Academic literature on the topic 'Exchangeable sodium'

A good statistical relationship was obtained between the exchangeable-sodium ratio and the sodium adsorption ratio (SAR) in Brown Solonetzic and associated soils in southern Alberta. Reliable estimates of the exchangeable-sodium status of these sulfate-rich soils may be anticipated when SAR values are less than 20. Prediction of the exchangeable-sodium status of soils on the basis of SAR values is preferable for both Solonetzic soil and irrigation suitability classification. A saturation extract SAR value of five in the B horizon generally corresponds to an exchangeable calcium to sodium ratio of 10. Saturation extract SAR values of five and 12 are recommended as revised soil chemical criteria for Brown Solonetzic soil and irrigation suitability classification, respectively. Key words: Solonetzic soils, exchangeable cations, sodium adsorption ratio, selectivity coefficient, irrigation suitability

1. Chlorothiazide (100 mg/kg body weight) was given by gavage daily to spontaneously hypertensive rats for 4 weeks. Another group of spontaneously hypertensive rats was given only tap water and served as control. 2. Measurements of total exchangeable sodium, blood pressure and weight were performed for 2 weeks before and for 4 weeks during treatment. 3. Before treatment, exchangeable sodium, blood pressure and weight were similar in the two groups of rats. 4. Chlorothiazide significantly attenuated the blood pressure increase in spontaneously hypertensive rats, the effect being most marked during the first 2 1/2 weeks of treatment and less thereafter. 5. Rats in the chlorothiazide-treated group gained weight more slowly than did those of the control group. 6. Exchangeable sodium, expressed as mmol/kg body weight, did not differ significantly between the two groups at any stage. 7. When exchangeable sodium was expressed as mmol/rat, there was a more gradual rise in the chlorothiazide-treated animals, in accordance with their slower gain in weight. 8. There was no temporal association between the antihypertensive effect of chlorothiazide and changes in exchangeable sodium. 9. Thus whereas chlorothiazide treatment of spontaneously hypertensive rats slows the increase of both weight and exchangeable sodium, other mechanisms are apparently responsible for the antihypertensive action of the drug.

Sodic soils are characterised by their poor structural stability. This is thought to be caused mainly by high levels of exchangeable sodium and low electrolyte concentrations. Historically, soil sodicity has been reported as the exchangeable sodium percentage, ESP [(exchangeable Na/∑ exchangeable cations)�×�100]. However, some authors believe that exchangeable sodium content alone is a better indicator of sodicity, whereas others suggest that an effective sodicity index is one which includes both the exchangeable sodium levels and electrolyte concentration (EC1:5). Some examples are the electrochemical stability index (EC 1:5/ESP) and EC1:5/exchangeable Na. The objective of this study was to evaluate which of 3 empirical sodicity indices (ESP, EC1:5/ESP, EC1:5/exchangeable Na) was best related to soil dispersion in Vertosols sown to cotton farming systems.Soil was sampled between 1995 and 2001 from 4 irrigated and dryland sites in New South Wales and Queensland, where the cropping systems included continuous cotton (Gossypium hirsutum L.), cotton–rotation crop sequences, and 2- and 1-m beds. Tillage systems ranged from zero to minimum tillage. Soils from all sites were analysed for EC1:5, exchangeable Ca, Mg, K, and Na, and dispersion index, and ESP, EC1:5/ESP and EC1:5/exchangeable Na derived. Long-term dispersion was best predicted by EC1:5/exchangeable Na, except where zero tillage was practised when none of the sodicity indices were related to dispersion. Aggregate stabilisation under zero tillage was speculated to be determined largely by labile soil organic matter and microbial activity rather than sodicity.

Field classification of Vertosols and Sodosols in Australia involves the calculation of an exchangeable sodium percentage (ESP) of the subsoil to estimate sodicity. ESP has historically been determined by laboratory measurement of the cation exchange capacity (CEC) and exchangeable sodium. This often leads to a delay in field classification and mapping and missed extension opportunities with landholders. Recently, ion-specific electrode field meters have been developed that allow the determination of the sodium ion concentration within a soil solution. If field tests and/or calculation can estimate clay percentage and sodium concentration, there is potential for rapid field assessment of ESP. The field meter accurately predicted exchangeable sodium (R2 = 0.83). In addition CEC was related to clay percentage (R2 = 0.79). The estimated ESP calculated by the field tests compared favourably with the actual ESP measurement (R2 = 0.85).

