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Jiulan Dai - One of the best experts on this subject based on the ideXlab platform.
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adsorption and desorption of iodine by various chinese soils ii iodide and iodate
Geoderma, 2009Co-Authors: Jiulan Dai, Min Zhang, Yujuan Huang, Renqing Wang, Yongguan ZhuAbstract:Abstract It is important to understand iodine availability in various soils in China to efficiently manage and control environmental iodine. A series of batch experiments was conducted on a variety of Chinese soils in order to determine the adsorption characteristics of iodide and iodate. For five soils, the sorption isotherms of iodide were determined, while for all 17 soils, iodide adsorption was studied under one initial concentration to evaluate its sorption capacity. Furthermore, iodate sorption isotherms on two soils at five different initial concentrations were determined in this study, to complement the earlier work of Dai et al. (2004a). From the sorption isotherm results, five Chinese soils were ranked in terms of their capacity for iodate adsorption: Perudic Ferrisols soil, HN > Orthic Aridisols soil, XJ1 > Udic Ferrisols soil, JX2 > Usdic Luvisols soil, BJ > Udic Isohumisols soil, JL. As a comparison, iodide adsorption was ranked as follows: Udic Ferrisols soil, JX2 > Perudic Ferrisols soil, HN > Udic Isohumisols soil, JL > Usdic Luvisols soil, BJ > Orthic Aridisols soil, XJ2. It was also found that the desorbed amounts demonstrated a significant positive correlation with the adsorption of the XJ1 and BJ soils for iodate, and also did the HN and JX2 soils for iodide. At an initial iodide concentration of 4 mg L− 1, the values of the sorption distribution coefficient, Kd, ranged between 0.78 and 6.59 mg kg− 1 soil in 17 soils from China, and iodide adsorption was significantly correlated with soil organic matter and cation exchange capacity. Kd exhibited a linear relationship with soil organic matter, a polynomial relationship with free iron oxide content and a logarithmic relationship with cation exchange capacity. Furthermore, results from iodate and iodide adsorption from 17 Chinese soils, except for Fimic Anthrosols soil (GX) showed that the adsorption capacities of iodate were greater than those of iodide, and organic matter in soil environments plays an important role in controlling iodine geochemistry.
Patrick Francisco Fuhr - One of the best experts on this subject based on the ideXlab platform.
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Iterrelation of palaeosols and sediment in the ancient Marilia Formation aeolian sand sheets (northwestern Bauru Basin)
2017Co-Authors: Patrick Francisco FuhrAbstract:Resumo: A Formação Marília (Maastrichtiano), na faixa de afloramentos da porção noroeste da Bacia Bauru (estados de Goiás e Mato Grosso do Sul), é interpretada neste trabalho como um antigo sistema eólico de lençol de areia. A sucessão vertical é caracterizada por arenitos muito finos a médios intercalados com paleossolos em espessas sucessões de até 150 metros de espessura. A litofácies Arenito com laminação plano-paralela, que forma corpos com estratificação cavalgante transladante subcrítica, atribuída à deposição de areias com marcas onduladas eólicas é a mais comum descrita na área de estudos. Os paleossolos representam mais de 65% do registro geológico da Formação Marília, constituídos predominantemente por Aridisols caracterizados por concentrações secundárias de carbonato de cálcio. Superfícies suborizontais de deflação eólica separam os depósitos eólicos dos paleossolos e dividem a Formação Marília em duas fases distintas de construção de corpos geológicos ligadas às variações paleoclimáticas: i) fase de sedimentação eólica, caracterizada por depósitos arenosos de marcas onduladas eólicas; ii) fase de paleopedogênese, caracterizada por Aridisols. Ambas as fases se alternaram temporalmente e, registram períodos de formação de diferentes ordens de grandeza, provavelmente maiores que 105 vezes entre a formação dos depósitos arenosos com marcas onduladas eólicas e o desenvolvimento de horizontes Bk dos Aridisols. A alternância cíclica entre depósitos eólicos e paleossolos está ligada a variações paleoclimáticas que controlaram a disponibilidade hídrica no ambiente. Durante os