Gawlik J.

Polish Journal of Soil Science

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1998

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tom 31

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nr 2

8

Phosphate and ammonium concentrations in groundwater from peat soils in relation to the water table

75%

Sapek A.

Polish Journal of Soil Science

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2008

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tom 41

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nr 2

139-148

Soils developed from low peat found in the Biebrza National Park in north-eastern Poland show that seasonal lowering of the groundwater table in peat soils can result in a measurable increase in phosphate and ammonium concentrations in the groundwater. The main reason for the very high concentrations of phosphate is the large amount of ammonium resulting from the ammonification process, the presence of which protects the phosphate from precipitation.

9

Methanotrophs responsible for methane oxidation in natural peats from Polesie Lubelskie Region

75%

Szafranek-Nakonieczna A., Stepniewska Z., Woloszyn A., Ciepielski J.

Acta Agrophysica

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2012

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tom 19

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nr 1

The potential of methanotrophic activity (MTA) has been investigated under labo-ratory conditions in three types of peatland profiles: high (H), transition (T) and low (L) originating from Polesie Lubelskie Region. Selected peat samples differed in respect of pH, TOC, von Post index and moisture. The experiment was conducted at natural moisture (198-719 %w/w) with dif-ferent ranges of both, temperature (5, 10 and 20°C) and CH4 enrichment (1 and 5%v/v). The highest MTA (19.69-155.79 mg CH4kg D.W.-1 d-1) was observed at 20°C. Regardless of temperature, MTA was lower (1.38-51.16 mg CH4 kg D.W.-1 d-1) when peat samples were incubated in atmosphere enriched in 1% than in 5% CH4 v/v (4.75-191.26 mg CH4kg D.W.-1 d-1). Strong influence of tem-perature and sampling sites on MTA was also noted. Total DNA was isolated from the most active (20°C, 5% CH4 v/v) peat samples from each site and the PCR (polimerase chain reaction) amplify-ing of genes pmoA (primers A189f/mb661r) and sequence 16S rRNA (primers Type If /Type Ir and Type IIf/Type IIr) specific for methanotrophic bacteria were carried out. Positive results of PCR with primers of pmoA gene after sequencing confirmed that methanotrophs from L point belong to family Methylococcaceae, while 16S rRNA gene sequences from microorganisms inhabiting H peat demonstrated the highest similarity to genus Methylocystis and Methylosinus.

10

Derivation of consolidation partial differential equations with non-linear flow characteristics on organic soil example

75%

Malinowska E. E., Bursa B. A., Szymanski A.

Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation

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2014

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tom 46

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nr 4

Derivation of consolidation partial differential equation with non-linear flow characteristics is proposed. The non-linear flow characteristics are obtained from flow-pump test on organic soil and described with empirical relationship. Several reasons were crucial to perform tests on organic soil. Firstly organic soils are very compressible, so that results in high permeability changes. Even with small stresses organic soil deforms a lot. Secondly road embankments, flood control levees, dykes and dams are very often located on organic soil, so it is important to model deformations under these constructions. Thus to model consolidation process in soft organic soil one should consider as follows: physical and mechanical properties, non-linear stress-strain relationship, non-linear flow characteristics, and creep strains. This paper is focused mainly on non-linear flow characteristics that change with porosity and hydraulic gradient variations.

11

The analysis of some physical properties of drained peat-moorsh soil layers

75%

Oleszczuk R., Truba M.

Annals of Warsaw University of Life Sciences - SGGW. Land Reclamation

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2013

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tom 45

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nr 1

The paper presents the results of measurements of some physical properties for 14 drained fen peat-moorsh layers (degree of decomposition, bulk density, particle density, porosity and saturated moisture content). The soil samples were taken from north- -east, central and east part of Poland. These areas were drained in order to use as a grassland and meadows. The article presents obtained data of selected physical properties from several drained peatlands in Poland and shows the comparison of established results with relevant data published in literature.

12

N2O emission from high and low peat soils during flooding

75%

Stepniewska Z., Ostrowska A., Kotowska U.

Polish Journal of Soil Science

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2004

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tom 37

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nr 2

The changes of redox potential, pH, nitrate (V) concentration and N2O emission from high and low peat soils having been subjected to flooding were studied. Peat samples were taken from the Łęczyńsko-Włodawskie Lake District and incubated in a water-saturated state, under laboratory conditions, in the dark, at room temperature, for 55 days. Each week, the redox potential (Eh), and NO3- concentrations of the solutions collected and N2O content in gaseous phases were measured. The variations in the NO3- concentration in low peat soil were correlated with changes in the amount of nitrous oxide produced, indicating denitrification. The maximal N2O emission (15 mg N2O-N m-2d-1) from the low peat soil was measured at the beginning of the incubation.

