Effects of salinity and water content on apparent conductivity in an alluvial setting in the Canadian Prairies

2021 ◽  
Vol 80 (3) ◽  
Author(s):  
Jerrold W. Rentz ◽  
Ramanathan Sri Ranjan ◽  
Ian J. Ferguson ◽  
Hartmut M. Holländer
Keyword(s):  
Water Content ◽  
Canadian Prairies ◽  
Apparent Conductivity

WATER RETENTION EQUATIONS AND THEIR RELATIONSHIP TO SOIL ORGANIC MATTER AND PARTICLE SIZE DISTRIBUTION FOR DISTURBED SAMPLES

1983 ◽  
Vol 63 (2) ◽  
pp. 291-302 ◽  
Author(s):  
R. DE JONG ◽  
C. A. CAMPBELL ◽  
W. NICHOLAICHUK
Keyword(s):  
Organic Matter ◽  
Water Content ◽  
Soil Water ◽  
Water Retention ◽  
Water Retention Curve ◽  
Organic Carbon Content ◽  
Soil Water Retention ◽  
Canadian Prairies ◽  
Functional Relationships ◽  
Straight Line

Functional relationships between soil water content and water suction were examined and related to textural and organic carbon content data. Soil water retention curves between 5 and 10 000 kPa were determined on disturbed samples of 18 soils representing various soil Great Groups in the Canadian prairies. The best fit was obtained with a two-straight-line regression model. Correlation and regression analysis showed that texture was the main soil property influencing the shape and position of the water retention curve. Organic matter influenced primarily the water content at which a break in the curve occurred. Soil zone and cultivation history had little effect on water retention. Key words: Water retention, texture, organic matter, two-straight-line regression

Improvements to the accuracy of modelled soil water content from the Second Generation Prairie Agrometeorological Model

2010 ◽  
Vol 90 (3) ◽  
pp. 523-526 ◽  
Author(s):  
M. Gervais ◽  
P. Bullock ◽  
M. Mkhabela ◽  
G. Finlay ◽  
R. Raddatz
Keyword(s):  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Second Generation ◽  
Regional Scale ◽  
Canadian Prairies ◽  
Growing Seasons ◽  
Crop Development ◽  
Plant Available Water ◽  
Water Values

The direct measurement of soil water on a regional scale is often not practical due to large instrumental and labour requirements. Alternatively, soil water estimates can be derived using models. The Second Generation Prairie Agrometeorological Model (PAMII) models soil water, crop development and evapotranspiration (ET) in order to derive an estimate of crop water use. The objective of this study was to validate, and if necessary modify, the soil water component of PAMII using weather and soil water data collected from several spring wheat trials in Saskatchewan and Manitoba during the 2003 though 2006 growing seasons. Comparison of modelled and measured soil water values yielded a RMSE of 62 mm. For most site-years, PAMII overestimated soil water during the second half of the growing season, which was caused by an increase in modelled canopy resistance (rc) before the crop experienced water stress. The rc function was thus modified so that rc would not increase until the soil water content was < 0.5 of plant available water. Overall this modification reduced the RMSE from 62 to 56 mm. In addition, modelled soil water was underestimated during periods that experienced consecutive days of precipitation. This was because the model stopped infiltration when the top-zone reached saturation. When modified to allow infiltration to continue independent of the top-zone’s water content, the RMSE was further reduced to 53 mm. Overall, both modifications reduced the RMSE of modelled soil water by 9 mm, and this reduction was highly significant (P < 0.01). Key words: Prairie Agrometeorological Model (PAMII), soil water modelling, evapotranspiration, Canadian prairies

Coupling of dielectric mixing models with full-wave ground-penetrating radar signal inversion for sandy-soil-moisture estimation

Geophysics ◽  
2012 ◽  
Vol 77 (3) ◽  
pp. H33-H44 ◽  
Author(s):  
Anh Phuong Tran ◽  
Mohammad Reza Mahmoudzadeh Ardekani ◽  
Sébastien Lambot
Keyword(s):  
Soil Moisture ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Sandy Soil ◽  
Ground Penetrating Radar ◽  
Mixing Models ◽  
Apparent Conductivity ◽  
Full Wave ◽  
Ground Penetrating

We coupled dielectric mixing models with a full-wave ground-penetrating-radar (GPR) model to estimate the soil water content by inversion. Two mixing models were taken into account in this study, namely, a power law model and the Wang and Schmugge model. With this combination, we could account for the frequency dependence of the dielectric permittivity and apparent conductivity in the inverse algorithm and directly estimate the soil water content without using an empirical petrophysical formula or a priori knowledge on soil porosity. The approach was validated by a series of experiments with sandy soil in controlled laboratory conditions. The results showed that the performance of our approach is better than the common approach, which assumes a linear dependence of apparent conductivity on frequency and uses Topp’s equation to transform permittivity to water content. GPR data were perfectly reproduced in the time and frequency domains, leading to very accurate water-content estimates with an average absolute error of less than [Formula: see text]. However, the accuracy was reduced as the water content increased. Sensitivity analysis indicated that the Green’s function was most sensitive to the water content and sand-layer thickness but much less so with DC conductivity. The results also revealed that as the frequency increased, although the permittivity was nearly constant, the apparent electrical conductivity and the attenuation increased remarkably, especially for wet sands due to dielectric losses. The successful validation of the proposed approach opens a promising avenue of development to use dielectric mixing models for soil-moisture mapping from GPR measurements.

