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1
Bolanle-Ojo, Tope O., Abiodun D. Joshua, Opeyemi A. Agbo-Adediran, Ademola S. Ogundana, Kayode A. Aiyeyika, Adebisi P. Ojo, and Olubunmi O. Ayodele. "Exchange Characteristics of Lead, Zinc, and Cadmium in Selected Tropical Soils." International Journal of Agronomy 2014 (2014): 1–7. http://dx.doi.org/10.1155/2014/428569.
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Conducting binary-exchange experiments is a common way to identify cationic preferences of exchangeable phases in soil. Cation exchange reactions and thermodynamic studies of Pb2+/Ca2+, Cd2+/Ca2+, and Zn2+/Ca2+were carried out on three surface (0–30 cm) soil samples from Adamawa and Niger States in Nigeria using the batch method. The physicochemical properties studies of the soils showed that the soils have neutral pH values, low organic matter contents, low exchangeable bases, and low effective cation exchange capacity (mean: 3.27 cmolc kg−1) but relatively high base saturations (≫50%) with an average of 75.9%. The amount of cations sorbed in all cases did not exceed the soils cation exchange capacity (CEC) values, except for Pb sorption in the entisol-AD2 and alfisol-AD3, where the CEC were exceeded at high Pb loading. Calculated selectivity coefficients were greater than unity across a wide range of exchanger phase composition, indicating a preference for these cations over Ca2+. TheKeqvalues obtained in this work were all positive, indicating that the exchange reactions were favoured and equally feasible. These values indicated that the Ca/soil systems were readily converted to the cation/soil system. The thermodynamic parameters calculated for the exchange of these cations were generally low, but values suggest spontaneous reactions.
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Marchuk, Alla, Pichu Rengasamy, Ann McNeill, and Anupama Kumar. "Nature of the clay - cation bond affects soil structure as verified by X-ray computed tomography." Soil Research 50, no. 8 (2012): 638. http://dx.doi.org/10.1071/sr12276.
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Non-destructive X-ray computed tomography (µCT) scanning was used to characterise changes in pore architecture as influenced by the proportion of cations (Na, K, Mg, or Ca) bonded to soil particles. These observed changes were correlated with measured saturated hydraulic conductivity, clay dispersion, and zeta potential, as well as cation ratio of structural stability (CROSS) and exchangeable cation ratio. Pore architectural parameters such as total porosity, closed porosity, and pore connectivity, as characterised from µCT scans, were influenced by the valence of the cation and the extent it dominated in the soil. Soils with a dominance of Ca or Mg exhibited a well-developed pore structure and pore interconnectedness, whereas in soil dominated by Na or K there were a large number of isolated pore clusters surrounded by solid matrix where the pores were filled with dispersed clay particles. Saturated hydraulic conductivities of cationic soils dominated by a single cation were dependent on the observed pore structural parameters, and were significantly correlated with active porosity (R2 = 0.76) and pore connectivity (R2 = 0.97). Hydraulic conductivity of cation-treated soils decreased in the order Ca > Mg > K > Na, while clay dispersion, as measured by turbidity and the negative charge of the dispersed clays from these soils, measured as zeta potential, decreased in the order Na > K > Mg > Ca. The results of the study confirm that structural changes during soil–water interaction depend on the ionicity of clay–cation bonding. All of the structural parameters studied were highly correlated with the ionicity indices of dominant cations. The degree of ionicity of an individual cation also explains the different effects caused by cations within a monovalent or divalent category. While sodium adsorption ratio as a measure of soil structural stability is only applicable to sodium-dominant soils, CROSS derived from the ionicity of clay–cation bonds is better suited to soils containing multiple cations in various proportions.
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Tucker, BM. "Active and exchangeable cations in soils." Soil Research 23, no. 2 (1985): 195. http://dx.doi.org/10.1071/sr9850195.
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The amounts of cations, Ca, Mg, K and Na, that could be extracted from soils by salt solutions varied with the cations, anions, acidity or alkalinity, and solvent of the extracting reagent. The variations were largest for soils that contained organic matter as the main source of those cations, and smallest in clay soils with little organic content. Calcium was the cation most affected and sodium the least affected. It appeared that the extractants removed all diffuse double-layer exchangeable cations, and variable portions of the other active cations including inner-sphere cations, specifically adsorbed cations, and those chelated by organic materials. A moderate, non-specific extractant containing a quaternary ammonium salt, choline chloride, is recommended for the displacement of exchangeable cations with a minimum contribution from other active cations. For an estimate of all forms of active cations, e.g. for soil nutrient assessment, a solution of ammonium sulfate is suggested.
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Wacal, Cosmas, Naoki Ogata, Daniel Basalirwa, Daisuke Sasagawa, Tsugiyuki Masunaga, Sadahiro Yamamoto, and Eiji Nishihara. "Growth and K Nutrition of Sesame (Sesamum indicum L.) Seedlings as Affected by Balancing Soil Exchangeable Cations Ca, Mg, and K of Continuously Monocropped Soil from Upland Fields Converted Paddy." Agronomy 9, no. 12 (November 29, 2019): 819. http://dx.doi.org/10.3390/agronomy9120819.
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Growth of sesame is known to be limited by poor K nutrition as a result of imbalance in soil exchangeable cations that cause a competitive ion effect in continuous monocropping from upland fields converted paddy. We hypothesized that balancing soil exchangeable cations will improve the K nutrition and growth of sesame plants. Therefore, the specific objectives of this study were to determine the effect of balancing soil exchangeable cations Ca, Mg, and K of continuously monocropped soils on the growth and cation uptake of sesame seedlings and also identify a suitable source of nutrients for improving K nutrition. A pot experiment was conducted under greenhouse condition in a 3 × 3 factorial design consisting of three levels of balancing treatments i.e. inorganic fertilizer for Ca, Mg, and K, rice husk biochar to increase K content, and the three durations of continuous monocropping soils of one year, two years, and four years from upland fields converted paddy. Balancing soil exchangeable cations was aimed at achieving optimal base saturations (CaO, 75%; MgO, 25%; and K2O, 10%). Results showed that balancing exchangeable cations did not significantly affect growth and cation uptake in the one and two-year soils but significant effect was observed in the four-year soil. Overall, plant height and dry weight increased for the balancing treatments of inorganic fertilizer K and rice husk biochar. Balancing exchangeable cations with biochar was more beneficial than with inorganic fertilizers. The four-year soil’s growth increase was attributed to an increase in K concentration and uptake due to the decrease in the soil Ca/K and Mg/K ratios to that of acceptable levels, which eliminated competitive ion effect as the soil K saturation increased above 5.0%, enhancing sesame growth. Therefore, a balanced soil exchangeable Ca, Mg, and K that eliminates a competitive ion effect will improve sesame growth and K nutrition although future research should focus on ensuring balanced cation rations under field conditions in continuous monocropping.
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Rengasamy, Pichu, and Alla Marchuk. "Cation ratio of soil structural stability (CROSS)." Soil Research 49, no. 3 (2011): 280. http://dx.doi.org/10.1071/sr10105.
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Sodium salts tend to dominate salt-affected soils and groundwater in Australia; therefore, sodium adsorption ratio (SAR) is used to parameterise soil sodicity and the effects of sodium on soil structure. However, some natural soils in Australia, and others irrigated with recycled water, have elevated concentrations of potassium and/or magnesium. Therefore, there is a need to derive and define a new ratio including these cations in place of SAR, which will indicate the dispersive effects of Na and K on clay dispersion, and Ca and Mg on flocculation. Based on the differential dispersive effects Na and K and the differential flocculation powers of Ca and Mg, we propose the concept of ‘cation ratio of soil structural stability’ (CROSS), analogous to SAR. This paper also gives the results of a preliminary experiment conducted on three soils varying in soil texture on hydraulic conductivity using percolating waters containing different proportions of the cations Ca, Mg, K, and Na. The relative changes in hydraulic conductivity of these soils, compared with the control treatment using CaCl2 solution, was highly correlated with CROSS. Clay dispersion in 29 soils treated with irrigation waters of varying cationic composition was highly correlated with CROSS rather than SAR. It was also found that CROSS measured in 1 : 5 soil/water extracts was strongly related to the ratio of exchangeable cations. These results encourage further study to investigate the use of CROSS as an index of soil structural stability in soils with different electrolytes, organic matter, mineralogy, and pH.
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Wang, Ruzhen, Xue Wang, Yong Jiang, Artemi Cerdà, Jinfei Yin, Heyong Liu, Xue Feng, Zhan Shi, Feike A. Dijkstra, and Mai-He Li. "Soil properties determine the elevational patterns of base cations and micronutrients in the plant–soil system up to the upper limits of trees and shrubs." Biogeosciences 15, no. 6 (March 26, 2018): 1763–74. http://dx.doi.org/10.5194/bg-15-1763-2018.
