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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

Comment on water potential definition

100%

Sobczuk H. A.

Zeszyty Problemowe Postępów Nauk Rolniczych

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1996

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tom 436

The definition of soil water potential is based on the chemical potential of homogeneous medium. The assumption of homogeneity causes many difficulties to arise when such a definition is used for the description of highly heterogeneous soil medium. Another aspect discussed here is the basic of division of a soil water potential onto additive parts (pressure, gravitational, thermal etc.). It has been shown here that this division can be done when only one parameter of state changes, otherwise it is only approximation with possibly high error.

3

Use of porous tubes for measuring water extraction by roots and simultaneous maintaining of soil water potential in growth chamber experiments

75%

Nosalewicz A., Iijima M., Lipiec J., Krol A.

Acta Agrophysica

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2011

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tom 18

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nr 2[193]

The efficiency of a system based on porous tubes in maintaining soil water potential during water extraction by plants in growth chamber experiment was evaluated. The effect of porous tubes area, soil type and density on water flow through porous tubes as induced by various water potentials was evaluated. The rate of change of soil water potential in response to pressure change depends strongly on the area of ceramic tubes per soil volume. If rapid changes or precise control of soil water potential are needed, the area of ceramic tubes per soil volume should be large. Experiments in which porous tubes are used for maintaining water potential should reach a compromise between plant water demands and permissible disturbance caused by the presence of porous tubes in the soil environment.

4

Modelling of leaf temperature and transpiration as a function of soil water potential

75%

Olszta W., Wiszniewska-Oraczewska I.

Zeszyty Problemowe Postępów Nauk Rolniczych

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1996

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tom 436

The empirical verification of TRANSP and TERGRA models was the main purpose of conducted researches. The models introduced in this paper describe the diurnal patterns of leaf temperature and transpiration when grass is exposed to increasing water deficit under field conditions. The difference simulation results of leaf water potential, leaf temperature and transpiration flux for low and high soil water potential rates and for different meteorological conditions show that these models need more research and measurements for a better identification of function aqd parameters especially for wet conditions, making these models more useful for irrigation scheduling, using the remote sensing techniques.

5

Different patterns of changes in foliar carbon isotope composition along altitude

75%

He Z., Zhan S., Wang W., Hu L., Wu S.

Polish Journal of Ecology

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2017

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tom 65

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nr 2

Three types of alpine plant species,Carex montis-everestii,Quercus aquifolioidesandStipa capillacea, along an altitudinal gradient of 3005–5025 m on the Tibetan Plateau, were chosen to test the generality of the hypothesis that foliar carbon isotope composition (δ¹³C) of C3 plants increases significantly with altitude and to determine climate drivers shaping its altitudinal pattern. Temperature and relative humidity showed significantly negative correlations with altitude; however, precipitation and soil water potential remained unchanged with altitude. Foliar δ¹³C of C. montis-everestii,Q. aquifolioides,S. capillaceaalone or combined together did not significantly increase with altitude, which does not support the leading hypothesis of increased foliar δ¹³C with altitude. There was no difference in foliar δ¹³C among all three species. Multi-factor correlation analyses showed that temperature, precipitation and relative humidity alone did not affect foliar δ¹³C ofC. montis-everestiiandS. capillacea, but conferred significant effects on foliar δ¹³C of Q. aquifolioides.

6

Comparison of correlation models for the estimation of the water retention characteristics of soil

75%

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

International Agrophysics

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2002

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tom 16

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nr 1

7

Mycorrhizal status of Scots pine Pinus sylvestris L. seedlings grown in watered and non-watered nursery condition

63%

Hilszczanska D.

Dendrobiology

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2004

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tom 52

23-28

This study describes the effect of watering on the mycorrhizal development and growth of Scots pine seedlings in a bare root nursery. Seedlings of Scots pine, grown under nursery conditions on natural soil (loamy sand) and soil + litter, were subjected to two different watering regimes for five months. During this time, measurements of soil water potential were made. Seedlings grown in natural soil and subjected to drought conditions were of significantly greater shoot height and volume and they had one mycorrhizal morphotype more than watered seedlings. However, irrigated seedlings subjected to excessive watering possessed greater mycorrhizal colonization: 46% on natural soil and 72% on soil + litter, while non-irrigated seedlings had 36% and 67% levels of mycorrhizal colonization, respectively.

8

The model investigation of soil water content and soil water potential impact on radiation temperature of meadow plant cover

63%

Mazurek W., Walczak R. T., Sobczuk H. A., Baranowski P.

