The chemistry of saturation extracts of Solonetzic and associated soils

1992 ◽  
Vol 72 (1) ◽  
pp. 43-56 ◽  
Author(s):  
R. J. Heck ◽  
A. R. Mermut
Keyword(s):  
Chemical Evolution ◽  
Soil Development ◽  
Exchangeable Sodium ◽  
Saturation Indices ◽  
Soil Extracts ◽  
Closed Basin ◽  
Cation Concentration ◽  
Exchange Constants ◽  
Salt Affected Soils ◽  
Exchange Selectivity

Cation speciation in soil extracts from a catenary sequence of salt-affected soils was studied to understand the chemical evolution of Solonetzic soils in a closed basin. Major changes in cation speciation were found to occur at each phase of soil development. The proportion of thermodynamically active cations was greater in the extracts from the more leached profiles. Saturation indices suggested that the extracts achieved equilibrium with calcite and gypsum, when present in the soil, within 24 h. Accumulations and/or losses of gypsum and calcite from saline layers indicate that there are ongoing changes in their stability. The ratio of Ca2+/Mg2+ suggested a possible equilibrium with Mg-bearing calcites; conditions existed in certain horizons for the formation of this group of minerals. Correlations between exchangeable sodium ratios and sodium adsorption ratios calculated using cation concentration and activity were similar; however, using activities to determine the exchange constants resulted in significant differences.Key words: Cation speciation, saturation indices, cation adsorption, exchange selectivity constants, Solonetzic soils

AN INVESTIGATION ON THE DEPENDENCE OF THE GAPON COEFFICIENT ON EXCHANGEABLE SODIUM BY THREE LINEAR TRANSFORMATIONS

1988 ◽  
Vol 68 (4) ◽  
pp. 813-820
Author(s):  
V. P. EVANGELOU ◽  
F. J. COALE
Keyword(s):  
Clay Minerals ◽  
Limited Range ◽  
Selectivity Coefficient ◽  
Sodium Adsorption Ratio ◽  
Exchangeable Sodium ◽  
Linear Transformations ◽  
Laboratory Staff ◽  
Soil Systems ◽  
Exchange Adsorption ◽  
Exchange Selectivity

Based on theorical considerations of ideal exchangers, the traditional Gapon exchange selectivity coefficient (KG) is generally not expected to remain constant for exchangeable sodium ratio (ESR) greater than 0.20. Therefore, the ESR-SAR (SAR=sodium adsorption ratio) relationship is only expected to be linear and predictable for this limited range of exchange sites. The purpose of this study is to demonstrate that for some soils and/or clay minerals, which are considered nonideal exchangers, the KG may remain constant for ESR values greater than 0.20. This information is important for the reclamation of sodic soil systems with ESR > 0.2 to near Na+ saturation. Experimental data in the literature is most often limited in the ESR range of 0 – 1. Experimental Na+-Ca2+ exchange data for each of a number of soils and clay minerals were plotted according to three linear transformations of the Gapon expression in order to determine if a particular soil or clay mineral exhibits a constant Gapon exchange selectivity coefficient (KG) for ESR values significantly greater than 0.20. The three linear transformations are represented by plots of (1) 1/ExNa vs. 1/SAR, (2) ExNa vs. ExNa/SAR and (3) SAR/ExNa vs. SAR (ExNa = exchangeable Na). From the three plots employed, the ExNa vs. ExNa/SAR and the SAR/ExNa vs. SAR were shown to be the most applicable in predicting a constant KG for ESR values greater than 0.20. It is also shown that some generally low CEC materials may exhibit a constant KG for ESR values significantly greater than 0.20. These data also infer that for a particular soil the linearity of the widely used ESR-SAR relationship introduced by the U.S. Salinity Laboratory Staff may not be limited to an ESR value of 0.20. Key words: Exchangeable sodium percentage, sodium adsorption ratio, thermodynamics of cation exchange, adsorption maxima, ion affinity constants.