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Abstract. To understand whether base cations and micronutrients in the plant–soil system change with elevation, we investigated the patterns of base cations and micronutrients in both soils and plant tissues along three elevational gradients in three climate zones in China. Base cations (Ca, Mg, and K) and micronutrients (Fe, Mn, and Zn) were determined in soils, trees, and shrubs growing at lower and middle elevations as well as at their upper limits on Balang (subtropical, SW China), Qilian (dry temperate, NW China), and Changbai (wet temperate, NE China) mountains. No consistent elevational patterns were found for base cation and micronutrient concentrations in both soils and plant tissues (leaves, roots, shoots, and stem sapwood). Soil pH, soil organic carbon (SOC), total soil nitrogen (TN), the SOC to TN ratio (C : N), and soil extractable nitrogen (NO3− and NH4+) determined the elevational patterns of soil exchangeable Ca and Mg and available Fe, Mn, and Zn. However, the controlling role of soil pH and SOC was not universal as revealed by their weak correlations with soil base cations under tree canopies at the wet temperate mountain and with micronutrients under both tree and shrub canopies at the dry temperate mountain. In most cases, soil base cation and micronutrient availabilities played fundamental roles in determining the base cation and micronutrient concentrations in plant tissues. An exception existed for the decoupling of leaf K and Fe with their availabilities in the soil. Our results highlight the importance of soil physicochemical properties (mainly SOC, C : N, and pH) rather than elevation (i.e., canopy cover and environmental factors, especially temperature), in determining base cation and micronutrient availabilities in soils and subsequently their concentrations in plant tissues.
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Echeverría, Jesús, Teresa Morera, and Julián Garrido. "Metal-induced chromium(VI) sorption by two calcareous soils." Soil Research 37, no. 3 (1999): 431. http://dx.doi.org/10.1071/s98079.
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Competing anions, notably SO 2- 4 and H2PO- 4 , reduce Cr(VI) sorption; however, the role of cooperative cations in Cr(VI) retention has merited less attention. This research studied the effect of Cd, Cu, Ni, and Zn on sorption of Cr(VI) in 2 calcareous soils: Calcixerollic Xerochrept (CX) and Paralithic Xerorthent (PX). Sorption kinetics and isotherms were combined with sequential extractions and fractional factorial designs. Most cation sorption took place during the first hour, whereas sorption of Cr(VI) was slower. Without the cooperative presence of these cations, no sorption of Cr(VI) was detected in the range 0–0·35 mM. Cd, Cu, Ni, and Zn augmented the sorption of Cr(VI) by the calcareous soils; however, in both soils the amount of Cr(VI) retained was much lower than cation sorption. In the presence of cation, sorption of Cr(VI) was first observed at an equilibrium concentration of 0·07 mM for the CX soil and 0·17 mM for the PX soil. For higher concentrations, sorption of Cr(VI) by both soils was described by a constant distribution isotherm. More than 80% of Cr(VI) sorbed by soils was extracted as a non-exchangeable fraction using the Tessier et al . sequential procedure. Fractional factorial designs indicated that although the 4 cations favoured sorption of Cr(VI), Cu had the greatest positive influence.
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Gillman, G. P., D. C. Burkett, and R. J. Coventry. "A laboratory study of application of basalt dust to highly weathered soils: effect on soil cation chemistry." Soil Research 39, no. 4 (2001): 799. http://dx.doi.org/10.1071/sr00073.
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Surface (0–10 cm) samples from 7 highly weathered soils in tropical coastal Queensland were incubated for 3 months at room temperature and at field moisture capacity with basalt dust applied in 2 size fractions: <150 µm and 40 µm. The basalt application was mixed at 0, 1, 5, 25, and 50 t/ha to cover situations of moderate applications as well as where the amendment might be banded to achieve high local concentrations. Basalt dust application caused desirable increases in soil pH, reduced the content of exchangeable acidic cations, increased soil cation exchange capacity, and increased the content of base cations in all soils. By determining fundamental surface charge characteristics of these variable charge soils, it was possible to show that the additional base cations released from the basalt dust were present as exchangeable cations, and that the amounts released were controlled by the number of negatively charged sites available, i.e. soil cation exchange capacity. Selected treatments were then subjected to a strong leaching environment to assess the longevity of the effects obtained. Soil properties remained virtually unchanged by the leaching treatment, except that significant amounts of monovalent K and Na were removed. At the higher rates of application, the amounts of base cations released from the basalt were small in comparison with the actual amounts applied, indicating that the amendment could be effective over a considerable period of time.
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Yuan, Jin-Hua, and Ren-Kou Xu. "Effects of biochars generated from crop residues on chemical properties of acid soils from tropical and subtropical China." Soil Research 50, no. 7 (2012): 570. http://dx.doi.org/10.1071/sr12118.
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The chemical compositions of biochars from ten crop residues generated at 350°C and their effects on chemical properties of acid soils from tropical and subtropical China were investigated. There was greater alkalinity and contents of base cations in the biochars from legume residues than from non-legume residues. Carbonates and organic anions of carboxyl and phenolic groups were the main forms of alkalis in the biochars, and their relative contributions to biochar alkalinity varied with crop residues. Incubation experiments indicated that biochar incorporation increased soil pH and soil exchangeable base cations and decreased soil exchangeable acidity. There were greater increases in soil pH and soil exchangeable base cations, and a greater decrease in soil exchangeable acidity, for biochars from legume than from non-legume residues. The biochars did not increase the cation exchange capacity (CEC) of soils with relatively high initial CEC but did increase the CEC of soils with relatively low initial CEC at an addition level of 1%. The incorporation of biochars from crop residues not only corrected soil acidity but also increased contents of potassium, magnesium, and calcium in these acid soils from tropical and subtropical regions and thus improved soil fertility.
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Marchuk, Alla, and Pichu Rengasamy. "Threshold electrolyte concentration and dispersive potential in relation to CROSS in dispersive soils." Soil Research 50, no. 6 (2012): 473. http://dx.doi.org/10.1071/sr12135.
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We have used the newly developed concept of CROSS (cation ratio of soil structural stability) instead of SAR (sodium adsorption ratio) in our study on dispersive soils. CROSS incorporates the differential dispersive powers of Na and K and the differences in the flocculating effects of Ca and Mg. The CROSS of the dispersed soil solutions, from the differently treated soils of three soil types varying in clay content, mineralogy, and organic matter, was highly correlated with the amount of clay dispersed. The relation between CROSS and exchangeable cation ratio depended on soil type, and particularly organic matter and the content and mineralogy of clay. Threshold electrolyte concentration of the flocculated suspensions was significantly correlated with CROSS of the dispersed suspensions. The cationic flocculating charge of the flocculated suspensions, which incorporates the individual flocculating powers of the cations, was significantly correlated with CROSS. However, these types of relations will depend on several soil factors even within a given soil class. Therefore, we have derived the dispersive potential of an individual soil from which we calculated the required cationic amendments to maintain flocculated soils and their structural integrity.
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Marchuk, Alla, Pichu Rengasamy, and Ann McNeill. "Influence of organic matter, clay mineralogy, and pH on the effects of CROSS on soil structure is related to the zeta potential of the dispersed clay." Soil Research 51, no. 1 (2013): 34. http://dx.doi.org/10.1071/sr13012.
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The high proportion of adsorbed monovalent cations in soils in relation to divalent cations affects soil structural stability in salt-affected soils. Cationic effects on soil structure depend on the ionic strength of the soil solution. The relationships between CROSS (cation ratio of soil structural stability) and the threshold electrolyte concentration (TEC) required for the prevention of soil structural problems vary widely for individual soils even within a soil class, usually attributed to variations in clay mineralogy, organic matter, and pH. The objective of the present study was to test the hypothesis that clay dispersion influenced by CROSS values depends on the unique association of soil components, including clay and organic matter, in each soil affecting the net charge available for clay–water interactions. Experiments using four soils differing in clay mineralogy and organic carbon showed that clay dispersion at comparable CROSS values depended on the net charge (measured as negative zeta potential) of dispersed clays rather than the charge attributed to the clay mineralogy and/or organic matter. The effect of pH on clay dispersion was also dependent on its influence on the net charge. Treating the soils with NaOH dissolved the organic carbon and increased the pH, thereby increasing the negative zeta potential and, hence, clay dispersion. Treatment with calgon (sodium hexametaphosphate) did not dissolve organic carbon significantly or increase the pH. However, the attachment of hexametaphosphate with six charges on each molecule greatly increased the negative zeta potential and clay dispersion. A high correlation (R2 = 0.72) was obtained between the relative clay content and relative zeta potential of all soils with different treatments, confirming the hypothesis that clay dispersion due to adsorbed cations depends on the net charge available for clay–water interactions. The distinctive way in which clay minerals and organic matter are associated and the changes in soil chemistry affecting the net charge cause the CROSS–TEC relationship to be unique for each soil.
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Khanna, PK, B. Ludwig, and RJ Raison. "Comparing modelled and observed effects of ash additions on chemistry of a highly acid soil." Soil Research 34, no. 6 (1996): 999. http://dx.doi.org/10.1071/sr9960999.
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The chemical composition of soil solutions (field percolates collected in situ and laboratory saturation extracts) and the amount of salt-extractable cations were measured at several microsites (unburnt, moderately burnt, and intensely burnt ashbeds) after a fuel reduction burning in a subalpine Eucalyptus pauciflora forest. Soil samples were collected 1, 58, 375, 745, and 1095 days after the fire, and soil percolates were obtained on 17 occasions during the initial year. A model of coupled equilibria, which includes insoluble salts, multiple cation exchange, and inorganic complexation, was used to describe soil chemical changes after fire and ash addition. The model was able to describe temporal changes in cation concentrations of held percolates and soil exchangeable cations. Measurements of extractable cations using unbuffered salt solution on samples taken immediately after fire suggest immediate changes in exchangeable cations which were related to solubilisation of cations from ash, and not to changes in exchangeable cations in soils. Modelling suggests that under natural conditions the differences in solubility of cations in ash result in slow changes in exchangeable cations extending over a period of 6 years or more. The time required to reacidify the surface layer of ashbed soil was estimated to be 45 years when annual acid input was 0.5 kmol H+/ha.
