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Search Results: 1 - 10 of 5880 matches for " Ingrid;Vidal-Torrado "
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Pedological and isotopic relations of a highland tropical peatland, Mountain Range of the Espinha?o Meridional (Brazil)
Horák, Ingrid;Vidal-Torrado, Pablo;Silva, Alexandre Christófaro;Pessenda, Luiz Carlos Ruiz;
Revista Brasileira de Ciência do Solo , 2011, DOI: 10.1590/S0100-06832011000100004
Abstract: the evolution of organic matter sources in soil is related to climate and vegetation dynamics in the past recorded in paleoenvironmental quaternary deposits such as peatlands. for this reason, a histosol of the mineralotrophic peatland from the pau-de-fruta special protection area - spa, espinha?o meridional, state of minas gerais, was described and characterized to evidence the soil constituent materials and properties as related to changes in environmental conditions, supported by the isotopic and elementary characterization of soil c and n and 14c ages. samples were collected in a depression at 1,350 m asl, where histosols are possibly more developed due to the great thickness (505 cm). nowadays, the area is colonized by vegetation physiognomies of the cerrado biome, mainly rocky and wet fields (campo rupestre and campo úmido), aside from fragments of semidecidual seasonal forest, called cap?es forests. the results this study showed that early the genesis of the analyzed soil profile showed a high initial contribution of mostly herbaceous organic matter before 8,090 ± 30 years bp (14c age). in the lower-mid holocene, between 8,090 ± 30 years ap (14c age) to ± 4,100 years bp (interpolated age), the vegetation gradually became more woody, with forest expansion, possibly due to increased humidity, suggesting the existence of a more woody cerrado in the past than at present. drier climate conditions than the current were concluded ± 2,500 years bp (interpolated age) and that after 430 years bp (14c age) the forest gave way to grassland, predominantly. after the dry season, humidity increased to the current conditions. due to these climate fluctuations during the holocene, three decomposition stages of organic matter were observed in the histosols of this study, with prevalence of the most advanced (sapric), typical of a deposit in a highly advanced stage of pedogenetic evolution.
Turfeiras da Serra do Espinha?o Meridional - MG: II - influência da drenagem na composi??o elementar e substancias húmicas
Silva, Alexandre Christófaro;Horák, Ingrid;Vidal-Torrado, Pablo;Cortizas, Antonio Martinez;Racedo, Jose Rodrigues;Campos, José Ricardo da Rocha;
Revista Brasileira de Ciência do Solo , 2009, DOI: 10.1590/S0100-06832009000500031
Abstract: peat bogs are organosols formed under ideal ecological conditions in terms of the accumulation of organic material, controlled by geomorphological and geological processes and climate. the physical, chemistry and biological constitution of peat bogs is largely unknown. in this study the peat bogs of the southern serra do espinha?o (minas gerais, brazil) were described and sampled from three profiles at 1,250 m (p1), 1,350 m (p4) and 1,800 m (p2) above sea level. the three profiles were characterized morphologically, the collected samples were chemically analyzed and the organic matter was fractioned in humin, fulvic and humic acids. the organic matter of the peat bog profiles differed strikingly in chemical composition and contents of humic substances and in the chemical composition of humic acids. the variations in drainage conditions were mostly responsible for the qualitative and quantitative differentiation of organic matter. in peat bog p1, with moderate drainage, the c/n and o/c ratios of the organic matter were higher, fulvic acid predominant among the humic substances and humic acids had a higher c/n ratio. in the peat bog p2 and p4, with very poor drainage, c/n and o/c ratios were lower in the organic matter, humin largely predominant among humic substances and c/n ratios in humic acids were lowest.
Turfeiras da Serra do Espinha?o Meridional - MG: I - caracteriza??o e classifica??o
Silva, Alexandre Christófaro;Horák, Ingrid;Cortizas, Antonio Martinez;Vidal-Torrado, Pablo;Racedo, Jose Rodrigues;Grazziotti, Paulo Henrique;Silva, Enilson de Barros;Ferreira, Celmo Aparecido;
Revista Brasileira de Ciência do Solo , 2009, DOI: 10.1590/S0100-06832009000500030
Abstract: peat bogs are a special environment for studies related with the dynamics of organic matter, landscape evolution and climatic changes and with local, regional and global cycles of atmospheric pollution. peat bogs contribute to the global c sequestration, act as water reservoirs and are the habitat of an endemic biodiversity. the serra do espinha?o meridional (minas gerais state, brazil) - sdem - a terrestrial biosphere reservation area, contains a considerably large area with different types of peat bogs, which were described in three profiles at 1,250, 1,800 and 1,350 m above sea level and classified, respectively, as organosol haplic sapric terric (p1), organosol haplic fibric typical (p2) and organosol haplic hemic typical (p4), in agreement with the brazilian system of soil classification. the three profiles were characterized morphologically and the samples were chemically, physically and microbiologically analyzed. it was found that the location, altitude and drainage influenced the morphologic, physical, chemical, and biological properties of the peat bogs in sdem. the decomposition state of organic matter is more advanced when the drainage in the peat bogs is better. the amount of heavy metals is related with the quantity and granulometric composition of the mineral fraction and location of the peat bogs. the highest mean levels of ti, zr, pb were detected in profile p1, highest mean levels of mn, zn and cu in p2, and the highest mean fe content in p4. the intensity of microbiological activity in the peat bogs p2 and p4 was related with the drainage and heavy-metal content of its layers.