Zeszyty Problemowe Postępów Nauk Rolniczych

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1996

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tom 436

The purpose of the study was to find the relation between soil water condition and radiation temperature of meadow vegetation. During the experiment, performed in precisely controlled laboratory conditions, AGA Thermovision System 680 was used for measuring the radiation temperature. The natural meadow plant cover growing on mineral and organic soils taken into the pots was the object of the investigation. The watering of pots was performed in such a way that to get 8 different soil moisture levels. There exist boundary values of soil water content below which the increase of radiation temperature begins. They are 45 % for the organic soil and 15 % for mineral soil. However these values of soil water content correspond to the same soil water potential of about 15 bars. The increase of radiation temperature indicates the limit of the accessibility of soil water for the root system rather than the concentration of water in the soil.

9

Wplyw geometrii probki na retencje wodna gleby

51%

Czachor H.

Acta Agrophysica

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2001

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tom 53

81-91

10

Psychrometryczny pomiar potencjalu wody w materialach rolniczych

51%

Skierucha W.

Acta Agrophysica

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2002

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tom 72

117-124

11

Interrelations between DNA concentration and physicochemical parameters in the loess soil profile

51%

Wolinska A., Stepniewska Z., Woloszyn A., Rzewuska M.

Acta Agrophysica

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2012

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tom 19

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nr 2

The purpose of presented study was determination of the impact of selected physicochemical parameters, strongly influencing the soil biological life: water potential (pF), oxygen availability for microorganisms (ODR), redox potential (Eh), content of Mg, Ca and total organic carbon (TOC) on soil DNA concentration. Undisturbed loess soil material was taken to metal cylin-ders (100 cm3) from four depths (0-20; 20-40; 40-60 and 60-80 cm), what make possibility for description of DNA content and its distribution in the whole soil profile. Our results revealed signif-icant (p<0.05) positive relationships between soil DNA content and measured values of ODR (r = 0.94***), Eh (r = 0.52**) and TOC (r = 0.98***), what were confirmed by high values of correla-tion coefficients (r). Whereas, significant negative interrelationships between soil DNA and pF (r = –0.57*) or Mg content (r = –0.79***) were determined. However, in the current experiment condi-tions, we did not found significant correlation between Ca presence and DNA content (p>0.05). Significant (p<0.05) decrease of DNA concentration by 62.8% with an increase of soil depth was noted, what was undoubtedly connected with spatial distribution of microorganisms in the soil profile and its likes for surface layers colonization.

12

Wlasciwosci wodne gleb organicznych Doliny Grojeckiej w sasiedztwie projektowanej odkrywki wegla brumatnego 'Drzewce'

38%

Owczarzak W., Mocek A., Gajewski P.

Acta Agrophysica

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2003

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tom 01

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nr 4[89]

711-720

13

Metodyczne zagadnienia monitoringu statusu wody w wybranych materialach biologicznych

32%

Malicki M. A.

Acta Agrophysica

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1999

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tom 19

1-108

Methodical questions of monitoring of water status in soil, cereals grain and wood are discused ( where monitoring is understood as registration of time and spatial variability of selected properties). Amount of viariables which is necessary in order to determine water status depends on the complexion of the considered phenomena and is, so far, the matter of arbitrary choice. In most practical cases the water status is expressed only by moisture of the considered material ( like the building timber). In practical terms, two variables suffice to express water status in cereal grain: moisture and temperature. To describe water status in the soil not less then five variables are needed: amount of water (the soil moisture) soil water potential, salinity, oxygenation and temperature. The only sensors that can be integrated in modern data acquisition system must be read electrically. Therefore electroresistance and electrocapacitance methods were considered. Dielectric sensors were recognized as the proper choice.Soil is a complex material having instable characteristics. For this reason it is the most difficult task to monitor soil water status, particularly to determine the soil moisture. Therefore it has been assumed that measuring methods verified for the soil will be also suitable for other, less complex materials. Thus, monitoring of soil water status was mainly discussed. Special attention was focused to the time domain reflectometry, TDR, as the semi selective method for the soil moisture and salinity determination.

Ograniczanie wyników

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

Comment on water potential definition

Use of porous tubes for measuring water extraction by roots and simultaneous maintaining of soil water potential in growth chamber experiments

Modelling of leaf temperature and transpiration as a function of soil water potential

Different patterns of changes in foliar carbon isotope composition along altitude

Comparison of correlation models for the estimation of the water retention characteristics of soil

Mycorrhizal status of Scots pine Pinus sylvestris L. seedlings grown in watered and non-watered nursery condition

The model investigation of soil water content and soil water potential impact on radiation temperature of meadow plant cover

Wplyw geometrii probki na retencje wodna gleby

Psychrometryczny pomiar potencjalu wody w materialach rolniczych

Interrelations between DNA concentration and physicochemical parameters in the loess soil profile

Wlasciwosci wodne gleb organicznych Doliny Grojeckiej w sasiedztwie projektowanej odkrywki wegla brumatnego 'Drzewce'

Metodyczne zagadnienia monitoringu statusu wody w wybranych materialach biologicznych