13

The influence of dewatering and reclamation on water retention of peat soils in the sandy outwash landscape

75%

Piascik H., Lachacz A.

Polish Journal of Soil Science

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1997

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tom 30

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nr 2

14

Phenomenon of peat soil degradation in the light of experiments

75%

Okruszko H.

Acta Agrophysica

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2000

|

tom 26

The trial of explanation of the phenomenon of peat soil degradation was undertaken on the basic of literature and experiments carried out in cooperation between Polish and Belarussian institutes

15

Soil nematode response to root production in grassland on fen peat soils

75%

Wasilewska L.

Polish Journal of Ecology

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1999

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tom 47

|

nr 3

16

Verification of the Van Genuchten method of determination of the hydraulic conductivity of selected moorshed peat soils

75%

Brzostowski E., Kowalski D., Olszta W.

Journal of Water and Land Development

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1999

|

nr 03

The knowledge of hydraulic conductivity in unsaturated zone K(h) has a great theoretical and practical importance for soil water balance. The existing measurement methods of that parameter are rather complicated, so increasing interest appears in alternative, calculation methods. The article presents the results of laboratory tests of hydraulic conductivity of selected samples of peat soils, by dried monoliths method, and their comparison with calculated values obtained by Van Genuchten's formula with Mualem, Burdine and Brutsaert variation.

17

Simulation of an irrigation system for peat soils

75%

Kowalski D., Olszta W., Zaradny H.

Acta Agrophysica

|

2002

|

tom 68

18

Wilgotność krytyczna gleb torfowych jako kryterium nieodwracalności procesu pęcznienia

63%

Oleszczuk R., Gnatowski T., Brandyk T.

Acta Agrophysica

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2009

|

tom 14

|

nr 2[171]

W pracy przedstawiono zastosowanie metody TDR do określenia tzw. wilgotności krytycznych gleb torfowisk niskich (turzycowiskowe, olesowe, mechowiskowe i szuwarowe). Wilgotność krytyczna jest kryterium po przekroczeniu którego przesuszone gleby torfowe po ponownym nawilżeniu nie są w stanie powrócić do pierwotnej objętości przy stanie pełnego nasycenia. Ze względu na anizotropowy charakter procesu kurczenia w glebach torfowych na podstawie przeprowadzonych badań określono dla poszczególnych rodzajów torfu wartości wilgotności krytycznych po przekroczeniu których zachodzą nieodwracalne zmiany w wysokości i średnicy próbek glebowych pomimo ich ponownego nawilżenia. Opracowane wartości wilgotności krytycznych mogą stanowić podstawę do opracowania zasad racjonalnego gospodarowania wodą w procesie renaturyzacji wcześniej odwodnionych i zdegradowanych gleb torfowych.

19

The influence of sea on chemical properties of peat soil (Middle Pomerania, Poland)

63%

Trojanowska C., Trojanowski J., Janczak C., Bruski J., Antonowicz J.

Baltic Coastal Zone. Journal of Ecology and Protection of the Coastline

|

2001

|

tom 05

20

Characterization of the mechanical properties of muskeg site in pakdasht area

63%

Massah J., Noorolahi S.

Electronic Journal of Polish Agricultural Universities. Series Agricultural Engineering

|

2010

|

tom 13

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nr 2

Ograniczanie wyników

An assessment of hysteresis in studies on the hydraulic conductivity of peat soils

Verification of the Van Genuchten method of determination of the hydraulic conductivity of peat soils

Enzyme activity in forest peat soils

Vertical and horizontal permeability measurements in organic soils

Changes in the hydrophysical properties of peat soils under anthropogenic evolution

Dynamics of organic matter in peat soil under the conditions of sand-mix culture during 15 years

The influence of the moorshing process of peats on changes of their water capacity caused by thermal drying

Phosphate and ammonium concentrations in groundwater from peat soils in relation to the water table

Methanotrophs responsible for methane oxidation in natural peats from Polesie Lubelskie Region

Derivation of consolidation partial differential equations with non-linear flow characteristics on organic soil example