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Adsorption Ratio (adsorption + ratio)
Kinds of Adsorption Ratio Selected AbstractsA diminished capacity for chloride exclusion by grapevine rootstocks following long-term saline irrigation in an inland versus a coastal region of AustraliaAUSTRALIAN JOURNAL OF GRAPE AND WINE RESEARCH, Issue 3 2006J.M. TREGEAGLE Abstract Shiraz and Chardonnay grapevines that had been initially assessed for Cl - exclusion in the 1996 and 1997 harvest seasons at both Merbein (inland region of Victoria) and at Padthaway (sub-coastal region of South Australia), were re-evaluated in 2003 and 2004 at those same two locations. Both scion varieties were grown either on their own roots or were grafted to one of the following rootstocks: Ramsey, 1103 Paulsen, 140 Ruggeri, K51-40, Schwarzmann, 101-14, Rupestris St George and 1202 Couderc. Both sites had been irrigated with saline water since 1994. The salinity of irrigation water at Merbein was approximately 2.1 dS/m; at Padthaway irrigation salinity varied between approximately 1.6 dS/m and 2.5 dS/m during the survey period. Changes in the Cl - -excluding ability of all rootstock/scion combinations between 1996, 1997 and 2003, 2004 were based upon analysis of Cl - concentrations in grape juice and in laminae at harvest, as well as Electrical Conductivity (EC), pH and Sodium Adsorption Ratio (SAR) of the 1:5 soil:water extract. Taking juice Cl - as indicative of rootstock effectiveness for Cl - exclusion, and considering data from Merbein, our analyses demonstrated that overall means for Shiraz juice Cl - increased from around 190 to 427 mg/L over the survey period (7 years). In Chardonnay grapevines at Merbein, overall mean concentrations of Cl - in juice increased from around 70 to around 225 mg/L over 7 years. Significant differences between rootstocks were evident, with some rootstocks at Merbein showing a diminished capacity for Cl - exclusion in 2003 and 2004. By contrast, in Padthaway there was no consistent deterioration in Cl - -excluding capacity by rootstocks supporting either Shiraz or Chardonnay as scions. In 2004 there were significant differences between grapevines at Merbein and Padthaway in the concentration of Cl - accumulated, even though the mean soil EC1:5 after harvest for 0,90 cm depth was the same at both sites, namely 0.4 dS/m. Containment of grapevine salinity at Padthaway (relative to Merbein) between 1996/97 and 2003/04 was most likely due to factors such as a lower volume of saline irrigation, double the rainfall and 27% lower pan evaporation. [source] The role of mineralogy, geochemistry and grain size in badland development in Pisticci (Basilicata, southern Italy)EARTH SURFACE PROCESSES AND LANDFORMS, Issue 7 2007V. Summa Abstract Mineralogical, geochemical and grain-size composition of soil and pore-water chemistry parameters were characterized on both eroded (south-facing) and non-eroded (north-facing) clayey-silt slopes in the Basilicata region (southern Italy). Only a few grain-size parameters and clay mineralogy discriminate eroded from non-eroded substrates. Compared with the latter, the former have fractions of over 63 µm and 1,4 µm lower and fractions 4,63 µm higher. Grain-size characters of crusts did not discriminate with respect to substrate. Bulk rock mineralogy was not distinctive, but the clay mineral assemblage shows that the eroded slope is enriched in kaolinite, mixed layers (illite,smectite) and chlorite, whereas illite decreases, although overlaps are common. Chemical data enable discrimination between eroded and non-eroded slopes. pH, SAR (sodium adsorption ratio), TDS (total dissolved salts) and PS (percentage of sodium) are distinctive parameters for both eroded and non-eroded slopes. TDS increases in depth in the non-eroded slope, whereas the maximum TDS is just below the crust in the eroded one. On average, eroded substrates are higher in pH, SAR and PS than non-eroded ones. The ESP (exchangeable sodium percentage) of the eroded slope has a higher value than