RELATIONSHIPS OF ELECTRICAL CONDUCTIVITY WITH TOTAL DISSOLVED SALTS AND CATION CONCENTRATION OF SULFATE-DOMINANT SOIL EXTRACTS

1983 ◽  
Vol 63 (1) ◽  
pp. 79-86 ◽  
Author(s):  
C. CHANG ◽  
T. G. SOMMERFELDT ◽  
J. M. CAREFOOT ◽  
G. B. SCHAALJE
Keyword(s):  
Electrical Conductivity ◽  
Extraction Methods ◽  
Accurate Estimation ◽  
Regression Equations ◽  
Soluble Salts ◽  
Soil Extracts ◽  
Cation Concentration ◽  
Saturation Extract ◽  
Dominant Soil ◽  
Dissolved Salts

Simple equations for accurate estimation of total dissolved salts (TDS) and cation concentration (CΣ) from electrical conductivity (EC) measurements (ranging from 0 to 16 mS/cm) were developed for sulfate-rich soils in southern Alberta. Soil extracts were obtained by the saturation extract method from 879 samples. From 260 of these samples, the 1:10 extraction method was also used. Electrical conductivity and TDS in the solution (by summation of the ions and/or by evaporation) were determined. Several regression equations were fitted. The following equation is recommended for estimating TDS (in mg/L):[Formula: see text]For estimating the cation concentration (CΣ in meq/L), the equation[Formula: see text]is recommended. Total soluble salts determined by summation of ions was about 16% less than that by the evaporation method. The amount of salts extracted from the soil was greater with 1:10 extraction than with the saturation extract method, but considerable discrepancy was found between the two extraction methods. Key words: Electrical conductivity, soluble salts, soluble cations, total dissolved salts, sulfate-dominant salts, soil extracts

scholarly journals Chemical properties of an Oxisol after gypsum application

2016 ◽  
Vol 37 (5) ◽  
pp. 3027
Author(s):  
Victor Roncaratti de Moraes ◽  
Thadeu Rodrigues de Melo ◽  
Osmar Rodrigues Brito
Keyword(s):  
Electrical Conductivity ◽  
Soil Amendment ◽  
Chemical Properties ◽  
Vacuum Extraction ◽  
Regression Equations ◽  
Soil Columns ◽  
High Solubility ◽  
Saturation Extract ◽  
Significant Difference ◽  
Gypsum Application

Gypsum utilization is a critical practice in agriculture because of the high solubility and consequent relative neutralization of subsurface toxic aluminum. However, it has been observed that in most cases, gypsum is being randomly utilized without scientifically established parameters or even the need to use it as a soil amendment at all. The objective of this study was to evaluate the chemical composition and electrical conductivity of an Oxisol’s saturation extract under different gypsum doses (0, 1.0, 2.0, 4.0, and 8.0 Mg ha-1). This experiment was conducted in a greenhouse environment. Soil columns (V = 1.57 dm3) were filled with sifted (2 mm) soil collected from the upper layer (0-20 cm). The experimental design adopted was completely randomized with five repetitions. The treatments consisted of a 5 × 2 factorial through five gypsum doses (0.0, 1.0, 2.0, 4.0, and 8.0 Mg ha-1 of gypsum consisting of 224.1 g kg-1 S, 314.8 g kg-1 CaO, and 7 g kg-1 P2O5) and two depth evaluations (0-10 and 10-20 cm). After the treatments, soil from both 0-10 cm and 10-20 cm layers was removed from the columns, sifted once (2 mm), and subjected to vacuum extraction to assess the saturation extract. The data acquired was processed and submitted to variance analysis (when due) and adjusted to regression equations when statistically relevant. Significant increases were observed for Ca, Mg, K, P, and S, although Al, Si, and pH presented no statistically significant difference. The electrical conductivity value of this soil in particular is directly related to the gypsum dose.

Characterization of dissolved organic matter (DOM) extracted from soils by hot water percolation (HWP)

2010 ◽  
Vol 59 (1) ◽  
pp. 99-108 ◽  
Author(s):  
M. Takács ◽  
Gy. Füleky
Keyword(s):  
Organic Matter ◽  
Humic Acid ◽  
Natural Organic Matter ◽  
Extraction Methods ◽  
Soil Samples ◽  
Hot Water ◽  
Soil Extracts ◽  
Water Percolation ◽  
Soil Humic Acid

The Hot Water Percolation (HWP) technique for preparing soil extracts has several advantages: it is easily carried out, fast, and several parameters can be measured from the same solution. The object of this study was to examine the possible use of HWP extracts for the characterization of soil organic matter. The HPLC-SEC chromatograms, UV-VIS and fluorescence properties of the HWP extracts were studied and the results were compared with those of the International Humic Substances Society (IHSS) Soil Humic Acid (HA), IHSS Soil Fulvic Acid (FA) and IHSS Suwannee Natural Organic Matter (NOM) standards as well as their HA counterparts isolated by traditional extraction methods from the original soil samples. The DOM of the HWP solution is probably a mixture of organic materials, which have some characteristics similar to the Soil FA fractions and NOM. The HWP extracted organic material can be studied and characterized using simple techniques, like UV-VIS and fluorescence spectroscopy.