ESTIMATES OF SEEDING DATES OF SPRING WHEAT ON THE CANADIAN PRAIRIES FROM CLIMATE DATA

1988 ◽  
Vol 68 (2) ◽  
pp. 513-517 ◽  
Author(s):  
A. BOOTSMA ◽  
R. DE JONG
Keyword(s):  
Linear Regression ◽  
Water Content ◽  
Soil Water ◽  
Soil Water Content ◽  
Spring Wheat ◽  
Correlation Coefficients ◽  
Standard Errors ◽  
Climate Data ◽  
Canadian Prairies ◽  
Seeding Date

Estimates of seeding dates of spring wheat based on climatic criteria at selected prairie locations were compared with observed dates for corresponding crop districts using linear regression and correlation analyses. Correlation coefficients ranged from 0.11 to 0.76 and standard errors of estimates of regression from 3.9 to 8.5 d. Average estimated seeding dates were consistently earlier by about 3–8 d than average observed values reported for periods ranging from 24 to 33 yr.Key words: Correlation, regression, seeding date criteria, soil water content

Characterization of frozen hydrated biological specimens by low-loss EELS

1992 ◽  
Vol 50 (2) ◽  
pp. 1572-1573
Author(s):  
Songquan Sun ◽  
Richard D. Leapman
Keyword(s):  
Water Content ◽  
Direct Method ◽  
Internal Standard ◽  
Dry Weight ◽  
Dark Field ◽  
Protein Solutions ◽  
Subcellular Compartment ◽  
Differential Shrinkage ◽  
Electron Energy Loss

Analyses of ultrathin cryosections are generally performed after freeze-drying because the presence of water renders the specimens highly susceptible to radiation damage. The water content of a subcellular compartment is an important quantity that must be known, for example, to convert the dry weight concentrations of ions to the physiologically more relevant molar concentrations. Water content can be determined indirectly from dark-field mass measurements provided that there is no differential shrinkage between compartments and that there exists a suitable internal standard. The potential advantage of a more direct method for measuring water has led us to explore the use of electron energy loss spectroscopy (EELS) for characterizing biological specimens in their frozen hydrated state.We have obtained preliminary EELS measurements from pure amorphous ice and from cryosectioned frozen protein solutions. The specimens were cryotransfered into a VG-HB501 field-emission STEM equipped with a 666 Gatan parallel-detection spectrometer and analyzed at approximately −160 C.

STEM measurement of subcellular water distributions

1993 ◽  
Vol 51 ◽  
pp. 568-569
Author(s):  
R.D. Leapman ◽  
S.Q. Sun ◽  
S-L. Shi ◽  
R.A. Buchanan ◽  
S.B. Andrews
Keyword(s):  
Water Content ◽  
Internal Standard ◽  
Dry Weight ◽  
Dry Mass ◽  
Scanning Transmission Electron Microscope ◽  
Dark Field ◽  
Bulk Water ◽  
Inelastic Electron ◽  
Scanning Transmission ◽  
Annular Dark Field

Recent advances in rapid-freezing and cryosectioning techniques coupled with use of the quantitative signals available in the scanning transmission electron microscope (STEM) can provide us with new methods for determining the water distributions of subcellular compartments. The water content is an important physiological quantity that reflects how fluid and electrolytes are regulated in the cell; it is also required to convert dry weight concentrations of ions obtained from x-ray microanalysis into the more relevant molar ionic concentrations. Here we compare the information about water concentrations from both elastic (annular dark-field) and inelastic (electron energy loss) scattering measurements.In order to utilize the elastic signal it is first necessary to increase contrast by removing the water from the cryosection. After dehydration the tissue can be digitally imaged under low-dose conditions, in the same way that STEM mass mapping of macromolecules is performed. The resulting pixel intensities are then converted into dry mass fractions by using an internal standard, e.g., the mean intensity of the whole image may be taken as representative of the bulk water content of the tissue.

EFFECT OF WATER CONTENT ON PROPERTIES OF Na2O, 3SiO2 GLASSES

1982 ◽  
Vol 43 (C9) ◽  
pp. C9-455-C9-458 ◽  
Author(s):  
M. Takata ◽  
M. Tomozawa ◽  
J. Acocella ◽  
J. Molinelli ◽  
C. Y. Erwin ◽  
...  
Keyword(s):  
Water Content ◽  
Effect Of Water

ANALISIS FISIKA KIMIA DARI KERANG DARA (Anadara granosa) YANG BERASAL DARI KAYUTANYO KAB. BANGGAI The Analysis of physical chemical from dara shells (Anadara granosa) origin from Kayutanyo, Kab.Banggai

2018 ◽  
Vol 2 (2) ◽  
Author(s):  
SULASMI ANGGO
Keyword(s):  
Protein Content ◽  
Water Content ◽  
Water Solubility ◽  
Gravimetric Method ◽  
Fat Content ◽  
Carbohydrate Content ◽  
Dust Content ◽  
Total Dust ◽  
Physical Chemical ◽  
Anadara Granosa

The Analysis of physical chemical from dara shells (Anadara granosa) origin from Kayutanyo, kab. Banggai, has been conducted.Dara shell meat is sleaned and dried and after that powered with blender. Determine % rendement, water bonding capacity and index water solubility with Anderson method, coarse fat content with gravimetric method and carbohydrate method with “bye difference” decrease method.The result of analysis showed rendement value is 24,35%, water bonding capacity is 1,6248 gram/ml, index water solubility is 0,202 gram/ml, water content is 79,0045%, total dust content is 1,072%, coarse protein content is 2,25%, coarse fat content is 8,47%, carbohydrate content is 9,2035%. Keyword : Dara shells, (Anadara granosa), analysis physical chemical

Sign in / Sign up

Export Citation Format

Share Document