Conselho Nacional de Desenvolvimento CientÃfico e TecnolÃgico
No Nordeste semi-Ãrido, as maiores incidÃncias de Ãreas salinizadas sÃo observadas nas terras intensamente cultivadas com o uso da irrigaÃÃo nos PerÃmetros Irrigados, sobretudo aqueles com o mÃtodo por superfÃcie. O experimento foi realizado no NÃcleo D do PerÃmetro Irrigado Curu-Pentecoste - CE. A pesquisa teve como objetivo avaliar o efeito da subsolagem do solo associada com tratamentos quÃmicos e biolÃgicos, na melhoria das condiÃÃes de transmissÃo de Ãgua no perfil do solo, de atributos fÃsicos e quÃmicos do solo, na produtividade do feijÃo-de-corda [Vigna unguiculata (L.) Walp.] cultivar Epace 11 alÃm dos indicadores de rentabilidade da recuperaÃÃo de um solo sÃdico irrigado por sulcos. Utilizou-se o delineamento experimental de blocos inteiramente casualizados com cinco tratamentos e cinco repetiÃÃes. Os tratamentos foram T0: testemunha; T1: 40 t.ha-1 de matÃria orgÃnica; T2: 20 t.ha-1 de gesso; T3: 20 t.ha-1 (gesso) +40 t.ha-1 (M.O); T4: 10 t.ha-1 (gesso) + 20 t.ha-1 (M.O). Os resultados permitiram as seguintes conclusÃes: 1. A produtividade do feijoeiro com o uso de melhoradores quÃmicos foi superior em 120% à produtividade sem o uso destes melhoradores e inferior em 18% à produtividade da cultura em solos sem problemas de salinidade do PerÃmetro. 2. As maiores produtividades do feijoeiro estÃo associadas a maiores profundidades do lenÃol freÃtico. O incremento de produtividade do feijoeiro com a profundidade do lenÃol freÃtico ocorreu a uma taxa crescente. 3. A aplicaÃÃo de 20 t.ha-1 de gesso e 40 t.ha-1 de matÃria orgÃnica proporcionou jà no primeiro ano, a reduÃÃo da percentagem de sÃdio trocÃvel do solo, inicialmente de um valor mÃdio superior a 50% para um valor convergente de 2%. 4. LimitaÃÃo quanto à cota de saÃda dos drenos laterais orientam para a instalaÃÃo do sistema de drenagem subterrÃnea do tipo intercepÃÃo, embora os gradientes hidrÃulicos mÃdios do movimento de Ãgua subterrÃnea sejam bem inferiores a 1%. 5. A taxa relacionada entre o valor bruto da produÃÃo gerado exclusivamente pela cultura do feijoeiro e o custo da recuperaÃÃo do solo, demonstra que a renda gerada pela cultura contribui em 12% com o custo da recuperaÃÃo do solo sÃdico. 6. O processo de recuperaÃÃo demonstra uma boa viabilidade a uma taxa de 12% ao ano e alta viabilidade a uma taxa de juros de 6% ao ano, revelando que a essa taxa todo o investimento realizado serà recuperado e remunerada e ainda um lucro extra igual a R$ 5.328,85.
In the semi-arid part of Northeastern Brazil, the highest incidences of salinized areas are observed in land subjected to intense irrigated cultivation, in the âPerÃmetros Irrigadosâ (irrigated perimeters), particularly those where is used the surface method. The experiment was performed in the âNÃcleo Dâ (D Core) of the âPerÃmetro Irrigado Curu-Pentecoste - Ceâ. The research aimed at evaluating the effect of the subsoiling of the treated area combined with the application of chemical and biological treatments in the same area. Specifically, it aimed at evaluating the effect of the said combination (a) in the improvement of the hydraulic properties in the profile of the soil, (b) in the improvement of the productivity of the cowpea [Vigna unguiculata (L.) Walp.] of the Epace 11 cultivar and (c) in the indicators of profitability of the recovery of a sodic soil irrigated by furrows. We used a randomized complete block experimental design with five treatments and five replications. The treatments were T0: control, T1: 40 t ha-1 of organic matter, T2: 20 t ha-1 gypsum T3: 20 t ha-1 (gypsum) + 40 t ha-1 (MO) T4: 10 t ha-1 (gypsum) + 20 t ha-1 (MO). The results allowed the following conclusions: 1) The grain yield with the use of chemical enhancers was 120% higher than the productivity without those enhancers and 18% lower than the productivity (of the same cultivation) in soils without salinity problems. 2) The highest bean yields are associated with the largest values of water table depth, the increase in grain yield with the depth of the water table occurring at a rate increasing with the same depth. 3) The application of 20 t ha-1 gypsum and 40 t ha-1 Organic matter, no later than in the first year, reduced the percentage of exchangeable sodium in the soil, from an initial average above 50% to a convergent value of 2%. 4) The limitation on the elevation of the outflow of lateral drains indicate the necessity of the installation of an underground drainage system of the interception type, even if the average hydraulic gradient of the of groundwater flow is well below 1%. 5) The rate between the gross value of production generated by the cowpea crop and the cost of remediation of soil, shows that the the crop contributes with 12% of the cost of soil sodium remediation . 6) The recovery process shows a good feasibility at a rate of 12% per year and high viability at a rate of interest of 6% per year, revealing that at that rate all the investment will be recovered and paid, plus yelding an extra profit of R$ 5,328.85.