Reclamation of salt-affected soils in the Goulburn Valley of Victoria

1983 ◽  
Vol 23 (123) ◽  
pp. 412 ◽  
Author(s):  
AH Mehanni ◽  
GE Bleasdale
Keyword(s):  
Crop Yields ◽  
Crop Productivity ◽  
Exchangeable Sodium ◽  
Saturation Extract ◽  
Heavy Soil ◽  
Added Benefit ◽  
Salt Affected Soils ◽  
Subsurface Drains ◽  
Reclamation Process ◽  
Yield Of Oats

A heavy soil (Goulburn loam) in the Goulburn Valley that was badly salinized was quickly reclaimed after control of the watertable to between 60 and 90 cm with subsurface drains. Within 16 months of installing slotted PVC drains 1 .5 m deep and 8.6 m apart, the electrical conductivity of a saturation extract decreased from 16.9 to 1 -9 mS/cm and crop yields increased substantially (oats from 1833 to 321 0 kg/ha, millet from 638 to 31 89 kg/ha). In addition, a white clover-based perennial pasture was established, which in the first season yielded 6985 kg/ha clover compared with 613 kg/ha in the absence of drains. The effects on the reclamation process and crop productivity of ripping the soil to 40 cm, applying gypsum at 10 t/ha, or a combination of both treatments were investigated. No soil treatment was effective without drainage due to the persistence of the shallow saline watertable. With drainage, gypsum applications decreased exchangeable sodium from 8.3 to 3.7% and increased hydraulic conductivity from 1 12 to 24.4 cm/d in the surface 15 cm. Gypsum also increased infiltration by 40%, leaching of chloride by 33% and yield of oats and clover by 44 and 29% respectively. Ripping either alone or combined with gypsum was of no added benefit

scholarly journals Occurrence of Soil Tumors Northeast of the Guánica Lagoon, Lajas Valley, P.R.

1969 ◽  
Vol 43 (2) ◽  
pp. 103-115
Author(s):  
G. Acevedo ◽  
M. A. Lugo-López ◽  
J. Ortiz-Vélez
Keyword(s):  
Size Range ◽  
Salt Content ◽  
Fine Sand ◽  
Soil Survey ◽  
Exchangeable Sodium ◽  
Sharp Reduction ◽  
Soil Extracts ◽  
Nitrogen Levels ◽  
Water Suspensions ◽  
Calcium Magnesium

The appearance of tumors or soil mounds oozing soil-water suspensions was observed during the course of a recent soil survey of Lajas Valley. The area affected lies northeast of the Guánica Lagoon and is generally covered by halophytic vegetation. Piezometer batteries installed in the area indicated a rather high upward pressure gradient throughout. This pressure is so high during rainfall, or when the sugarcane growing at the adjoining upper lands is irrigated, that water bursts through the soil, carrying along large quantities of soil particles in suspension. Studies of the mechanical composition of the soils from the tumors and from adjacent sites indicate that the majority of the moving particles are in the clay-size range, although some silt and even very fine sand are forced upward from lower depths. Most of the movement is limited, however, to the upper 48 inches. The organic-matter and nitrogen levels are higher in the soils adjacent to the tumors than in the tumors themselves, but in both there is a sharp reduction below the 24-inch depth. The cation-exchange capacities of soils from both sites are rather high, with a predominance of exchangeable sodium in the complex, and but little calcium, magnesium, and potassium. The high exchangeable-sodium percentage, together with the lower salt content of the tumors, as indicated by conductivity of soil extracts, accounts for the highly dispersed nature of the soil. The saturation percentages are extremely high, over 100 percent in most cases. They can be explained on basis of the extremely high clay percentages of the 2:1 expanding-lattice clay mineral types present.

Soil salinization at a side-hill seep and closed basin in southern Alberta

1993 ◽  
Vol 73 (2) ◽  
pp. 209-222 ◽  
Author(s):  
J. J. Miller ◽  
G. J. Beke ◽  
S. Pawluk
Keyword(s):  
Shallow Water ◽  
Water Table ◽  
Shallow Groundwater ◽  
Soil Salinization ◽  
Upward Movement ◽  
Soluble Salts ◽  
Shallow Water Table ◽  
Soil Extracts ◽  
Closed Basin ◽  
Southern Alberta