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Heng, L. K., R. W. Tillman, and R. E. White. "Anion and cation leaching through large undisturbed soil cores under different flow regimes. 1. Experimental results." Soil Research 37, no. 4 (1999): 711. http://dx.doi.org/10.1071/sr98002.
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The movement of anions and cations under different unsaturated flow regimes was studied in 2 large undisturbed cores from a soil under pasture. Sequential leaching of calcium sulfate (CaSO4) and potassium bromide (KBr) solutions was carried out at water fluxes which ranged from a normal 5–20 mm/h rate in one core (the slow flow core), to unusually high values up to 350 mm/h in the other (the fast flow core). The objective was to examine the leaching behaviour of the applied cations and anions under these contrasting flow conditions, and determine the relative influence of soil physical and chemical processes in governing ion movement. A better understanding of this behaviour should help in the development of improved practices to reclaim saline soils, ameliorate sodic soils, and minimise unwanted leaching of nutrients. In the slow flow core, miscible displacement breakthrough curves (BTCs) were observed for bromide, with sulfate movement retarded relative to the bromide. Cation exchange reactions occurred in the slow flow core, with calcium generally the dominant cation balancing anions during their movement through the soil. When KBr solution was substituted for CaSO4, potassium ions replaced calcium ions on the exchange sites, resulting in an increase in the calcium concentration in the effluent. In the fast flow core, however, flow was highly preferential and the water flux very variable. The surface-applied solutes appeared very rapidly in the effluent, irrespective of whether they were cations or anions. Under these conditions, solution cation/anion interactions with the soil surfaces did not appear to approach equilibrium, so that the leaching process was dominated by the soil’s water flow characteristics and showed little influence of surface chemical reactions.
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Wang, Shiyu, Junnan Zhang, Fada Zhou, Cunzhen Liang, Liao He, Wentao Jiao, and Wenyong Wu. "Adsorption of EDCs on Reclaimed Water-Irrigated Soils: A Comparative Analysis of a Branched Nonylphenol, Nonylphenol and Bisphenol A." Water 13, no. 18 (September 15, 2021): 2532. http://dx.doi.org/10.3390/w13182532.
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Nonylphenol (NP) and bisphenol A (BPA) are two typical endocrine disrupter chemicals (EDCs) in reclaimed water. In this study, the adsorptions of NP, a branched NP (NP7) and BPA on reclaimed water-irrigated soils were studied by isothermal experiments, and the different environmental factors on their adsorptions were investigated. The results showed that the adsorptions of NP and NP7 on soils conformed to the Linear model, and the adsorption of BPA conformed to the Freundlich model. The adsorptions of NP, NP7 and BPA on soils decreased with increasing temperatures and pHs. Adsorption equilibrium constant (Kd or Kf) were maximum at pH = 3, temperature 25 °C and As(III)-soil, respectively. The adsorption capacity of NP, NP7 and BPA to soils under different cation valence were as follows: neutrally > divalent cations > mono-cations. Kd of NP7 on soil was less than that of NP under different pH and temperatures, while under different cation concentrations it was the inverse. Fourier Transform Infrared Spectrometer (FTIR) analysis showed alkyl chains of NP and BPA seemed to form van der Waals interactions with the cavity of soil. Results of this study will provide further comprehensive fundamental data for human health risk assessment of NP and BPA in soil.
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Fenn, M. E., T. G. Huntington, S. B. McLaughlin, C. Eagar, A. Gomez, and R. B. Cook. "Status of soil acidification in North America." Journal of Forest Science 52, Special Issue (January 1, 2006): S3—S13. http://dx.doi.org/10.17221/10152-jfs.
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Forest soil acidification and depletion of nutrient cations have been reported for several forested regions in North America, predominantly in the eastern United States, including the northeast and in the central Appalachians, but also in parts of southeastern Canada and the southern U.S. Continuing regional inputs of nitrogen and sulfur are of concern because of leaching of base cations, increased availability of soil Al, and the accumulation and ultimate transmission of acidity from forest soils to streams. Losses of calcium from forest soils and forested watersheds have now been documented as a sensitive early indicator and a functionally significant response to acid deposition for a wide range of forest soils in North America. For red spruce, a clear link has been established between acidic deposition, alterations in calcium and aluminum supplies and increased sensitivity to winter injury. Cation depletion appears to contribute to sugar maple decline on some soils, specifically the high mortality rates observed in northern Pennsylvania over the last decade. While responses to liming have not been systematically examined in North America, in a study in Pennsylvania, restoring basic cations through liming increased basal area growth of sugar maple and levels of calcium and magnesium in soil and foliage. In the San Bernardino Mountains in southern California near the west coast, the pH of the A horizon has declined by at least 2 pH units (to pH 4.0–4.3) over the past 30 years, with no detrimental effects on bole growth; presumably, because of the Mediterranean climate, base cation pools are still high and not limiting for plant growth.
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Olchawa, Andrzej, and Aleksandra Gorączko. "The relationship between the liquid limit of clayey soils, external specific surface area and the composition of exchangeable cations / Zależność granicy płynności od zewnętrznej powierzchni właściwej i składu kationów w naturalnym kompleksie wymiennym." Journal of Water and Land Development 17, no. 1 (December 1, 2012): 83–88. http://dx.doi.org/10.2478/v10025-012-0037-5.
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Abstract The liquid limit - wL, the external surface area - Se, the concentration of exchangeable cations - Zi and the cation exchange capacity - CEC of seventeen clayey soils were determined. Finding the correlation between the liquid limit, external specific surface area and exchangeable cation concentration was the aim of this study. Experimental study performed using soils of the external surface area within the range of 4.1 to 118.5 m2·g-1. The relative content of sodium cation (i.e. Na+/CEC) varying between 0.03 and 1.0. Obtained results point to statistically significant relationship between these three properties. The greatest predictive power of linear regression was found for soils of external specific surface area larger than 60 m2·g-1. For the soils of comparable external surface area, the liquid limit increase with increasing the ratio of the content of sodium cation to the cation exchange capacity - Na+/CEC. For the soils of comparable composition of exchangeable cations the liquid limit increase with increasing the external surface area. These relationships indicates that interparticle forces have a prominent role in determining liquid limit of clayey soils.
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Menzies, NW, LC Bell, and DG Edwards. "Exchange and solution phase chemistry of acid, highly weathered soils .I. Characteristics of soils and the effects of lime and gypsum amendments." Soil Research 32, no. 2 (1994): 251. http://dx.doi.org/10.1071/sr9940251.
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Exchange and solution phase characteristics were evaluated on surface and subsoil horizons of 60 acid, highly weathered soils in the unamended state, and on 39 of the surface horizons following addition of CaCO3 or CaSO4.2H2O. Soil solutions from unamended surface samples were dominated by Na (median concentration 0.65 mM), while the other major cations were present at lower levels (median concentrations: Ca, 0.09; Mg, 0.14; K, 0.28 mM). This pattern was more pronounced in the subsoil samples where the median concentrations of the nutrient cations were < 0.05 mM, whereas the median concentration of Na was 0.28 mM. The cation exchange capacity of surface samples was dominated by Ca, Mg and Al, while Al was the major exchangeable cation in the subsoil. Addition Of CaSO4.2H2O decreased soil solution pH and increased electrical conductivity and the concentration of Ca, Mg, Na, K and Al in the soil solution. The soil solution pH change resulting from CaSO4.2H2O addition could not be predicted on the basis of the characteristics of the soil in the unamended state.
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Heck, R. J., and A. R. Mermut. "The chemistry of saturation extracts of Solonetzic and associated soils." Canadian Journal of Soil Science 72, no. 1 (February 1, 1992): 43–56. http://dx.doi.org/10.4141/cjss92-005.
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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
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Mokwenye, Ifesinachi I., Paul N. Diagboya, Bamidele I. Oluowolabi, Ikenna O. Anigbogu, and Hilary I. Owamah. "Immobilization of toxic metal cations on goethite-amended soils: a remediation strategy." Journal of Applied Sciences and Environmental Management 20, no. 2 (July 25, 2016): 436–43. http://dx.doi.org/10.4314/jasem.v20i2.26.
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The study investigates a simple and viable option to reduce toxic metals mobility and availability in four surface (0–30cm) soils with varying physicochemical properties amended by different percentages of goethite. Batch sorption experiments carried out to study the effectiveness of immobilizing Pb2+, Cu2+, Zn2+ and Cd2+ ions on these soils showed that goethite played vital role in the metals adsorption (≥10% increase in adsorption). Removal of soil iron oxides caused reduced Pb2+ adsorption on soils with high organic matter (≤ 10% decrease in adsorption) with no significant increase in adsorption upon amendment, while soils having low organic matter had enhanced adsorption with amendment. Cu2+ and Cd2+ adsorptions were not enhanced even at 10% goethite amendment. However, Zn2+ adsorption was interestingly different: the soils showed ≥55 % increases upon removal of inherent soil iron oxides without goethite amendment. Goethite amendments further enhanced Zn2+ adsorption on these soils. Generally, both whole and amended soils showed higher preference for Pb2+; the sorption trend is – Pb2+ >Cu2+ >Zn2+ >Cd2+. Goethite amendment of these soils improved Pb2+ and Zn2+ adsorption. Hence, goethite amendment may be an effective method for immobilizing Pb2+ and Zn2+ on these soils and thus reducing their availability to biota. The quantity of goethite required by a soil to attain maximum immobilization varies depending on the metal and the soil’s physicochemical properties; however, Cu2+ and Cd2+ may not be effectively immobilized using goethite amendment.Keywords: Soil; Goethite; Toxic metals; Adsorption, Remediation
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Sufardi, Sufardi, Teti Arabia, Khairullah Khairullah, Karnilawati Karnilawati, Sahbudin Sahbudin, and Zainabun Zainabun. "Charge Characteristics and Cation Exchanges Properties of Hilly Dryland Soils Aceh Besar, Indonesia." Aceh International Journal of Science and Technology 9, no. 2 (September 7, 2020): 90–101. http://dx.doi.org/10.13170/aijst.9.2.17565.