ARAGÃO, Ana Paula Bezerra Aragão. Análise técnico-econômica da recuperação de um solo sódico no peímetro irrigado curu-pentecoste-CE. 61 f. : Dissertação (mestrado) - Universidade Federal do Ceará, Centro de Ciências Agrárias, Departamento de Engenharia Agrícola, Programa de Pós-Graduação em Engenharia Agrícola, Fortaleza-CE, 2009
Submitted by demia Maia (demiamlm@gmail.com) on 2016-06-03T13:52:15Z No. of bitstreams: 1 2009_dis_apbaraújo.pdf: 1817784 bytes, checksum: 06c51bc19c1cf56e8616ef8f1feebdc1 (MD5)
Approved for entry into archive by demia Maia (demiamlm@gmail.com) on 2016-06-03T13:52:54Z (GMT) No. of bitstreams: 1 2009_dis_apbaraújo.pdf: 1817784 bytes, checksum: 06c51bc19c1cf56e8616ef8f1feebdc1 (MD5)
Made available in DSpace on 2016-06-03T13:52:54Z (GMT). No. of bitstreams: 1 2009_dis_apbaraújo.pdf: 1817784 bytes, checksum: 06c51bc19c1cf56e8616ef8f1feebdc1 (MD5) Previous issue date: 2009
In the semi-arid part of Northeastern Brazil, the highest incidences of salinized areas are observed in land subjected to intense irrigated cultivation, in the “Perímetros Irrigados” (irrigated perimeters), particularly those where is used the surface method. The experiment was performed in the “Núcleo D” (D Core) of the “Perímetro Irrigado Curu-Pentecoste - Ce”. The research aimed at evaluating the effect of the subsoiling of the treated area combined with the application of chemical and biological treatments in the same area. Specifically, it aimed at evaluating the effect of the said combination (a) in the improvement of the hydraulic properties in the profile of the soil, (b) in the improvement of the productivity of the cowpea [Vigna unguiculata (L.) Walp.] of the Epace 11 cultivar and (c) in the indicators of profitability of the recovery of a sodic soil irrigated by furrows. We used a randomized complete block experimental design with five treatments and five replications. The treatments were T0: control, T1: 40 t ha-1 of organic matter, T2: 20 t ha-1 gypsum T3: 20 t ha-1 (gypsum) + 40 t ha-1 (MO) T4: 10 t ha-1 (gypsum) + 20 t ha-1 (MO). The results allowed the following conclusions: 1) The grain yield with the use of chemical enhancers was 120% higher than the productivity without those enhancers and 18% lower than the productivity (of the same cultivation) in soils without salinity problems. 2) The highest bean yields are associated with the largest values of water table depth, the increase in grain yield with the depth of the water table occurring at a rate increasing with the same depth. 3) The application of 20 t ha-1 gypsum and 40 t ha-1 Organic matter, no later than in the first year, reduced the percentage of exchangeable sodium in the soil, from an initial average above 50% to a convergent value of 2%. 4) The limitation on the elevation of the outflow of lateral drains indicate the necessity of the installation of an underground drainage system of the interception type, even if the average hydraulic gradient of the of groundwater flow is well below 1%. 5) The rate between the gross value of production generated by the cowpea crop and the cost of remediation of soil, shows that the the crop contributes with 12% of the cost of soil sodium remediation . 6) The recovery process shows a good feasibility at a rate of 12% per year and high viability at a rate of interest of 6% per year, revealing that at that rate all the investment will be recovered and paid, plus yelding an extra profit of R$ 5,328.85.
No Nordeste semi-árido, as maiores incidências de áreas salinizadas são observadas nas terras intensamente cultivadas com o uso da irrigação nos Perímetros Irrigados, sobretudo aqueles com o método por superfície. O experimento foi realizado no Núcleo D do Perímetro Irrigado Curu-Pentecoste - CE. A pesquisa teve como objetivo avaliar o efeito da subsolagem do solo associada com tratamentos químicos e biológicos, na melhoria das condições de transmissão de água no perfil do solo, de atributos físicos e químicos do solo, na produtividade do feijão-de-corda [Vigna unguiculata (L.) Walp.] cultivar Epace 11 além dos indicadores de rentabilidade da recuperação de um solo sódico irrigado por sulcos. Utilizou-se o delineamento experimental de blocos inteiramente casualizados com cinco tratamentos e cinco repetições. Os tratamentos foram T0: testemunha; T1: 40 t.ha-1 de matéria orgânica; T2: 20 t.ha-1 de gesso; T3: 20 t.ha-1 (gesso) +40 t.ha-1 (M.O); T4: 10 t.ha-1 (gesso) + 20 t.ha-1 (M.O). Os resultados permitiram as seguintes conclusões: 1. A produtividade do feijoeiro com o uso de melhoradores químicos foi superior em 120% à produtividade sem o uso destes melhoradores e inferior em 18% à produtividade da cultura em solos sem problemas de salinidade do Perímetro. 2. As maiores produtividades do feijoeiro estão associadas a maiores profundidades do lençol freático. O incremento de produtividade do feijoeiro com a profundidade do lençol freático ocorreu a uma taxa crescente. 3. A aplicação de 20 t.ha-1 de gesso e 40 t.ha-1 de matéria orgânica proporcionou já no primeiro ano, a redução da percentagem de sódio trocável do solo, inicialmente de um valor médio superior a 50% para um valor convergente de 2%. 4. Limitação quanto à cota de saída dos drenos laterais orientam para a instalação do sistema de drenagem subterrânea do tipo intercepção, embora os gradientes hidráulicos médios do movimento de água subterrânea sejam bem inferiores a 1%. 5. A taxa relacionada entre o valor bruto da produção gerado exclusivamente pela cultura do feijoeiro e o custo da recuperação do solo, demonstra que a renda gerada pela cultura contribui em 12% com o custo da recuperação do solo sódico. 6. O processo de recuperação demonstra uma boa viabilidade a uma taxa de 12% ao ano e alta viabilidade a uma taxa de juros de 6% ao ano, revelando que a essa taxa todo o investimento realizado será recuperado e remunerada e ainda um lucro extra igual a R$ 5.328,85.