the non-eroded one. Crusts are less dispersive than eroded substrates, and non-eroded substrates behave as crusts. This suggests that the portion of the slope most severely exposed to weathering tends to stabilize, due to strong decreases in SAR, PS and ESP. Several diagrams reported in the literature show similarly anomalous crust samples on eroded slopes, compared with other samples coming from greater depths on eroded slopes. In the present case study, the exchangeable form of Na characterizes crusts more than the soluble form. This study describes the erosional mechanism, which involves morphological and geographic exposure and climatic elements, as well as grain size, mineralogy, chemistry and exchangeable processes of soils. Copyright © 2006 John Wiley & Sons, Ltd. [source] Elementary processes of soil,water interaction and thresholds in soil surface dynamics: a reviewEARTH SURFACE PROCESSES AND LANDFORMS, Issue 9 2004Richard S. B. Greene Abstract Elementary processes of soil,water interaction and the thresholds to these processes are important to understand as they control a range of phenomena that occur at the soil surface. In particular processes involved with wetting by rainfall that lead to particle breakdown are critical. This breakdown causes soil detachment and crust formation, which are both key elements in erosion. This paper reviews the range of approaches that have been taken in describing the processes associated with the wetting of a soil surface by rainfall. It assembles the studies that emphasize soil physics, soil chemistry, and erosion mechanics in a framework to enable a balanced consideration of important processes and management strategies to control erosion for a particular situation. In particular it discusses the factors associated with the two basic processes of soil structural breakdown, i.e. slaking and dispersion, and how these processes are critical in particle detachment, transport and surface crust formation. Besides the balance between the exchangeable cation composition and electrolyte concentration (measured as the sodium adsorption ratio (SAR) and total cation concentration (TCC) respectively) of the soil, the importance of energy input and soil organic matter content in controlling clay dispersion is emphasized. Based on the balance between these factors, the soil can be in one of three different regions, i.e. a dispersed region, a ,occulated region and one where the resilience of the soil is variable. The implications of each of these regions to soil erosion management are brie,y outlined, as are the critical roles that soil cover levels and organic matter have in controlling erosion. Finally, the relationship between various laboratory measures of aggregate stability, and corresponding ,eld erosion characteristics, is discussed. Copyright © 2004 John Wiley & Sons, Ltd. [source] Effect of ionic strength and clay mineralogy on Na,Ca exchange and the SAR,ESP relationshipEUROPEAN JOURNAL OF SOIL SCIENCE, Issue 5 2006P. M. Kopittke Summary The relationship between sodium adsorption ratio (SAR) and exchangeable sodium percentage (ESP) for all soils has traditionally been assumed to be similar to that developed by the United States Salinity Laboratory (USSL) in 1954. However, under certain conditions, this relationship has been shown not to be constant, but to vary with both ionic strength and clay mineralogy. We conducted a detailed experiment to determine the effect of ionic strength on the Na+,Ca2+ exchange of four clay minerals (kaolinite, illite, pyrophyllite, and montmorillonite), with results related to the diffuse double-layer (DDL) model. Clays in which external exchange sites dominated (kaolinite and pyrophyllite) tended to show an overall preference for Na+, with the magnitude of this preference increasing with decreasing ESP. For these external surfaces, increases in ionic strength were found to increase preference for Na+. Although illite (2:1 non-expanding mineral) was expected to be dominated by external surfaces, this clay displayed