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Soil surface charge and cation exchange are important parameters of soil fertility in tropical soils. This study was conducted to investigate characteristics of surface charges and cation exchanges on four soil orders of the dryland in Aceh Besar district. The soil order includes Entisols Jantho (05o16’58.41” N; 95o37’51.82” E), Andisols Saree (05o27'15.6" N; 95o44'09,1" E), Inceptisols Cucum (05º18’18,37” N; 95º32’48,04” E), dan Oxisols Lembah Seulawah (05o27’19,4” N; 95o46’19,2” E). The charge characteristics of surface charge are evaluated from the parameter of DpH (pHH2O-pHKCl), variable charge (Vc), permanent charge (Pc), and point of zero charges (PZC). In contrast, cation exchange properties are evaluated from several soil chemical properties, such as soil organic matter (SOM), base saturation (BS), cation exchange capacity (CEC), and effective CEC (ECEC). The results show that the four pedons of soil in the hilly dryland of Aceh Besar include a variable charge because it has a PZC, which is characterized by a negative surface charge with a PZC of pHH2O and has CEC dependent soil pH. PZC value varies from 3.21 – 5.26 and sequentially PZC Andisols Oxisols Entisols Inceptisols. The total CEC value differs considerably from ECEC and the sum of cations. CEC total of the soils varies from 12.8 – 34.4 cmol kg-1, whereas the ECEC values vary from 2.72 – 8.66 cmol kg-1. The highest variable charge percentage is found in Andisols Saree. In contrast, the highest permanent charge is found in Inceptisols Cucum and is positively correlated with pHH20, PZC, CEC, and sums of cations or ECEC. Improving soil quality in hilly dryland soils in Aceh Besar District can be done by decreasing the PZC status of soils with organic amendments and fertilizers or increasing the pH by using liming.
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Maslennikov, B. I., Yu N. Matveev, V. N. Bogatikov, and N. A. Stukalova. "Features of the Sorption Process of Polyvalent Metal Cations in Soils." Ecology and Industry of Russia 23, no. 3 (March 12, 2019): 14–19. http://dx.doi.org/10.18412/1816-0395-2019-3-14-19.
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The issue of migration and accumulation of harmful and toxic compounds in soils is considered. Particular attention is paid to the study of the rate of ion-exchange process of cations of copper, iron, zinc, aluminum on humic acids, since these elements constitute a significant mass of harmful emissions from industrial enterprises in the form of drainage effluents to be cleaned. The results of studies of mass transfer processes in soils for various compounds are presented. An approach is proposed based on the calculation of the average dynamic value of the charge of a polyvalent metal cation extinguished when interacting with a specific sorbent, which allows a predictive estimate of the migration and accumulation of this cation within the spill of its salt solution on the soil.
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Hou, Enqing, Dazhi Wen, Jianli Li, Weidong Zuo, Lingling Zhang, Yuanwen Kuang, and Jiong Li. "Soil acidity and exchangeable cations in remnant natural and plantation forests in the urbanised Pearl River Delta, China." Soil Research 50, no. 3 (2012): 207. http://dx.doi.org/10.1071/sr11344.
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Increasing urbanisation and industrialisation have led to a dramatic reduction in forest area, and now only culturally protected remnants of natural forests and some new plantations remain in most areas of the Pearl River Delta (PRD), China. To investigate the status of soil acidity and exchangeable cations under these remnant forests and assess the possible impacts of reforestation on soil nutrients in the plantation forests, soils at 0–0.03, 0.03–0.13, and 0.13–0.23 m depths were sampled from 16 forest patches (eight natural and eight plantations), and soil pH in water, organic matter content, and exchangeable cation (H, Al, Ca, Mg, K, and Na) contents were determined. Results showed that 90% of the soils were strongly acid (pH <4.5) and 70% of the soils had a base saturation <15%. About 50% of the soils had <0.5 mmol(+)/kg of exchangeable Mg. Soil exchangeable K and Mg contents were significantly lower under plantation forests than under native forests in all layers, whereas exchangeable Ca and Na contents showed little difference between two types of forests. Moreover, contents of all exchangeable cations except Al showed a significant decrease with depth. These results suggest that remnant forests in the PRD generally experience a high risk of Al and acidity stresses and non-acidic cation deficiencies for plant growth. Reforestation may cause further decline in soil exchangeable K and Mg contents, but is unlikely to affect soil exchangeable Ca and Na contents.
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Jaremko, Dawid, and Dorota Kalembasa. "A Comparison of Methods for the Determination of Cation Exchange Capacity of Soils/Porównanie Metod Oznaczania Pojemności Wymiany Kationów I Sumy Kationów Wymiennych W Glebach." Ecological Chemistry and Engineering S 21, no. 3 (October 1, 2014): 487–98. http://dx.doi.org/10.2478/eces-2014-0036.
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Abstract The object of this study was to compare the results obtained with four methods of determination of cation exchange capacity (CEC) and sum of exchangeable cations (Ca, Mg, K) in soils. One of these methods is Kappen’s method and the others methods are based on different extracting reagents: sodium acetate (pH = 8.2), barium chloride and hexaamminecobalt(III) chloride. Values measured with barium ions and hexaamminecobalt(III) ions as index cations are very comparable and these two methods can be considered as equivalent. Kappen’s method gives overestimated results, especially for acid soils reach in organic matter and very calcareous soils. Sodium acetate, buffering the pH of the extracting solution, causes increase of numbers of negatively charged sites and particularly those bonded to organic matter and for this reason values obtained with this method are overestimated. Nevertheless, it is possible to correct this error for a given soil sample by regression equation considering pH of soil, clay and organic carbon content.
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Tolimir, Miodrag, Branka Kresović, Borivoj Pejić, Katarina Gajić, Angelina Tapanarova, Zorica Sredojević, and Boško Gajić. "Chemical properties of long-term irrigated Fluvisols of the Beli Drim river valley in the Klina region (Serbia)." Zemljiste i biljka 70, no. 1 (2021): 13–26. http://dx.doi.org/10.5937/zembilj2101013t.
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The impact of long-term (> 100 yr) irrigation on soil chemical properties was studied on eight plots in the Beli Drim river valley in Kosovo and Metohija near Klina, Serbia. For these studies, soil samples from shallow profiles were collected from only one or two depth zones of the Ah horizon; and from moderately deep and deep profiles, from two to three depth zones for the purpose of comparing irrigated field and non-irrigated meadow lands. Water from the Beli Drim River and surface gravity systems (irrigation furrows or border strip irrigation) were used for irrigation. Chemical variables included determination of pH-H2O, content of CaCO3, content of humus, hydrolytic acidity, sum of basic cations, cation exchange capacity, and base saturation. On irrigated soils, the results of chemical analysis showed on average a small increase in pH-H2O (0.07 pH units), as well as a significant decrease in humus content (2.00-4.75%), sum of basic cations (4.98-12.98%) and cation exchange capacity (12.8%) compared to the non-irrigated land of the study area. Long-term irrigation had no effect on hydrolytic acidity and base saturation in the Ah horizon of the investigated lands. Namely, the mentioned variations in the chemical properties of the investigated soils show that slight processes of reduction in the humus content and reduction of the content of base cations occured. Data on the chemical properties of the investigated soils indicate that the destructive processes of reduction in the humus content and leaching of base cations must be controlled in order to achieve a stable sustainable system of high productivity and prevent their further deterioration.
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Teutscherova, Nikola, Bohdan Lojka, Marta Benito, Alberto Masaguer, and Eduardo Vázquez. "Biochar Reduces the Stability of Soil Aggregates during Intensive Leaching Experiment." Agronomy 10, no. 12 (December 3, 2020): 1910. http://dx.doi.org/10.3390/agronomy10121910.
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The interplay of different mechanisms shaping the biochar impact on soil structure remains relatively unexplored. We investigated the impact of biochar application to two contrasting soils on the stability of soil aggregates under an intensive intermittent leaching regime. A greenhouse experiment was established using PVC columns filled with 500 g soil from an Acrisol or Calcisol amended with three biochar applications (0, 1 and 2% w/w). The columns were watered weekly (100 mL) during two leaching cycles (each lasting 10 weeks). The amount of leached base cations, the stability of 1–2 mm aggregates fraction and soil chemical properties were determined. Biochar enhanced the leaching of the studied cations, but the content of base cations and effective cation exchange capacity remained higher in the biochar-amended Acrisol when compared to control soil. In both soils, biochar reduced the amount of water-stable aggregates, which seemed to be attributed to the increase of K in the exchange complex in the Acrisol while no significant correlation was detected between aggregation in Calcisol and other variables. The negative impact of biochar on soil aggregation is likely linked to higher sensitivity of biochar-amended soils to aggregate disruption under changing moisture conditions caused by frequent and intensive leaching events. These results highlight the gaps in our understanding of biochar impact on soil aggregation, which have implications for soil erodibility or restoration of degraded lands under changing climate.