One saline soil in a side-hill seep and another in a closed basin in southern Alberta were investigated using hydrological, chemical and mineralogical techniques to compare the nature of soil salinization. The morphology of the saline Gleyed Regosolic soil in the seep indicated strong upward movement of water and soluble salts. This was evident from the presence of mottles in the soil solum, a shallow water table (≤ 2.69 m), and high EC (2.8–32.5 dS m−1) and SARt (4.8–55.5) values in the shallow groundwater and soil. High soluble Mg/Ca ratios (2.1) in the soil extract of the Ccasa3 horizon and the presence of Mg-calcites (4–5 mol %) indicated restricted leaching at this site. The morphology of the saline Orthic Dark Brown Chernozemic soil in the closed basin reflected slight upward movement of water and soluble salts. This morphology was consistent with a deeper water table (≥ 2.62 m), and lower EC (2.2–10.0 dS m−1) and SARt (2.9–11.3) values in the shallow groundwater and soil. High Mg/Ca ratios (4.8–7.0) in soil extracts of the C horizons, but no Mg-calcites, indicated greater leaching at this site. We estimated that it would take about 77 yr to salinize the soil at the seep via upward groundwater movement, and 6500 yr to salinize the soil at the closed basin. The high tritium content of the shallow groundwater at both sites suggested that downward (closed basin) and lateral (seep) movement of water to the water table was an important factor contributing to shallow water tables and soil salinization. Key words: Salinization, hydrology, chemistry, mineralogy, side-hill seep, closed basin

Changes in soils irrigated with saline groundwater containing excess bicarbonate

Soil Research ◽  
2004 ◽  
Vol 42 (7) ◽  
pp. 825 ◽  
Author(s):  
W. K. Gardner
Keyword(s):  
Soil Properties ◽  
Soil Ph ◽  
Sodium Absorption ◽  
Exchangeable Sodium ◽  
Soil Extracts ◽  
Saline Groundwater ◽  
Sodium Absorption Ratio ◽  
Carbonate Formation ◽  
Changes In Soil Properties ◽  
Gypsum Application

Changes in soil properties caused by irrigation with saline groundwater (approx. 2 dS/m) containing excess bicarbonate were measured on Vertosols and Sodosols in the West Wimmera, Victoria, Australia. Irrigation caused soil pH to increase, and where this had risen sufficiently (approx. 8.0), the sodium absorption ratio (SAR) of 1 : 5 soil extracts also increased, presumably due to precipitation of calcium and magnesium carbonates. Salt only accumulated when the SAR of 1 : 5 soil extracts was high. In contrast to previous studies, SAR of the soil extracts was not correlated with exchangeable sodium percentage (ESP) of the exchange complex, nor with soil pH. SAR values rose with irrigation once pH exceeded 8, suggesting that carbonate formation was incomplete due to insufficient bicarbonate. The results imply that gypsum application may ameliorate soil properties even if amounts applied are not sufficient to alter ESP.

scholarly journals Degree of Reclamation of a Saline-Sodic Soil in Lajas Valley, Puerto Rico

1969 ◽  
Vol 45 (3) ◽  
pp. 157-171
Author(s):  
G. Acevedo Ramos ◽  
J. A. Bonnet ◽  
J. Ortiz Vélez
Keyword(s):  
Puerto Rico ◽  
Calcium Chloride ◽  
Soil Samples ◽  
Exchangeable Sodium Percentage ◽  
Exchangeable Sodium ◽  
Soluble Salts ◽  
Sodic Soils ◽  
Soil Extracts ◽  
Sodium Percentage ◽  
Different Depths

In Lajas Valley, in southwestern Puerto Rico, there is a rather large portion of saline-sodic soils. These require reclamation if normal plant growth is to be sustained by them. A field experiment was initiated including six treatments: Two identical checks, and treatments with bagasse, bagasse-calcium chloride, sulfur, and bagasse-sulfur. The experimental plots were flooded periodically with fresh water. Soil samples were collected at different depths and analyzed to study the removal of soluble salts and exchangeable sodium. Data reported include values for electrical conductivity (EC) of soil extracts and exchangeable sodium percentage (ESP) in the soil. Results so far obtained in the reclamation experiment may be summarized as follows: 1, Application of 94 inches of water up to the maximum used to date tends to lower the soluble salts and the soil exchangeable sodium, regardless of treatment differentials. 2, The removal of the soluble salts and the reduction in exchangeable sodium were less effective in the lower layers of the soil. 3, Sulfur and calcium chloride tend to be more effective in lowering the exchangeable sodium percentage in the colloids of the surface layer of the soil. 4, There is need of a chemical amendment in addition to water and drainage if the exchangeable sodium percentage in the soil is to be lowered effectively.