an overall preference for Ca2+, possibly indicating the opening of quasicrystals and the formation of internal exchange surfaces. For the expanding 2:1 clay, montmorillonite, Na+,Ca2+ exchange varied due to the formation of quasicrystals (and internal exchange surfaces) from individual clay platelets. At small ionic strength and large ESP, the clay platelets dispersed and were dominated by external exchange surfaces (displaying preference for Na+). However, as ionic strength increased and ESP decreased, quasicrystals (and internal exchange surfaces) formed, and preference for Ca2+ increased. Therefore, the relationship between SAR and ESP is not constant and should be determined directly for the soil of interest. [source] Effects of oxidation time on the structure and properties of polyacrylonitrile-based activated carbon hollow fiberJOURNAL OF APPLIED POLYMER SCIENCE, Issue 1 2007Junfen Sun Abstract Polyacrylonitrile (PAN) hollow fibers were pretreated with ammonium dibasic phosphate, then further oxidized in air, carbonized in nitrogen, and activated with carbon dioxide. The effects of oxidation time of PAN hollow fiber precursor on the microstructure, specific surface, pore size distribution, and adsorption properties of PAN-based activated carbon hollow fiber (PAN-ACHF) were studied in this work. Both of specific surface area and adsorption ratio to VB12 reach maximums when PAN hollow fibers are oxidized for 5 h in air. The adsorption ratios for creatinine are all higher than 90% over all oxidation time. After 5 h of oxidation, the number of pores on the surface obviously increases, and the pore size is uniform. After 7 h of oxidation, the number of macropores in PAN-ACHF increases. The dominant pore sizes of mesopores in PAN-ACHF range from 2 to 5 nm. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007 [source] Proton release by N2 -fixing plant roots: A possible contribution to phytoremediation of calcareous sodic soilsJOURNAL OF PLANT NUTRITION AND SOIL SCIENCE, Issue 1 2003Manzoor Qadir Prof. Dr. Abstract With a world-wide occurrence on about 560 million hectares, sodic soils are characterized by the occurrence of excess sodium (Na+) to levels that can adversely affect crop growth and yield. Amelioration of such soils needs a source of calcium (Ca2+) to replace excess Na+ from the cation exchange sites. In addition, adequate levels of Ca2+ in ameliorated soils play a vital role in improving the structural and functional integrity of plant cell walls and membranes. As a low-cost and environmentally feasible strategy, phytoremediation of sodic soils , a plant-based amelioration , has gained increasing interest among scientists and farmers in recent years. Enhanced CO2 partial pressure (PCO2) in the root zone is considered as the principal mechanism contributing to phytoremediation of sodic soils. Aqueous CO2 produces protons (H+) and bicarbonate (HCO3 - ). In a subsequent reaction, H+ reacts with native soil calcite (CaCO3) to provide Ca2+ for Na+ Ca2+ exchange at the cation exchange sites. Another source of H+ may occur in such soils if cropped with N2 -fixing plant species because plants capable of fixing N2 release H+ in the root zone. In a lysimeter experiment on a calcareous sodic soil (pHs = 7.4, electrical conductivity of soil saturated paste extract (ECe) = 3.1 dS m -1, sodium adsorption ratio (SAR) = 28.4, exchangeable sodium percentage (ESP) = 27.6, CaCO3 = 50 g kg -1), we investigated the phytoremediation ability of alfalfa (Medicago sativa L.). There were two cropped treatments: Alfalfa relying on N2 fixation and alfalfa receiving NH4NO3 as mineral N source, respectively. Other treatments were non-cropped, including a control (without an amendment or crop), and soil application of gypsum or sulfuric acid. After two months of cropping, all lysimeters were leached by maintaining a water content at 130% waterholding capacity of the soil after every 24±1 h. The treatment efficiency for Na+ removal in drainage water was in the order: sulfuric acid > gypsum = N2 -fixing