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Lavkulich, L. M., and J. M. Arocena. "Luvisolic soils of Canada: Genesis, distribution, and classification." Canadian Journal of Soil Science 91, no. 5 (October 2011): 781–806. http://dx.doi.org/10.4141/cjss2011-014.
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Lavkulich, L. M. and Arocena, J. M. 2011. Luvisols of Canada: Genesis, distribution, and classification. Can. J. Soil Sci. 91: 781–806. Luvisols link the soil continuum on the Quaternary landscapes. These soils are developed from parent materials rich in Ca and Mg in a relatively humid climate. An acidic eluvial horizon overlying a phyllosilicate-enriched illuvial Bt horizon is the common horizon sequence in Luvisolic soils. Lessivage or the translocation of clays with minimal chemical alteration is the characteristic soil-forming process and results to the diagnostic Bt horizon with well-developed, oriented clay skins or cutans. These soils commonly form intergrades with Chernozems, Podzols and Vertisols. With time, the eluvial horizons experience increased chemical weathering and further release of sequioxides to form Brunisolic and Podzolic sequences within the eluvial Ae in biseqeual soils. Lessivage significantly influences several ecosystem functions of soils. The high amounts of phyllosilicates in the Bt horizon serve as one of the most active sorption sites in soils for metals and organic materials including soil carbon. Sorption of cations takes place through cation exchange reactions and determines the availability of cations to plant roots as well as in the “colloid facilitated transport” of strongly sorbing metals and organic pollutants. Clays in Bt can be restrictive to water and air movement as well as to root growth and distribution. Agricultural and forestry practices such as tillage can compact the structure of Luvisols and may decrease soil productivity.
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Houle, Daniel, Rock Ouimet, Suzanne Couture, and Christian Gagnon. "Base cation reservoirs in soil control the buffering capacity of lakes in forested catchments." Canadian Journal of Fisheries and Aquatic Sciences 63, no. 3 (March 1, 2006): 471–74. http://dx.doi.org/10.1139/f06-007.
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The acidification of forest soils and surface waters and their relatively poor recovery record following reductions in atmospheric sulphur emissions is a major ongoing environmental problem, particularly in northeastern North America. The slow recovery of surface water is widely hypothesized to result from depletion of reservoirs of base cations in soil. This is concordant with the theory that the acid-neutralizing capacity (ANC) of lakes is likely proportional to the size of the exchangeable base cation reservoirs present in surrounding watershed soils. However, data describing these linkages are still nonexistent in the literature. Here we show that lake ANC is highly predictable (r2 = 0.75) based on the size of the exchangeable Ca2+ reservoir in soil in 21 catchments representative of soil and lake conditions encountered in northeastern North America. This finding indirectly supports the hypothesis that the poor recovery of surface water from acidification is governed by the size of base cation reservoirs present in catchment soils. The size of the base cation reservoir in soil is thus a strong indicator of the acidbase status of both soils and surface waters.
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Stutter, M. I., M. S. Alam, S. J. Langan, S. J. Woodin, R. P. Smart, and M. S. Cresser. "The effects of H2SO4 and (NH4)2SO4 treatments on the chemistry of soil drainage water and pine seedlings in forest soil microcosms." Hydrology and Earth System Sciences 8, no. 3 (June 30, 2004): 392–408. http://dx.doi.org/10.5194/hess-8-392-2004.
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Abstract. An experiment comparing effects of sulphuric acid and reduced N deposition on soil water quality and on chemical and physical growth indicators for forest ecosystems is described. Six H2SO4 and (NH4)2SO4 treatment loads, from 0 – 44 and 0 – 25 kmolc ha-1 yr-1, respectively, were applied to outdoor microcosms of Pinus sylvestris seedlings in 3 acid to intermediate upland soils (calc-silicate, quartzite and granite) for 2 years. Different soil types responded similarly to H2SO4 loads, resulting in decreased leachate pH, but differently to reduced N inputs. In microcosms of calc-silicate soil, nitrification of NH4 resulted in lower pH and higher cation leaching than in acid treatments. By contrast, in quartzite and granite soils, (NH4)2SO4 promoted direct cation leaching, although leachate pH increased. The results highlighted the importance of soil composition on the nature of the cations leached, the SO4 adsorption capacities and microbial N transformations. Greater seedling growth on calc-silicate soils under both treatment types was related to sustained nutrient availability. Reductions in foliar P and Mg with higher N treatments were observed for seedlings in the calc-silicate soil. There were few treatment effects on quartzite and granite microcosm tree seedlings since P limitation precluded seedling growth responses to treatments. Hence, any benefits of N deposition to seedlings on quartzite and granite soils appeared limited by availability of co-nutrients, exacerbated by rapid depletion of soil exchangeable base cations. Keywords: acidification, manipulation, nitrogen, ammonium, deposition, soil, drainage, pine, microcosms, forest
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Porębska, Grażyna, and Apolonia Ostrowska. "Relationships between exchangeable and water-soluble cations in the forest soil." Ochrona Srodowiska i Zasobów Naturalnych 27, no. 3 (September 1, 2016): 1–7. http://dx.doi.org/10.1515/oszn-2016-0017.
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AbstractThe aim of this research was to assess the relationships between exchangeable and water-soluble cations in forest soil types. Three dominant soil types were distinguished on studied plots: Haplic Podzol, Dystric Arenosol and Dystric Cambisol. Ca, Mg, K, Na and Al in soil sorption complex and soil water extracts were determined. The differentiation of the ionic composition of soil sorption complex and soil water extracts within a soil type and amongst soil types was presented. The sum of cations in the soil and water extracts was the highest in Dystric Cambisol and the lowest in Haplic Podzol. Ca is a dominant cation in soil and soil water extracts in organic horizon, whilst Al is dominant in mineral soil horizons. The Ca/Al and the base cations to Al (BC/Al) molar ratios increased in the sequence of soils: Haplic Podzol < Dystric Arenosol < Dystric Cambisol. The parent material, soil-forming processes and vegetation cover affected the Ca/Al and BC/Al ratios.
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Smiles, D. E., and C. J. Smith. "A survey of the cation content of piggery effluents and some consequences of their use to irrigate soils." Soil Research 42, no. 2 (2004): 231. http://dx.doi.org/10.1071/sr03059.
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Piggery effluent contains high concentrations of potassium, and its repeated irrigation raises soil exchangeable potassium to levels, relative to divalent cations, that may degrade soil structure. We surveyed 6 big piggeries extending from south-eastern Queensland on a self-mulching Vertosol, to an Arenic Rudosol in south-eastern South Australia. We sampled effluent used for irrigation and also soil profiles to permit 'fenceline' comparisons between soils that had and had not been irrigated. The major water-soluble cations sodium (Na+), potassium (K+), calcium (Ca2+), and magnesium (Mg2+) were measured in the effluent and the soil saturation extracts, and also their exchangeable forms on air-dried soil samples. Ammonium-nitrogen (NH4+-N) was also assayed. The effluents were similar, with pH values between 7.5 and 8 together with very high water-soluble NH4-N, lower values for K+ and Na+, and quite low concentrations of Ca2+ and Mg2+. Cation concentrations varied across effluents; sodium and potassium adsorption ratios (SAR and KAR) were relatively constant but smaller than an ammonium adsorption ratio (Am-AR), which we conceive to estimate the influence of NH4+-N relative to the divalent cations in the effluent. Exchangeable K+ ratios in all profiles that had been irrigated were greater than their non-irrigated partners, as were the KAR values in their saturation extracts. Despite high concentrations of NH4+-N and high values of Am-AR in the effluents, there was no evidence of exchangeable NH4+ in the soils when sampled, which, we presume, is rapidly taken up by plants or oxidised. We present data that support a useful relationship between total cation content and effluent and the soil saturation extract electrical conductivity (EC), We also observed a modest increase in the EC of the saturation extract of irrigated soils. Farm records were insufficient to permit material balance calculations.
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Bestland, Erick A., and Matthew S. Forbes. "Evidence for biocycling from Ba/Ca, Sr/Ca, and 87Sr/86Sr in soils (Red Brown Earths) from South Australia." Soil Research 47, no. 2 (2009): 154. http://dx.doi.org/10.1071/sr08026.
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The impact of elemental cycling and biological fractionation in the soil–vegetation system was investigated for 6 Red Brown Earth soil profiles (Xeralfs and Xerults) from South Australia by comparing geochemical and 87Sr/86Sr data from bulk soils, soil exchange pool, and vegetation (grapes). In all 6 soil profiles from 3 different sites, Ba/Ca ratios of vegetation, soil exchange pool, and bulk soils were found to be a more robust biological fractionation indicator than Sr/Ca ratios. In the base-poor soils of the Coonawarra–Padthaway area of South Australia, the degree of weathering of soil material, as estimated by titania and alumina contents, correlated very well with the biological fractionation indicator Ba/Ca. Soil horizons with greater clay and titania content also had higher degrees of biological fractionation. Similar Red Brown Earth soils 400 km north in the Clare Valley showed either no, or poor, biological fractionation signature in their bulk soil. The Clare Valley soils have a stronger colluvial component and are richer in base cations than the Coonawarra and Padthaway sites. The main source of bulk soil material in the base-poor soils of the Coonawarra–Padthaway areas is dust, which has greatly influenced the base cation concentration, Ba/Ca ratios, and the strontium isotope ratios. Soils from Clare Valley, by comparison, are less intensely weathered and are thus not as dependent on dust and biocycling for their base cations. Biological fractionation has not left a discernible signature on the composition of the bulk soil. The exchange pools at all 3 sites are dominated by wetfall–dryfall sources, which in this coastal area are dominated by marine sources. For the base-poor soils of the Coonawarra–Padthaway area, the most likely major source of aeolian detritus is Murray River mud. The fine-grained component of this mud, with its organic matter content, relatively high base cation concentrations, and low strontium isotope ratios (Douglas et al. 1995) appears to have overwhelmed other dust sources and caused a homogenisation of the geochemical signature of fine-grained bulk soils in this area. Subsequent in situ weathering and neoformation following dust deposition were strongly influenced by exchange phase concentrations and ratios and resulted in an enhanced biological fractionation signature of the soils.