Estimation of Mortality Risk in Chronically Ventilated Infants With Bronchopulmonary Dysplasia

PEDIATRICS ◽  
1991 ◽  
Vol 88 (6) ◽  
pp. 1153-1160 ◽  
Author(s):  
Debora W. Overstreet ◽  
J. Craig Jackson ◽  
Gerald van Belle ◽  
William E. Truog
Keyword(s):  
Mechanical Ventilation ◽  
Bronchopulmonary Dysplasia ◽  
Airway Pressure ◽  
Life Support ◽  
Water Pressure ◽  
Accurate Estimation ◽  
Regression Equations ◽  
Bacterial Sepsis ◽  
Mean Airway Pressure ◽  
Predictors Of Mortality

Bronchopulmonary dysplasia is a chronic, sometimes fatal lung disease, which primarily affects premature infants and often leads to a dependence on mechanical ventilation lasting many months. To identify prognostic factors of mortality at 1 and 2 months of age, the authors reviewed the medical records of the 144 neonates admitted to two neonatal intensive care units in Seattle from January 1, 1986, through December 31, 1988, who required mechanical ventilation throughout the first month of life. Likely predictors of mortality were tested by logistic regression analysis. The calculated mean airway pressure at 30 days of age (MAP30) and the diagnosis of bacterial sepsis at any time during the first month of life (Bact0-30) were statistically significant predictors of mortality (P < .001 and P = .018, respectively) and had the lowest deviance in the regression model. The probability of mortality was estimated by 1/(1 + e-x, where x = -6.510 + 0.4588 (MAP30) + 1.475 (Bact0-30), and where MAP30 is expressed as centimeters of water pressure (1 cm H2O = 0.0978 kPa) and the presence or absence of bacteremia is 1 and 0, respectively. The records of the 57 infants who still required mechanical ventilation at 60 days of age were reanalyzed with clinical data available during the first 2 months of life. Mean airway pressure (MAP60) and the fraction of inspired oxygen (F60) at 60 days of age combined to form the best predictors of mortality, where x = -7.668 + 0.2940 (MAP60) + 5.935 (F60). The occurrence of bacterial sepsis during the first 2 months of life, the degree of hypochloremia, and the duration of chronic sedative use were also significant predictors of survival, even controlling of MAP60 and F60. These regression equations allow more accurate estimation of the likelihood of survival for chronically ventilated infants and may facilitate decisions regarding withdrawal or continuation of life support.

scholarly journals Concentration of injetion solution and its effects on soil and on yield of fertirrigated banana cv. Terra Maranhão

2014 ◽  
Vol 34 (6) ◽  
pp. 1104-1113 ◽  
Author(s):  
Eugênio F. Coelho ◽  
Torquato M. de Andrade Neto ◽  
Damiana L. Barros
Keyword(s):  
Electrical Conductivity ◽  
Soil Solution ◽  
Irrigation Water ◽  
Urea Concentration ◽  
Injection Solution ◽  
Combined Application ◽  
Saturation Extract ◽  
Randomized Design ◽  
Completely Randomized Design ◽  
Micro Irrigation

The Fertigation is the combined application of water and nutrients to a crop. It can be adapted to all types of agricultural crops. The objective of this study was to evaluate the effect of urea concentration in irrigation water on electrical conductivity of the soil solution and saturation extract along the first cycle of banana cv. Terra Maranhão. The experiment followed a completely randomized design with six treatments and ten replications. Treatments regarded for using three urea concentrations (1.0; 2.5 and 4.0 g L-1) in irrigation water applied by two micro irrigation systems (microsprinkler and drip). Results showed that there was a linear elevation of electrical conductivity of saturation extract and soil solution with the increase on concentration of urea in the injection solution. Urea should be used under concentrations up to 2.5 g L-1 in irrigation water without causing increase on electric conductivity of soil solution and saturation extract, considering 1.1 dS m-1 as the tolerated value for the crop. Nitrate in the soil solution increased significantly with the increase of urea concentration in the injection solution. The maximum concentration of nitrate in the soil occurred for 4,0 g L-1 concentration of the injection solution.

scholarly journals Surface irrigation with saline water on a heavy clay soil in the Medjerda Valley, Tunisia.