alfalfa > NH4NO3-fed alfalfa > control. Both the alfalfa treatments produced statistically similar root and shoot biomass. We attribute better Na+ removal by the N2 -fixing alfalfa treatment to an additional source of H+ in the rhizosphere, which helped to dissolve additional CaCO3 and soil sodicity amelioration. Protonenabgabe durch N2 -fixierende Pflanzenwurzeln: ein möglicher Beitrag zur Phytomelioration von kalkreichen Natriumböden Bei einem weltweiten Vorkommen auf etwa 560 Millionen Hektar sind Natriumböden durch einen Überschuss an Natrium (Na+) gekennzeichnet, der das Wachstum und den Ertrag von Kulturpflanzenbeständen nachteilig beeinflussen kann. Die Melioration solcher Böden erfordert Calcium (Ca2+), um überschüssiges Na+ von Kationen-Austauscherplätzen zu verdrängen. Außerdem spielt Ca2+ eine wichtige Rolle bei der Verbesserung der strukturellen und funktionellen Integrität pflanzlicher Zellwände und Membranen. Als kostengünstige und umweltfreundliche Strategie hat die Phytomelioration von Natriumböden , eine auf Pflanzen beruhende Melioration , in den letzten Jahren zunehmendes Interesse bei Wissenschaftlern und Landwirten gefunden. Ein erhöhter CO2 -Partialdruck (PCO2) in der Rhizosphäre wird als hauptsächlicher Mechanismus angesehen, der zur Phytomelioration von Natriumböden beiträgt. In Wasser gelöst, erzeugt CO2 Protonen (H+) und Bikarbonate (HCO3 - ). Anschließend reagiert H+ mit nativem Calcit (CaCO3), wobei sich Ca2+ löst und Na+ von Austauscherplätzen verdrängt. Eine weitere H+ -Quelle könnte die H+ -Abgabe von Wurzeln N2 -fixierender Pflanzen sein, da diese in der Lage sind, H+ in die Rhizosphäre abzugeben. In einem Lysimeterversuch mit einem kalkreichen Natriumboden (pHs = 7, 4; ECe = 3, 1 dS m -1; SAR = 28, 4; ESP = 27, 6; CaCO3 = 50 g kg -1) wurde die Möglichkeit einer Phytomelioration mit N2 -fixierender Luzerne (Medicago sativa L.) im Vergleich zu einer mit mineralischem N ernährten Luzerne (NH4NO3) untersucht. In weiteren Varianten (Applikation von Gips bzw. Schwefelsäure) wurde die chemische Melioration einer nicht behandelten Kontrolle gegenübergestellt. Beide Ernährungsformen führten zu statistisch ähnlicher Wurzelund Sprossmasse der Luzerne. Nach zweimonatigem Pflanzenwachstum erfolgte alle 24±1 h eine Dränung der Lysimeter durch Zugabe einer Wassermenge von 130% der maximalen Wasserkapazität zum Boden. Hinsichtlich der Effizienz, Na+ über Auswaschung aus dem Boden zu entfernen, zeigte sich folgende Reihenfolge: Schwefelsäure > Gips = N2 -fixierende Luzerne > NH4NO3 -ernährte Luzerne > Kontrolle. Wir führen das bessere Meliorationsergebnis in der Variante der N2 -fixierenden Luzerne auf eine zusätzliche H+ -Quelle in der Rhizosphäre zurück, die zur Lösung von zusätzlichem CaCO3 beitrug. [source] The use of coal fly ash in sodic soil reclamationLAND DEGRADATION AND DEVELOPMENT, Issue 3 2003D. Kumar Abstract An experiment was conducted for two years in northwest India to explore the feasibility of using coal fly ash for reclamation of waterlogged sodic soils and its resultant effects on plant growth in padi,wheat rotation. The initial pH, electrical conductivity, exchangeable sodium percentage and sodium adsorption ratio of the experimental soil were 9.07, 3.87,dS,m,1, 26.0 and 4.77 (me l),1/2, respectively. The fly ash obtained from electrostatic precipitators of thermal power plant had a pH of 5.89 and electrical conductivity of 0.88,dS,m,1. The treatments comprised of fly ash levels of 0.0, 1.5, 3.0, 4.5, 6.0 and 7.5 per cent, used alone as well as in combination with 100, 80, 60, 40, 20 and 10 per cent gypsum requirement of the soil, respectively. There was a slight reduction in soil pH while electrical conductivity of the soil decreased significantly with fly ash as measured after padi and wheat crops. The sodium adsorption ratio of the soil decreased with increasing fly ash levels, while gypsum treatments considerably added to its favourable effects. Fly ash application increased the available elemental status of N, K, Ca, Mg, S, Fe, Mn, B, Mo, Al, Pb, Ni, Co, but