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Gillman, G. P. "An analytical tool for understanding the properties and behaviour of variable charge soils." Soil Research 45, no. 2 (2007): 83. http://dx.doi.org/10.1071/sr06117.
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Routine analyses for soil cation exchange properties usually give only limited insight into the properties and management of soils containing significant amounts of variable charge. In this paper a procedure for determining a soil Charge Fingerprint is fully described, a model developed from simplified theory to underpin the methodology is discussed, and examples of the usefulness of the approach are given. Operationally defined cation and anion exchange capacities (CEC and AEC) are determined over an appropriate pH range (pH 4 to pH 6 is suggested) using Ca and Cl as the index cations. At low pH, Ca does not always fully saturate the CEC, so that it is necessary to distinguish a Basic CEC (Ca ads.) from the Total CEC (Ca + Al ads.). The graphical representation of CECT, CECB, and AEC v. pH constitutes the Charge Fingerprint. Though not intended as a routine instrument, its determination on key samples in a characterisation exercise places routinely determined basic and acidic cations in context. Examples are given of large scale characterisation studies that link soils from different continents having similar surface charge characteristics; of the assessment of the success or otherwise of producing permanent positive charge in synthetically prepared Ti-substituted goethites; and of the evaluation of the effect of adding crushed basic rock amendment on the surface charge properties of a variable charge soil. The formulation of a Depreciation Index, which classifies soils in terms of their departure in basic cation content from an arbitrarily defined ‘ideal’ condition, is suggested for use in soil resource assessment.
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Tucker, BM. "A proposed new reagent for the measurement of cation exchange properties of carbonate soils." Soil Research 23, no. 4 (1985): 633. http://dx.doi.org/10.1071/sr9850633.
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A solution of choline chloride (1 mol L-1) in aqueous ethanol (65% by weight) is proposed as a reagent for extracting double-layer exchangeable cations from soils containing calcium carbonate, instead of the previously used solution of NH4Cl (1 mol L-1) at pH 8.5 in aqueous ethanol. This choline chloride reagent gives better estimates of double-layer exchangeable cations and of double-layer charge (exchange capacity) because it dissolves less CaCO3, and reacts less with specifically adsorbed forms of Ca, Mg and K than the NH4Cl reagent does. Because plants can use both adsorbed and exchangeable cations, the new reagent is not suitable for measuring nutrient cation availabilities. Cation exchange values for a range of Australian carbonate soils are presented to show the differences to be expected between analyses by the choline chloride and the NH4Cl reagents.
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Jayawardane, N. S., E. W. Christen, M. Arienzo, and W. C. Quayle. "Evaluation of the effects of cation combinations on soil hydraulic conductivity." Soil Research 49, no. 1 (2011): 56. http://dx.doi.org/10.1071/sr09222.
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Effects of soil solution cation concentrations and ratios on hydraulic properties must be understood in order to model soil water flow in reactive soils or develop guidelines for sustainable land application of wastewater. We examined effects of different ratios and concentrations of the cations Ca2+, Mg2+, Na+, and K+, using hydraulic conductivity measurements in repacked soil cores, as an indicator of soil structural stability. We examined widely used indices—sodium, potassium, and monovalent cation absorption ratios (SAR, PAR, MCAR)—which assume that the flocculating effects of Ca2+ and Mg2+ are the same, and the dispersive effects of Na+ and K+ are the same. Our laboratory measurements indicate that at any given values of MCAR, the reductions in soil hydraulic conductivity with decrease in electrolyte concentration are not identical for different cation combinations in solution. The hydraulic conductivity curves showed a marked lateral shifting for both the surface and subsurface soils from a winery wastewater application site. This indicates that MCAR is inadequate as a soil stability parameter in soil solutions containing a mixture of Na+, K+, Ca2+, and Mg2+. We employed an unpublished equation that was proposed by P. Rengasamy as a modified index of soil stability for mixed cation combinations, using calculated relative flocculating powers of different cations (‘CROSS’, cation ratio of structural stability). Our observation of lateral shift in hydraulic conductivity measurements at any value of MCAR appears to relate to changes in CROSS values for all cation combinations tested, except for K–Mg solutions, for which a more generalised CROSS equation with modified parameters seems more suitable for calculating the CROSS value. Appropriate modified parameters for use in this generalised CROSS equation were determined empirically, using the experimental data. We derived a combination of threshold electrolyte concentration and CROSS values required to maintain high hydraulic conductivity for the soils at a winery wastewater application site. The potential use of this relationship in developing management practices for sustainable wastewater management at the site is discussed. Further research on the applicability of CROSS and generalised CROSS equations for other soils in the presence of different mixed cation combinations is needed.
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Krishnan, Kavinraj, Audrey Awing Ngerong, Karen Ahim, Osumanu Haruna Ahmed, Maru Ali, Latifah Omar, and Adiza Alhassan Musah. "Mitigating Potassium Leaching from Muriate of Potash in a Tropical Peat Soil Using Clinoptilolite Zeolite, Forest Litter Compost, and Chicken Litter Biochar." Agronomy 11, no. 10 (September 22, 2021): 1900. http://dx.doi.org/10.3390/agronomy11101900.
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Using muriate of potash (MOP) as a source of potassium (K) is a cost-effective method for crop production in tropical peat soils. However, exchangeable K commonly leaches from tropical peat soils because of high rainfall and a lack of clay to retain this cation. Potassium retention as exchangeable K could inhibit K loss through leaching to increase K availability. Clinoptilolite zeolite (CZ), forest litter compost (FLC), and chicken litter biochar (CLB) can be used to retain K from MOP in tropical peat soils for crop use because of the high affinity of CZ, FLC, and CLB for K ions. These approaches can be used as innovative and sustainable alternatives for the frequently used lime (CaCO3). However, information on using CZ, FLC, and CLB for MOP K retention is limited. Thus, CZ, FLC, and CLB were tested in a leaching study to determine their effects on MOP K retention in tropical peat soil. The use of CZ and FLC at rates of 100% and 75% of the recommended rate for pineapple cultivation (a commonly grown fruit crop in tropical peat soils in Malaysia) improved the K availability, pH, and CEC of the peat soil because of the high CEC of CZ and the humic substances (humic acids, fulvic acids, and humin) of FLC, which have a high affinity for K ions. The CLB did not improve K retention because of the competition between K, Ca, Mg, and Na ions, which are inherently high in this soil amendment. Instead of liming, which only replaces a few of the leached cations, such as calcium, the results of this study suggest an alternative method of retaining peat cations, such as K, that reduce peat acidity. This alternative method of retaining peat soil cations, especially K ions, is a practical and sustainable approach for improving peat soil productivity.
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Zimmermann, Stephan, Andreas Chervet, Claudia Maurer, and Wolfgang G. Sturny. "Säurestatus und Versauerungszustand von Waldböden im Kanton Bern | State of acidification and sensitivity to acidification of forest soils in the canton of Bern." Schweizerische Zeitschrift fur Forstwesen 161, no. 12 (December 1, 2010): 524–29. http://dx.doi.org/10.3188/szf.2010.0524.
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The state of acidification of the soil and the sensitivity to further acidification of 238 forest soils in the canton of Bern are assessed by means of the pH-value and the exchangeable cations. Summing up all criteria of the assessment allows the building of seven classes of forest soils with increasing state of acidification, decreasing base saturation and cation exchange capacity and increasing risk for further acidification (decrease in pH-value and base saturation, increase in potential Al-toxicity). This assessment allows the identification of soils which are vulnerable to a fast further acidification and which are especially appropriate to be monitored in future in an environmental monitoring system.
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Fonseca, Adriel Ferreira da, Luís Reynaldo Ferracciú Alleoni, Adolpho José Melfi, and Célia Regina Montes. "Cation exchange capacity of an oxisol amended with an effluent from domestic sewage treatment." Scientia Agricola 62, no. 6 (December 2005): 552–58. http://dx.doi.org/10.1590/s0103-90162005000600007.
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The addition of Na-rich anthropogenic residues to tropical soils has stimulated the scientific community to study the role of sodium in both the soil solution and the exchange complex. In this study, several different methods were used to calculate the concentration of exchangeable and soluble cations and this data was then used to establish correlations between the level of these cations and both the accumulation of various elements and the dry weight of maize grown in a greenhouse under different conditions. In the closed environments of the pots, the most suitable method for calculating the effective cation exchange capacity (ECEC) was the cation exchange capacity calculated by cations removed with barium chloride solution (CEC S). Then again, the actual cation exchange capacity (CEC A) should be measured by using Mg adsorption to prevent ionic force from influencing electric charges. A strong positive correlation was obtained between the concentrations of Na in the 1:2 soil:water extracts and the accumulation of Na in the maize plants, indicating saline or double acid extractors are not needed when monitoring the Na concentration only.