scholarly journals Hydraulic conductivity in response to exchangeable sodium percentage and solution salt concentration

Revista CERES ◽  
2014 ◽  
Vol 61 (5) ◽  
pp. 715-722 ◽  
Author(s):  
Jefferson Luiz de Aguiar Paes ◽  
Hugo Alberto Ruiz ◽  
Raphael Bragança Alves Fernandes ◽  
Maria Betânia Galvão dos Santos Freire ◽  
Maria de Fatima Cavalcanti Barros ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Hydraulic Conductivity ◽  
Exchangeable Sodium Percentage ◽  
Exchangeable Sodium ◽  
Soluble Salts ◽  
Electrical Conductivities ◽  
Sodium Percentage ◽  
High Concentrations ◽  
Salt Affected Soils

Hydraulic conductivity is determined in laboratory assays to estimate the flow of water in saturated soils. However, the results of this analysis, when using distilled or deionized water, may not correspond to field conditions in soils with high concentrations of soluble salts. This study therefore set out to determine the hydraulic conductivity in laboratory conditions using solutions of different electrical conductivities in six soils representative of the State of Pernambuco, with the exchangeable sodium percentage adjusted in the range of 5-30%. The results showed an increase in hydraulic conductivity with both decreasing exchangeable sodium percentage and increasing electrical conductivity in the solution. The response to the treatments was more pronounced in soils with higher proportion of more active clays. Determination of hydraulic conductivity in laboratory is routinely performed with deionized or distilled water. However, in salt affected soils, these determinations should be carried out using solutions of electrical conductivity different from 0 dS m-1, with values close to those determined in the saturation extracts.

scholarly journals Evaluation of Salt Affected Soils for Rice (Oryza Sativa) Production in Ndungu Irrigation Scheme Same District, Tanzania

2016 ◽  
Vol 6 (1) ◽  
pp. 24 ◽  
Author(s):  
Joel L. Meliyo ◽  
Sophia Kashenge-Killenga ◽  
Kongo M. Victor ◽  
Benjamin Mfupe ◽  
Samwel Hiza ◽  
...  
Keyword(s):  
Farmyard Manure ◽  
Salt Content ◽  
Laboratory Analysis ◽  
Exchangeable Sodium Percentage ◽  
Exchangeable Sodium ◽  
Management Options ◽  
Project Area ◽  
Salt Affected Soil ◽  
Sodium Percentage ◽  
Salt Affected Soils

A study was carried out to examine distribution of salt affected soils by types and extent in the Ndungu Agricultural Development Project (NADP) area of Tanzania. The objective was to generate information to guide salt-affected soil management for sustainable rice production. Conventional methods including use of mini-pits and profile pits, coupled with farmers’ experiences were used to characterise soil. A total of seven randomly selected soil profile pits located in major soils were dug and described. Soil was sampled from natural horizons for laboratory analysis. In addition a total of 158 topsoil (0 – 20 cm depth) composites soil samples were randomly collected from 90 sites of NADP project area for laboratory analysis. Results showed that a few blocks (block is a piece of farm of 6 to 12 acres) had high exchangeable sodium percentage and high levels of bicarbonates, indicating salt-affected soils. Soil pH, exchangeable sodium percentage (ESP), and electrical conductivity of soil paste extract (ECe) values as high as 9.06, 28.7 cmol(+)Nakg-1, and 14dSm-1 were measured. Out of 90 blocks, 10 blocks (11%) showed slight to strong salt effects. Two blocks (2%) has been abandoned, and in some cultivated blocks zero yields were recorded due to salt content. The different levels of salinity development in the project area suggest site-specific remediation and appropriate management options be developed to improve crop production. These include rehabilitation of the irrigation infrastructure, use of farmyard manure as a soil amendment and growing salt-tolerant rice varieties. Furthermore, it is important to create awareness among farmers of the problem of salt-affected soil on rice productivity.

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

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