decreased Na, P and Zn in the soil. An application of fly ash to the soil also increased the concentrations of above elements except Na, P and Zn in the seeds and straw of padi and wheat crops. The available as well as elemental concentrations in the plants was maximum in the 0 per cent fly ash,+,100 per cent gypsum requirement treatment except Na and heavy elements like Ni, Co, Cr. The treatment effects were greater in the fly ash,+,gypsum requirement combinations as compared to fly ash alone. Saturated hydraulic conductivity and soil water retention generally improved with the addition of fly ash while bulk density decreased. Application of fly ash up to 4.5 per cent level increased the straw and grain yield of padi and wheat crops significantly in both years. The results indicated that for reclaiming sodic soils of the southwest Punjab, gypsum could possibly be substituted up to 40 per cent of the gypsum requirement with 3.0 per cent acidic fly ash. Copyright © 2003 John Wiley & Sons, Ltd. [source] Sodium removal from a calcareous saline,sodic soil through leaching and plant uptake during phytoremediationLAND DEGRADATION AND DEVELOPMENT, Issue 3 2003M. Qadir Abstract Saline,sodic and sodic soils are characterized by the occurrence of sodium (Na+) to levels that can adversely affect several soil properties and growth of most crops. As a potential substitute of cost-intensive chemical amelioration, phytoremediation of such soils has emerged as an efficient and low-cost strategy. This plant-assisted amelioration involves cultivation of certain plant species that can withstand ambient soil salinity and sodicity levels. It relies on enhanced dissolution of native calcite within the root zone to provide adequate Ca2+ for the Na+Ca2+ exchange at the cation exchange sites. There is a lack of information for the Na+ balance in terms of removal from saline,sodic soils through plant uptake and leaching during the phytoremediation process. We carried out a lysimeter experiment on a calcareous saline,sodic soil [pH of saturated soil paste (pHs),=,7.2, electrical conductivity of the saturated paste extract (ECe),=,4.9,dS,m,1, sodium adsorption ratio (SAR),=,15.9, CaCO3,=,50,g,kg,1]. There were three treatments: (1) control (without application of a chemical amendment or crop cultivation), (2) soil application of gypsum according to the gypsum requirement of the soil and (3) planting of alfalfa (Medicago sativa L.) as a phytoremediation crop. The efficiency of treatments for soluble salt and Na+ removal from the soil was in the order: gypsum,,,alfalfa,>,control. In the phytoremediation treatment, the amount of Na+ removed from the soil through leaching was found to be the principal cause of reduction in salinity and sodicity. Copyright © 2003 John Wiley & Sons, Ltd. [source] Morphologies and applied properties of PSI/PA composite particles synthesized at low temperaturePOLYMER COMPOSITES, Issue 11 2008Yumin Wu Latex with a poly(dimethyl-siloxane) core and a poly(methylmethacrylate- butylacrylate- 2-hydroxypropyl acrylate) shell have been prepared at low temperature with potassium-persulphate (KPS), sodium formaldehyde sulfoxylate (SFS) and 2,2,-azobis [2-(2-imidazolin- 2-yl)propane] dihydrochloride (VA-044) as composite initiators by staged emulsion polymerization. Reactive surfactants were used to significantly improve the applied properties such as water adsorption ratio and thermo-properties. Transmission electron microscopy (TEM) results indicated that increasing the amount of 2-hydroxypropyl acrylate (HPA) and butylacrylate (BA) was favorable to form the core/shell particles. Particle size distribution results showed with increasing the dosages of surfactants, initiators, and seed-latex, particle size decreased. Differential scanning calorimetry (DSC) and thermogravimetric analyzer (TGA) results indicated the high temperature-reserved of copolymer was improved in the presence of polysiloxane. POLYM. COMPOS., 2008. © 2008 Society of Plastics Engineers [source] | |||||||||||||