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Vladimír, Šimanský, Kolenčík Marek, and Puškelová L'ubica. "Effect of Carbonates and Bivalent Cations and Their Relationships with Soil Organic Matter from the View Point of Aggregate Formation." Agriculture (Pol'nohospodárstvo) 60, no. 3 (December 10, 2014): 77–86. http://dx.doi.org/10.2478/agri-2014-0009.
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Abstract The effect of carbonates on soil structure has not been sufficiently studied yet, despite the fact that in the literature their positive impact is mentioned mostly. Carbonates are the source of bivalent cations in soil solution and may be involved in stabilization of the aggregates, because negatively charged organic materials can be adsorbed onto the surface of clay by bivalent or polyvalent cations. We studied the effect of carbonates and bivalent cations and their relationships with soil organic matter (SOM) from the point of view of aggregate formation. The studies were carried out in several fields located on loamy Calcaric Chernozem, loamy Haplic and Mollic Fluvisols. The results showed that between exchangeable Mg2+ and water-stable macro-aggregates (WSAma) in size fractions >2 mm, positive correlations were found; however, the content of Mg2+ negative correlated with the contents of WSAma in <1 mm fractions as well as with waterstable micro-aggregates (WSAmi). The threshold limit for Mg2+ content for the formation of water-stable macro-aggregates was at 11.5 cmol/kg if all loamy soils were assessed together. A further increase resulted in a lower content of WSAma. If all investigated soils were assessed separately, these results did not enable us to distinguish the maximum formation of WSAma by Mg2+ in individual soils. We observed a positive correlation between the sum of basic exchangeable cations (SBC) as well as between cation exchange capacity (CEC) and larger size fractions of WSAma >2 mm; however, between SBC as well as CEC and smaller size fractions of WSAma >1 mm and WSAmi negative correlations were observed. Statistically significant negative correlations were observed between SOM content in WSA and carbonate content, and this effect was stronger in relation to the labile carbon. There were also positive correlations between SOM in WSA and SBC and CEC found if all loamy soils were assessed together.
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Ouimet, Rock, and Louis Duchesne. "Base cation mineral weathering and total release rates from soils in three calibrated forest watersheds on the Canadian Boreal Shield." Canadian Journal of Soil Science 85, no. 2 (May 1, 2005): 245–60. http://dx.doi.org/10.4141/s04-061.
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Total release rates of base cations (Ca, Mg, K, and Na) from soils and from watersheds were evaluated using three methods. Three methods, one of which is new, were also used to evaluate mineral weathering rates of soils for three calibrated forest watersheds in the forest ministry’s monitoring network (Réseau d’étude et de surveillance des eco ystems forestiers: Quebec Forest Ecosystem Research and Monitoring Network; RESEF) on the Canadian Boreal Shield. We also compiled an extensive literature review of forest soil base cation release rates, focussed on northeastern North American forest soils of granitic lithology. With the exception of the total release and mineral weathering of Ca from soils at the Lake Laflamme Watershed site, and the total release of K from the three watersheds, soils and watershed release rates for the three watersheds were within the confidence interval of release rates compiled for forest ecosystems with similar granitic environment (compiled data for solum [mmol (+) m-2 yr-1 ± 95% CI], Ca: 33.8 ± 16.3, Mg: 16.8 ± 4.2, K: 13.0 ± 5.6, Na: 11.1 ± 3.0, and sum of base cations (BC): 61.2 ± 11.0; compiled data from watersheds, Ca: 82.8 ± 24.6, Mg: 50.8 ± 17.0, K: 7.8 ± 2.2, Na: 44.7 ± 12.8, and BC: 186.0 ± 49.9). Given the uncertainties associated with the calculations, there was little overall difference between total release rates and weathering release rates from soils for two of the three watersheds. Key words: Weathering rate, forest soil, granitic environment, watershed, PMB method, compositional trends
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Carmona, Felipe de Campos, Ibanor Anghinoni, Marquel Jonas Holzschuh, and Marcelo Hoerbe Andrighetti. "Cation dynamics in soils with different salinity levels growing irrigated rice." Revista Brasileira de Ciência do Solo 34, no. 6 (December 2010): 1851–63. http://dx.doi.org/10.1590/s0100-06832010000600009.
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Salinity levels in soils of the Outer Coastal Plain of Rio Grande do Sul, Brazil, can be high, due to excess of Na in the irrigation water, evapotranspiration and soil development from marine sediments. The cultivation of irrigated rice could be an alternative, since ion uptake as well as leaching by the establishment of a water layer could mitigate the effects of soil salinity. This study aimed to evaluate the dynamics of basic cations in the solution of Albaqualf soils with different salinity levels growing irrigated rice. The plow layer contained exchangeable Na percentages (ESP) of 5.6, 9.0, 21.2 and 32.7 %. The plant stand, dry matter, Na, K and Ca + Mg uptake at full flowering and grain yield were evaluated. The levels of Na, K, Ca + Mg and electrical conductivity (EC) in the soil solution were also measured weekly during the rice cycle at four soil depths, in the water layer and irrigation water. The Na, K and Ca + Mg uptake by rice at full flowering was used to estimate ion depletion from the layer under root influence. Soil salinity induced a reduction in the rice stand, especially in the soil with ESP of 32.7 %, resulting in lower cation uptake and very low yield at that site. As observed in the water layer and irrigation water, the Na, K, Ca + Mg and EC levels in the soil solution decreased with time at depths of 5, 10 and 20 cm, regardless of the original soil salinity, showing that cation dynamics in the plow layer was determined by leaching and root uptake, rather than by the effect of evapoconcentration of basic cations in the soil surface layer.
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Mackenzie, D. E., and A. G. Christy. "The role of soil chemistry in wine grape quality and sustainable soil management in vineyards." Water Science and Technology 51, no. 1 (January 1, 2005): 27–37. http://dx.doi.org/10.2166/wst.2005.0004.
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This study aimed to establish if there is any evidence that soil mineralogical and/or chemical composition influence the composition and quality of wine grapes. In the initial phase of the study, soils and grapes were sampled in two riesling vineyards in South Australia. Soils were analysed for a wide range of total major and trace elements; soil cation extracts and grape juices were analysed for 27 trace elements by ICP-MS and ICP-AES. The results show that grape juice properties such as Baumé and titratable acidity (TA) are clearly correlated with several plant-available trace elements in the soil. Most notable of these are Ca, Sr, Ba, Pb and Si. Soil clay content also plays a (lesser) role. The cations Ca, Sr, Ba and Pb are closely similar to one another in their relationships to Baumé and TA, strongly indicating that the correlations are real. It is evident from our results that soil cation chemistry does indeed have an influence on wine grape composition. Such knowledge has the potential to be used in better tailoring grape varieties to soils, and in managing – or modifying – soils for optimum viticultural results and better wines in a more sustainable way.
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Hochman, Z., DC Edmeades, and E. White. "Changes in effective cation exchange capacity and exchangeable aluminum with soil pH in lime-amended field soils." Soil Research 30, no. 2 (1992): 177. http://dx.doi.org/10.1071/sr9920177.
Full textAbstract:
Eleven acidic soils from northern N.S.W., having a wide range of values for ECEC, A1 and soil organic carbon (%C), were treated in the field with five rates of lime. The relationships between soil pH and the effective cation exchange capacity (ECEC), and between pH and exchangeable aluminium (Al), were investigated for the top 10 cm of these soils. Increases in the total exchangeable cations (TEC) calculated as ECEC-Al, were shown to be madelup almost entirely by increases in exchangeable calcium. There were no consistent changes in the amount of exchangeable magnesium, potassium or sodium due to liming these acidic soils. Formulae used to predict changes in A1 and ECEC with pH in the 'Lime-it' model were tested and modified on the 11 soils from northern N.S.W. A strong linear relationship was observed in each soil between Al and pH (transformed to hydrogen ion concentration x 103). The slope of this relationship (SALs) can be predicted from the pH and A1 values of unlimed soils. Strong linear relationships were also observed between pH and TEC, for each of the 11 soils. The SL, (the slope of the linear relationship TEC/pH for any soil 's') was shown by multiple regression analysis to be a function of TECi/pHi (where TECi is the sum of exchangeable cations of unlimed soil 's'; and pHi is the pH value of unlimed soil 's'), %C of the unlimed soil, and SALs. By using the measured values of pH, ECEC, Al and %C of unlimed soils, the values of Al, and TEB can be predicted for any pH value that may be measured (or predicted) after liming. The predictive relationships developed on N.S.W. soils were tested against independent data from New Zealand. The results confirmed the Al/pH predictions (R2 = 0.955), while the TEC/pH predictions were less well matched (R2= 0.62) possibly due to unusual clay mineralogy or organic matter fractions of 3 of the 18 soils tested.
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Conyers, Mark, and Graeme Poile. "Simultaneous measurement of exchangeable Al and other cations in acidic soils." Soil Research 56, no. 5 (2018): 503. http://dx.doi.org/10.1071/sr18049.