períodos mais secos, a ausência de cobertura vegetal expôs a superfície à ação dos ventos e formação de extensas superfícies de deflação eólica, que posteriormente foram cobertas por depósitos arenosos de marcas onduladas eólicas. Com o posterior restabelecimento da umidade atmosférica e o conseqüente aumento da cobertura vegetal, a superfície foi reestabilizada, inibindo o processo de deflação e deposição eólica e permitindo a formação de Entisols e Aridisols.Abstract: The Marília Formation (Maastrichtian), outcropping in the northwestern portion of the Bauru Basin (Goiás and Mato Grosso do Sul brazilian states), is interpreted here as an ancient Aeolian sand sheet. The vertical succession, c.150 m thick, is made up of very fine to medium-grained sandstone and, it is characterised by cyclic interbedding of sediments and palaeosols. Planar laminated sandstone (subcritically climbing translatent stratification), formed by aeolian sand with wind ripple, is the most common lithofacies. Palaeosols, mainly Aridisols, represent more than 65% of the geological record of the Marília Formation. Subhorizontal aeolian deflation surfaces divide Marília Formation in two distinct constructional phases of geological bodies linked to palaeoclimatic variations: i) phase of prevalent aeolian sand deposition; ii) phase of Aridisols development. The two phases they alternated in time and probably record periods of formation with difference of the order greater than 105 between aeolian sand deposition and development of the Bk Aridisols horizons. Palaeoclimate is the main forcing factor of the Aeolian sand deposition and soil development. Episodes of sedimentation and soil development likely result from cyclic decreases and increases in available moisture and vegetation cover. Aeolian deflation and sedimentation were predominant during drier phases of past climatic cycles, when vegetation cover was sparse in source areas and windier conditions have the capacity to remove and transport clastic materials. During wetter phases of climatic cycles, increased vegetative cover stabilised the landscape, reduced deflation, and intensified Entisols and Aridisols development
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Iterrelation of palaeosols and sediment in the ancient Marilia Formation aeolian sand sheets (northwestern Bauru Basin)
Universidade Estadual de Campinas . Instituto de Geociências, 2008Co-Authors: Patrick Francisco FuhrAbstract:A Formação Marília (Maastrichtiano), na faixa de afloramentos da porção noroeste da Bacia Bauru (estados de Goiás e Mato Grosso do Sul), é interpretada neste trabalho como um antigo sistema eólico de lençol de areia. A sucessão vertical é caracterizada por arenitos muito finos a médios intercalados com paleossolos em espessas sucessões de até 150 metros de espessura. A litofácies Arenito com laminação plano-paralela, que forma corpos com estratificação cavalgante transladante subcrítica, atribuída à deposição de areias com marcas onduladas eólicas é a mais comum descrita na área de estudos. Os paleossolos representam mais de 65% do registro geológico da Formação Marília, constituídos predominantemente por Aridisols caracterizados por concentrações secundárias de carbonato de cálcio. Superfícies suborizontais de deflação eólica separam os depósitos eólicos dos paleossolos e dividem a Formação Marília em duas fases distintas de construção de corpos geológicos ligadas às variações paleoclimáticas: i) fase de sedimentação eólica, caracterizada por depósitos arenosos de marcas onduladas eólicas; ii) fase de paleopedogênese, caracterizada por Aridisols. Ambas as fases se alternaram temporalmente e, registram períodos de formação de diferentes ordens de grandeza, provavelmente maiores que 105 vezes entre a formação dos depósitos arenosos com marcas onduladas eólicas e o desenvolvimento de horizontes Bk dos Aridisols. A alternância cíclica entre depósitos eólicos e paleossolos está ligada a variações paleoclimáticas que controlaram a disponibilidade hídrica no ambiente. Durante os períodos mais secos, a ausência de cobertura vegetal expôs a superfície à ação dos ventos e formação de extensas superfícies de deflação eólica, que posteriormente foram cobertas por depósitos arenosos de marcas onduladas eólicas. Com o posterior restabelecimento da umidade atmosférica