Sodium titanate materials which have a layered structure consisting of titanate layers and exchangeable sodium ions are promising inorganic ionic exchangers for strontium adsorption from aqueous solution. The materials used in this study include samples synthesized in a hydrothermal method at different temperatures between 60°C and 200°C. Batch kinetics experiments for strontium removal from aqueous solution were performed. Kinetics data were fitted by using a pseudo second order reaction model and a diffusive model. It was shown that the sorption process occurs in one or two diffusion-controlled steps that depend on the synthesis temperature. The strontium extraction capacity depends on the synthesis temperature with a maximum for sample synthesis at 100°C. This sample has good properties of decontamination at laboratory scale.

The laboratory experiment was done that 1.0mol/L sodium hydroxide solution was injected to the compacted bentonite whose density is the same as the prospected value in the concept of the intermediate-level disposal in Japan in the circumstance of 70°C temperature. After the injection of the alkali solution for approximately 600 days, the bentonite was taken out of the apparatus and some sorts of analysis were done. The accompanying minerals in the bentonite, calcedony and quartz, were dissolved and disappeared in XRD charts. Then analcime was precipitated as a secondary mineral. Although montmorillonite was dissolved, the mass fraction of it was kept approximately. The hydraulic conductivity of the bentonite calculated using the flow rate at the end of the injection of alkali solution was smaller than the prospected value based on a widely-used empirical model of the hydraulic conductivity of compacted bentonite as a function of the equivalent concentration of pore solution, montmorillonite partial void ratio, and the ratio of sodium ion equivalent to the exchangeable cation equivalent. The reasons for the difference were supposed to be the decrease of pore size brought by mineral dissolution and the large viscosity of pore solution involving high concentration aqueous silicon.