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It is both time consuming and costly to undertake two extractions of acidic soils when there is a need to measure exchangeable Al along with the other cations. There is some evidence that, although 1 M KCl is the standard procedure for exchangeable Al, the extraction of soil with 0.1 M BaCl2 + 0.1 M NH4Cl gives similar values. It would then be possible to measure all cations from one extraction. There is also concern that the assumption of trivalence of Al does not hold true in all situations, as commonly held to be true in the literature of the 1950s to the 1970s. Two experiments were conducted: the first a simple comparison of three extraction procedures in common use in New South Wales and the second a repeated comparison of two extractions but with more detailed measurements to enable interpretation of the results. During the second experiment we also measured the charge on the extracted Al by titration. The three methods for extraction of Al gave similar results despite very different procedures with respect to physical mixing, soil–solution contact time and strength of electrolyte, indicating that the pool of exchangeable Al was operationally well defined. The average charge on KCl-extracted Al was within error of 3 moles per mole of Al, supporting the current trivalent model of Alex. The 0.1 M BaCl2 + 0.1 M NH4Cl procedure estimated Alex successfully on acid soils of low effective cation exchange capacity (ECEC) (<10 cmolc/kg) and so can be used for extraction of all cations. However, as ECEC increased the 0.1 M BaCl2 + 0.1 M NH4Cl extraction tended to underestimate Alex compared with KCl on soils with above ~1.5 to 2 cmolc/kg of Alex.
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Rasmussen, Pat E., Sherry L. Schiff, and H. Wayne Nesbitt. "The determination of exchangeable cations in acid soils: Errors caused by weathering reactions during neutral salt extraction." Canadian Journal of Soil Science 71, no. 2 (May 1, 1991): 155–63. http://dx.doi.org/10.4141/cjss91-015.
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To investigate pH-controlled chemical reactions associated with the neutral salt measurement of exchangeable cations in acid soils, and to estimate the potential error caused by such reactions, a series of experiments was performed which modify an established BaCl2 extraction method. Results showed that dissolution of amorphous silica, aluminum hydroxides and organic material occurs during neutral salt extraction, contributing cations to solution which are indistinguishable from exchangeable cations. As a result overestimates of exchangeable Al and Ca occur, but the error is not significant (> 10%) except in certain Ae horizons which are low in total CEC and high in exchangeable acidity. The 2-h BaCl2 method is recommended over the 4-hour NaCl method to minimize interference from weathering reactions. Key words: Cation exchange, exchangeable acidity, Al, H, acid forest soils, weathering
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Hartikainen, Helinä. "Soil response to acid input in a titration experiment." Agricultural and Food Science 1, no. 6 (December 1, 1992): 577–85. http://dx.doi.org/10.23986/afsci.72470.
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Cultivated surface soil samples of an acid Gleysol (soil 1, pH 4.9) and a slightly acid Podzol (soil 2, pH 6.7) were equilibrated for 48 h with oto 144 meq H+ kg-1 by a batch technique designed to simulate reactions of acid load with soil constituents. The pH of the titration suspensions ranged in soil 1 from 5.6 to 3.3, in soil 2 from 7.2 to 4.7. The exchange reaction with base cations on variable charge sites was an important mechanism for H+ inactivation. The quantities of cation equivalents released were, however, lower than the proton equivalents added. Calcium dominated the supernatant solutions, but as related to exchangeable reserves. Mg seemed to be more susceptible to acidification at high soil pH. Protons were also consumed in the mobilization of divalent base cations from a non-exchangeable pool to an exchangeable one. The experimental soils differed in their response of acid cation fractions to proton loading. In the rather neutral soil 2, the quantities of soluble and exchangeable acid cations were very low and not affected by acidification. The Al dissolved by proton attack was immobilized by complexation reactions. This mechanism did not operate in the acid soil 1 where the proton loading markedly increased the exchangeable Al pool and, consequently, the soluble Al in the supernatant solution. This was associated with a simultaneous reduction in the complexed Al and a small increase in complexed Fe. Furthermore, acidification diminished the effective cation exchange capacity (ECEC) decisively less in soil 1 than in soil 2, because the increase in exchangeable Al markedly compensated the reduction in the exchangeable base cations. As compared to freelydrained systems, the batch titration overestimated the release of Al to solution phase.
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Malla, R., K. Mori, and K. L. Totawat. "Effect of municipal sewage on chemical build-up in soils and vegetables." Water Supply 7, no. 4 (December 1, 2007): 79–85. http://dx.doi.org/10.2166/ws.2007.093.
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A mini-lysimeter study conducted showed that use of lower dilution of sewage water improved the physico-chemical properties and nutrient status of the soils but resulted higher per cent build up of metallic cations in them, particularly Zn, Pb and Ni in sandy clay loam soil and Cu and Cd in sandy loam soil. Indian spinach (Beta vulgaris var. bengalensis) irrigated with lower dilution of sewage water improved OC content of the soils, while cauliflower (Brassica oleracea L.) and carrot (Daucus carota L.) decreased the CaCO3 content. Metallic cations content in the leaves and roots of the crops increased when irrigated with lower dilution sewage water but the level of metallic cations contamination was quite below the maximum permissible limits suggested. However, contamination of the soils and phyto-toxicity cannot be ruled out if such sewage irrigation is used on long-term basis.
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Soto, B., and F. Diaz-Fierros. "Interactions Between Plant Ash Leachates and Soil." International Journal of Wildland Fire 3, no. 4 (1993): 207. http://dx.doi.org/10.1071/wf9930207.
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We studied a) leaching of Ulex, Pinus and Eucalyptus ashes; b) leaching from the surface layer (0 - 5 cm) of 6 types of soil subjected to thermal shock at a range of temperatures equivalent to those reached in a wildfire (25-degrees-C to 700-degrees-C); and c) leaching of Ulex, Pinus and Eucalyptus ashes through a subsurface soil layer not subjected to thermal shock. Element release from plant ashes and heat-treated soils was highly dependent on the solubility of the principal chemical forms in which that element occurred. The monovalent cations Na and K, largely present as chlorides and carbonates, were mobilized much more rapidly than the divalent cations Ca and Mg, largely present as oxides and carbonates. Element release from heat-treated soil was also dependent on shock temperature. The monovalent cations were extensively mobilized following shocks at less than 380-degrees-C, and the divalent cations following higher-temperature shocks. These differences appear to be related to element volatilization and mineralization of organic matter. The subsurface soil not subjected to thermal shock showed a tendency to retain the elements released from plant ashes and from heat-treated surface soil. The subsurface layers may also release hydrogen ions and organic matter, as a result of cation exchange and dissolution processes respectively.
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Niu, Yuan Yuan, Shi Chen Zhou, Xue Ying Tan, Ping Xu, and Dong Li. "Influence of Cations in Anolytes on the Power Efficiency in the Electrokinetic Remediation of Chromium(VI)-Contaminated Soils." Advanced Materials Research 414 (December 2011): 106–10. http://dx.doi.org/10.4028/www.scientific.net/amr.414.106.
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In the electrokinetic (EK) remediation of contaminated soils, the ions in porous fluid move out of soil and meanwhile the ions in electrolytes move in, resulting in the changes of soil conductance and remediation efficiency. This paper investigated the influence of different cations on the power efficiency of EK remediation of chromium-contaminated soils with Fe2+, Ca2+, H+, K+, and Na+ ions. Results showed that the cations of low equivalent ionic conductance can effectively decrease the power consumption meanwhile not deteriorating the removal rate of total chromium.
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Khanna, PK, RJ Raison, and RA Falkiner. "Exchange characteristics of some acid organic rich forest soils." Soil Research 24, no. 1 (1986): 67. http://dx.doi.org/10.1071/sr9860067.
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The cation exchange characteristics were determined for several acid organic-rich soils formed under sub-alpine eucalypt forests growing in the Australian Capital Territory. Most of the exchange sites in the red and yellow earths studied are occupied by Al and are associated with soil organic matter. Unbuffered salt solutions extract more Al than could be associated with exchange sites, so that the sum of cations in the extracts is an overestimate of the effective cation exchange capacity (CECe). The CECe is not a unique property but depends upon pH and ionic strength (I) of the equilibrating solution. The exchange sites mainly carry negative charges of both permanent and variable nature. Higher carbon contents of the soils are correlated with increases in CECe due to increasing I, and with greater negative charge due to increasing pH. Some modifications to the compulsive exchange method of Gillman for determining CECe are proposed for its use with acid organic-rich soils.
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Isichei, Augustine Onwuegbukiwe, and Joseph Ikechukwu Muoghalu. "The effects of tree canopy cover on soil fertility in a Nigerian savanna." Journal of Tropical Ecology 8, no. 3 (August 1992): 329–38. http://dx.doi.org/10.1017/s0266467400006623.
Full textAbstract:
ABSTRACTThe effect of tree canopy cover on soil properties was studied over three periods: middry season (January), mid-growth period (August) and peak-growth period (October) in three 1 ha plots in savanna of north-west Nigeria. The objective was to find out whether tree canopies change the nutrient status of the soil under them relative to adjacent grasslands. Soils under tree canopies were found to have significantly higher levels of organic matter, calcium, magnesium, potassium, total exchangeable bases, cation exchange capacity and pH than those in open grasslands. Nitrogen and phosphorus were slightly higher in soils under tree canopies than those in the open grasslands. Trees 7 m and above had more influence on soil properties than smaller trees. Differences in soil properties among the study plots were due to differences in their soil texture. Seasonal trends were observed in organic matter, carbon: nitrogen ratio, cation exchange capacity, phosphorus, calcium, sodium, total exchangeable cations and percentage base saturation.