e o conseqüente aumento da cobertura vegetal, a superfície foi reestabilizada, inibindo o processo de deflação e deposição eólica e permitindo a formação de Entisols e Aridisols.The Marília Formation (Maastrichtian), outcropping in the northwestern portion of the Bauru Basin (Goiás and Mato Grosso do Sul brazilian states), is interpreted here as an ancient Aeolian sand sheet. The vertical succession, c.150 m thick, is made up of very fine to medium-grained sandstone and, it is characterised by cyclic interbedding of sediments and palaeosols. Planar laminated sandstone (subcritically climbing translatent stratification), formed by aeolian sand with wind ripple, is the most common lithofacies. Palaeosols, mainly Aridisols, represent more than 65% of the geological record of the Marília Formation. Subhorizontal aeolian deflation surfaces divide Marília Formation in two distinct constructional phases of geological bodies linked to palaeoclimatic variations: i) phase of prevalent aeolian sand deposition; ii) phase of Aridisols development. The two phases they alternated in time and probably record periods of formation with difference of the order greater than 105 between aeolian sand deposition and development of the Bk Aridisols horizons. Palaeoclimate is the main forcing factor of the Aeolian sand deposition and soil development. Episodes of sedimentation and soil development likely result from cyclic decreases and increases in available moisture and vegetation cover. Aeolian deflation and sedimentation were predominant during drier phases of past climatic cycles, when vegetation cover was sparse in source areas and windier conditions have the capacity to remove and transport clastic materials. During wetter phases of climatic cycles, increased vegetative cover stabilised the landscape, reduced deflation, and intensified Entisols and Aridisols development
Yongguan Zhu - One of the best experts on this subject based on the ideXlab platform.
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adsorption and desorption of iodine by various chinese soils ii iodide and iodate
Geoderma, 2009Co-Authors: Jiulan Dai, Min Zhang, Yujuan Huang, Renqing Wang, Yongguan ZhuAbstract:Abstract It is important to understand iodine availability in various soils in China to efficiently manage and control environmental iodine. A series of batch experiments was conducted on a variety of Chinese soils in order to determine the adsorption characteristics of iodide and iodate. For five soils, the sorption isotherms of iodide were determined, while for all 17 soils, iodide adsorption was studied under one initial concentration to evaluate its sorption capacity. Furthermore, iodate sorption isotherms on two soils at five different initial concentrations were determined in this study, to complement the earlier work of Dai et al. (2004a). From the sorption isotherm results, five Chinese soils were ranked in terms of their capacity for iodate adsorption: Perudic Ferrisols soil, HN > Orthic Aridisols soil, XJ1 > Udic Ferrisols soil, JX2 > Usdic Luvisols soil, BJ > Udic Isohumisols soil, JL. As a comparison, iodide adsorption was ranked as follows: Udic Ferrisols soil, JX2 > Perudic Ferrisols soil, HN > Udic Isohumisols soil, JL > Usdic Luvisols soil, BJ > Orthic Aridisols soil, XJ2. It was also found that the desorbed amounts demonstrated a significant positive correlation with the adsorption of the XJ1 and BJ soils for iodate, and also did the HN and JX2 soils for iodide. At an initial iodide concentration of 4 mg L− 1, the values of the sorption distribution coefficient, Kd, ranged between 0.78 and 6.59 mg kg− 1 soil in 17 soils from China, and iodide adsorption was significantly correlated with soil organic matter and cation exchange capacity. Kd exhibited a linear relationship with soil organic matter, a polynomial relationship with free iron oxide content and a logarithmic relationship with cation exchange capacity. Furthermore, results from iodate and iodide adsorption from 17 Chinese soils, except for Fimic Anthrosols soil (GX) showed that the adsorption capacities of iodate were greater than those of iodide, and organic matter in soil environments plays an important role in controlling iodine geochemistry.
Aruani, María C. - One of the best experts on this subject based on the ideXlab platform.