1967 ◽  
Vol 15 (4) ◽  
pp. 281-303
Author(s):  
J.A. Van 't Leven ◽  
M.A. Haddad
Keyword(s):  
Electrical Conductivity ◽  
Clay Soil ◽  
Saline Water ◽  
Surface Irrigation ◽  
Soil Extracts ◽  
Fallow Period ◽  
Salinity Effects ◽  
Heavy Clay ◽  
Winter Crops ◽  
Resting Period

On a clay soil rich in lime, with drain spacings of 30 and 60 m, one section (A) after four crops of artichokes over a two-year period, with fairly intensive irrigation with saline water (approx 700 mm annually) showed no harmful salinity effects; in the upper 120 cm the electrical conductivity of soil extracts (EC) seldom exceeded five. On section B, with well-distributed irrigation, which was not intensive except for tomatoes in one summer, salinity was fairly uniform in the profile (EC 4-6). In section C, under continuous lucerne and with 1000-1200 mm water annually, salinity increased, especially with depth, and a fallow period was needed. In section D, under four artichoke crops followed by maize, with more intensive irrigation than in A and B, EC of the 80-120 cm layer was 7-8, and maize growth was retarded slightly. In addition to fallowing, the inclusion in rotations of winter crops and of perennials with a resting period in summer, e.g. artichokes, is recommended. A drain spacing of 60 m was adequate. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Liquid Chromatographic Method for Determination of Extractable Nitroaromatic and Nitramine Residues in Soil

1989 ◽  
Vol 72 (6) ◽  
pp. 890-899 ◽  
Author(s):  
Thomas F Jenkins ◽  
Mariannee Walsh ◽  
Patricia W Schumacher ◽  
Paul H Miyares ◽  
Christopher F Bauer ◽  
...  
Keyword(s):  
Contaminated Soils ◽  
Extraction Methods ◽  
Ease Of Use ◽  
Linear Calibration ◽  
Soil Extracts ◽  
Spiked Soil ◽  
Collaborative Test ◽  
Wide Range ◽  
Working Standards ◽  
Liquid Chromatographic

Abstract An analytical method was developed to determine the concentration of nitroaromatic and nitramine residues in soil. Air-dried soil samples are ground with a mortar and pestle and extracted with acetonitrile in an ultrasonic bath. A portion of extract is diluted with aqueous CaCh to flocculate suspended particles, filtered, and analyzed by liquid chromatography. The method provides linear calibration curves over a wide range of concentration. Detection limits ranged from 0.03 to 1.27 ng/g. Recovery of spiked analyte was better than 80% for all analytes tested. Each step in the analytical procedure was optimized using spiked and field-contaminated soils. This optimization included tests to (1) assess the effectiveness and kinetics associated with various extraction methods, solvents, and soil-to-solvent ratios; (2) compare separations achievable using various combinations of reverse-phase columns and eluants; (3) assess analyte recovery and ease of use for various procedures to remove particles from extracts; and (4) document stability of soil extracts and analytical stock and working standards. A ruggedness test and a preliminary assessment at 2 other laboratories indicated that the method was sufficiently rugged to justify a full-scale collaborative test. A comparison of extraction kinetics for spiked soil vs field-contaminated soil revealed very different kinetic behavior, indicating it is unwise to develop extraction procedures based solely on spiked soils.

scholarly journals SPATIAL CONTINUITY OF ELECTRICAL CONDUCTIVITY, SOIL WATER CONTENT AND TEXTURE ON A CULTIVATED AREA WITH CANE SUGAR

2018 ◽  
Vol 31 (2) ◽  
pp. 434-445
Author(s):  
JUCICLÉIA SOARES DA SILVA ◽  
ÊNIO FARIAS DE FRANÇA E SILVA ◽  
GLÉCIO MACHADO SIQUEIRA ◽  
GERÔNIMO FERREIRA DA SILVA ◽  
DIEGO HENRIQUE SILVA DE SOUZA
Keyword(s):  
Electrical Conductivity ◽  
Spatial Variability ◽  
Water Content ◽  
Integrated Management ◽  
Soil Layer ◽  
Cane Sugar ◽  
Spatial Continuity ◽  
Sugarcane Crop ◽  
Saturation Extract ◽  
Apparent Electrical Conductivity