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Equilibrio vegetativo-productivo en cultivares de vid sobre suelos con capas endurecidas, Alto Valle de Río Negro, Región Vitivinícola Sur de Argentina
Instituto de Investigaciones Agropecuarias INIA, 2013Co-Authors: Echenique, María Del C., Apcarian Alicia, Reeb Pablo, Aruani, María C.Abstract:The aim of this work was to evaluate the vegetative-productive balance of Vitis vinifera L., cvs. Merlot, Malbec and Cabernet Sauvignon on Aridisols with hardened layers in the Alto Valle of Rio Negro, Argentina. The study was carried out in 15.5 ha of vineyards during 2002-2003 on five soil groups characterized by: type, thickness and depth of the horizons, texture and resistance to penetration. In each sampling site three plants were evaluated. Production, leaf area, pruning material, trunk diameter, the Ravaz Index, the leaf area/yield ratio and the leaf area index were determined. A variance analysis and means comparison were made. The production level, the leaf area and the pruning material of the three cultivars were reduced (P < 0.05) when the soils presented extremely hard horizons (resistance to penetration greater than 3 MPa) at a depth of 35 cm or less and with 30 cm or more of thickness, indicating a low site potential. The Ravaz Index and the leaf area/yield ratio didn't show differences (P < 0.05) among soil groups in any cultivar. In soils with restricted properties, but with an adequate growth-yield balance, smaller vine spacing and avoiding gaps between vines can be used to increase production.El objetivo de este trabajo fue evaluar el equilibrio vegetativo-productivo de Vitis vinifera L. cvs. Merlot, Malbec y Cabernet Sauvignon sobre Aridisoles con capas endurecidas del Alto Valle de Río Negro, Argentina. El estudio se realizó en 15,5 ha de viñedos durante la temporada 2002-2003 sobre cinco grupos de suelos, caracterizados por: tipo, espesor y profundidad de los horizontes, textura y resistencia a la penetración. En cada sitio de muestreo, se evaluaron tres plantas para cada uno de ellos, determinando: producción, área foliar, peso del material de poda por planta, diámetro de tronco, índice de Ravaz, relación área foliar/peso de la producción e índice de área foliar. Se efectuó un análisis de varianza y una comparación de medias de las variables del cultivo según cada grupo de suelos. El nivel de producción, el área foliar y el peso de material de poda por planta de los tres cultivares resultaron disminuidos cuando los suelos presentaron horizontes extremadamente duros (resistencia a la penetración superior a 3 MPa) a menos de 35 cm de profundidad y con espesores mayores a 30 cm, indicando un bajo potencial vitícola de estos suelos. El índice de Ravaz y la relación área foliar/peso de la producción no mostraron diferencias (P < 0,05), manteniéndose relaciones de equilibrio vegetativo-productivo similares entre los grupos de suelos, aunque éstos implicaran diferentes potenciales vitícolas. En suelos con propiedades limitantes, pero con un adecuado balance vegetativo-productivo, se pueden utilizar menores espaciamientos entre cepas y evitar brechas o espacios vacíos para incrementar los rendimientos por hectárea
Rainer Schulin - One of the best experts on this subject based on the ideXlab platform.
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neural network models to predict cation exchange capacity in arid regions of iran
European Journal of Soil Science, 2005Co-Authors: M Amini, Karim C Abbaspour, H Khademi, Nader Fathianpour, M Afyuni, Rainer SchulinAbstract:Summary Design and analysis of land-use management scenarios requires detailed soil data. When such data are needed on a large scale, pedotransfer functions (PTFs) could be used to estimate different soil properties. Because existing regression-based PTFs for estimating cation exchange capacity (CEC) do not, in general, apply well to arid areas, this study was conducted (i) to evaluate the existing models and (ii) to develop neural network-based PTFs for predicting CEC in Aridisols of Isfahan in central Iran. As most researches have found a significant correlation between CEC and soil organic matter content (OM) and clay content, we also used these two variables for modelling of CEC. We tested several published PTFs and developed two neural network algorithms using multilayer perceptron and general regression neural networks based on a set of 170 soil samples. The data set was divided into two subsets for calibration and testing of the models. In general, the neural network-based models provided more reliable predictions than the regression-based PTFs.