ABSTRACT Spatial variability of soil attributes affects crop development. Thus, information on its variability assists in soil and plant integrated management systems. The objective of this study was to assess the spatial variability of the soil apparent electrical conductivity (ECa), electrical conductivity of the saturation extract (ECse), water content in the soil (θ) and soil texture (clay, silt and sand) of a sugarcane crop area in the State of Pernambuco, Brazil. The study area had about 6.5 ha and its soil was classified as orthic Humiluvic Spodosol. Ninety soil samples were randomly collected and evaluated. The attributes assessed were soil apparent electrical conductivity (ECa) measured by electromagnetic induction with vertical dipole (ECa-V) in the soil layer 0.0.4 and horizontal dipole (ECa-H) in the soil layer 0.0-1.5 m; and ECse, θ and texture in the soil layers 0.0-0.2 m and 0.2-0.4 m. Spatial variability of the ECa was affected by the area relief, and had no direct correlation with the electrical conductivity of the saturation extract (ECse). The results showed overestimated mean frequency distribution, with means distant from the mode and median. The area relief affected the spatial variability maps of ECa-V, ECa-H, ECse and θ, however, the correlation matrix did not show a well-defined cause-and-effect relationship. Spatial variability of texture attributes (clay, site and sand) was high, presenting pure nugget effect.

Studies on recycling spent compost for mushroom cultivation

1976 ◽  
Vol 27 (6) ◽  
pp. 857 ◽  
Author(s):  
NG Nair
Keyword(s):  
Electrical Conductivity ◽  
Calcium Chloride ◽  
Calcium Nitrate ◽  
Peat Moss ◽  
Mushroom Cultivation ◽  
Soluble Salts ◽  
Rice Hulls ◽  
Mushroom Production ◽  
Commercial Cultivation ◽  
Casing Layer

Natural weathering of spent compost for 2 years resulted in a lowering of electrical conductivity which enabled it to be used as a casing material in mushroom cultivation. Spent compost and peat moss had different optima of electrical conductivity values for normal mushroom production. Relatively high levels of soluble salts such as calcium nitrate and calcium chloride reduced the yield of mushrooms. The addition of rice hulls and peat moss to spent compost overcame the effect of sealing caused by watering. These amendments improved aeration of the casing layer and increased the number of pseudomonads. Pasteurized, spent compost, aged for 2 years, at a moisture level of 65% saturation, was shown to be a suitable casing material for obtaining relatively good yields of mushrooms. It is suggested that this material may find an application in commercial cultivation of mushrooms.

scholarly journals The Correlation and Regression Analysis of Physicochemical Parameters of River Water for the Evaluation of Percentage Contribution to Electrical Conductivity

2018 ◽  
Vol 2018 ◽  
pp. 1-9 ◽  
Author(s):  
Arun Kumar Shrestha ◽  
Nabin Basnet
Keyword(s):  
Electrical Conductivity ◽  
Correlation Coefficients ◽  
Quality Standards ◽  
Total Alkalinity ◽  
Total Hardness ◽  
Regression Equations ◽  
Water Quality Standards ◽  
Percentage Contribution ◽  
Correlation And Regression Analysis ◽  
Standard Procedures

Ten different water samples were collected from Ratuwa River and its tributaries. The laboratory test was carried out by standard procedures (APHA methods), and the measured values were compared with the Nepal standard recommended by Nepal Drinking Water Quality Standards (NDWQS). Statistical analysis also had been used to calculate the correlation coefficients and to plot the regression equations of various parameters with electrical conductivity. The aim of the study was to identify the parameters that affect the electrical conductivity and evaluate the percentage contribution of these parameters. The correlation matrix shows that color, total dissolved solids (TDS), chloride (Cl), fluoride (F), total phosphorus (TP), total alkalinity (TA), calcium (Ca), magnesium (Mg), sodium (Na), and dissolved oxygen (DO) have a significant effect on the electrical conductivity (EC). Among these parameters, TDS has the highest contribution (39.65%) followed by total alkalinity (23.5%), total hardness (19.9%), chlorine (6.5%), and calcium (5.5%) ions, respectively. However, color, TP, fluoride, and DO have almost 1.45% contribution to the electrical conductivity.

Electrical conductivity and electrolyte distribution in a secreting salivary gland

1961 ◽  
Vol 201 (6) ◽  
pp. 1002-1006 ◽  
Author(s):  
A. Van Harreveld ◽  
R. L. Potter ◽  
L. J. Sloss
Keyword(s):  
Electrical Conductivity ◽  
Salivary Gland ◽  
Submaxillary Gland ◽  
Chloride Content ◽  
Histochemical Method ◽  
Total Solids ◽  
Cation Concentration

During the first 4–7 min of pilocarpine-induced secretion the submaxillary gland lost a large part of its electrical conductivity (a mean loss of 40% in 8 experiments). In preparations of control and experimental glands treated with a histochemical method for chloride a marked loss of fluid and electrolytes from the intertubular spaces could be demonstrated during this period. This loss of extracellular electrolytes provides an explanation for the drop in conductivity of the gland. A comparison of control and experimental glands showed that during the first minutes of secretion the gland lost water and total solids, decreased in potassium and chloride content, gained sodium, and increased slightly in total cation concentration.

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