Caracteriza??o morfológica, micromorfológica e físico-hídrica de solos com horizonte B nítico
Cooper, Miguel;Vidal-Torrado, Pablo;
Revista Brasileira de Ciência do Solo , 2005, DOI: 10.1590/S0100-06832005000400011
Abstract: the structure, consistence, porosity, clay films, hydraulic conductivity, and water retention of soils with nitic horizons and soils with both nitic and ferralic horizons were studied in-depth with the objective of contributing to the ongoing discussion on problems with the classification of "nitossolos" (nitisols) in brazil. the hydrophysical performance of the studied horizons is intimately related to the soil structure type and grade and to the amount and distinctness of the clay films. horizons characterized as nitic ("b nítico") presented strong or moderate subangular blocky structures and moderate and abundant to moderate and common clay films. these morphological attributes determined a low development of structural pores (macropores) and, consequently, lower hydraulic conductivity values and a higher development of textural pores (micropores) that favor water retention processes. on the other hand, horizons classified as ferralic ("b latossólico") are formed by a moderate or weak subangular blocky structure, with or without the presence of granular structure, and no or faint common clay s-kins. horizons with these morphological attributes present highly developed structural pores (macropores) that favor water conducing processes (high hydraulic conductivity) and less developed textural pores (micropores) diminishing water retention characteristics.
Caracteriza??o e gênese de perfis plínticos desenvolvidos de arenito do Grupo Bauru: II - mineralogia
Coelho, M. R.;Vidal-Torrado, P.;
Revista Brasileira de Ciência do Solo , 2003, DOI: 10.1590/S0100-06832003000300011
Abstract: in northern and western landscapes of s?o paulo state, plinthite and petroplinthite are features observed commonly above the cretaceous adamantina formation sandstones (bauru group). two representative soil profiles with plinthic, petroplinthic and mottling features were selected in the local landscape to evaluate the mineralogical characteristics and to study their formation. the study was carried out at the foot of a mountainside in the experimental station pindorama of the agronomic institute campinas (iac), in the north of s?o paulo state, brazil. scanning microscopy and pontual microanalysis of selected glaebules, as well as the mineralogical analyses of the ironfree clay fraction and the iron oxides of all studied soil profiles were carried out. it was concluded that the main clay fraction minerals of the nodules and the soil are kaolinite, hematite, and goethite. mica, gibbsite, and anatase also contribute to the mineralogy of the clay fraction of these glaebules, being similar in composition to the surrounding soil material of the profiles. the silt and sand fraction of the nodules is composed by quartz, potassium feldspars, traces of sodium feldspars, and ilmenite. the constant presence of weatherable minerals in the petroplinthic glaebules clearly indicates that the formation of these features was related to iron segregation in the saprolite. this phenomenon, associated with low levels of aluminum in the structure of the glaebules iron oxides suggests their formation under hydromorphic conditions. the hydromorphic environment is probably related to the solubilization and mobilization of ferrous iron that was removed from the upper landscape and precipitated into the vadose zone, where oxidative conditions were favorable for iron segregation and precipitation.
Caracteriza??o e gênese de perfis plínticos desenvolvidos de arenito do Grupo Bauru: I - química
Coelho, M. R.;Vidal-Torrado, P.;
Revista Brasileira de Ciência do Solo , 2003, DOI: 10.1590/S0100-06832003000300010
Abstract: plinthite and petroplinthite are commonly present features in soils developed on sandstone of the bauru group, adamantina formation, in the northern and western region of s?o paulo state. the objective of this study was to evaluate chemical properties as well as pedogenic processes that led to the formation of these materials and the soil profile. two soils at the foot of a representative mountainside of the local landscape with plinthic, petroplinthic and mottling features were selected within areas of the experimental station pindorama of the agronomic institute campinas (iac), in the north of s?o paulo state. based on pedological routine analyses, selective dissolution, and x-ray fluorescence, the predominantly oxidic origin of the glaebules was diagnosed. these gleabules are not associated with organic compounds, contain low amounts of manganese, and higher levels of poor crystalline iron in the plinthites than in the petroplinthites. main pedogenic processes that affected chemical characteristics of the saprolitic horizons in the studied profiles are: segregation and precipitation of high amounts of iron; mechanisms of eluviation-iluviation of clay and iron compounds, the ferrolysis; degradation of the petroplinthic horizons releasing iron to originate underlying plinthite.
Gênese de ferri-argil?s em horizontes B texturais de uma seqüência de solos sobre diabásio em Piracicaba (SP)
Cooper, Miguel;Vidal-Torrado, Pablo;
Scientia Agricola , 2000, DOI: 10.1590/S0103-90162000000400024
Abstract: the formation of ferriargillans and densing processes were studied on a soil sequence over diabase situated in piracicaba (sp) brazil. morphological, micromorphological, scanning electron microscopic and microanalytical studies were performed on samples taken from three trenches within the sequence. the presence of illuvial ferriargillans was observed mainly in the argillic b horizons and the saprolite, which filled the mamelonar, polyconcave and planar voids which led to their densing. evidence of temporary hydromorphy suggested that this process would affect the stability of the iron oxide-clay interactions which would promote the mobilization and redistribution of iron and clay.
Caracteriza o e gênese de perfis plínticos desenvolvidos de arenito do Grupo Bauru: I - química
Coelho M. R.,Vidal-Torrado P.
Revista Brasileira de Ciência do Solo , 2003,
Abstract: Plintita e petroplintita s o fei es de ocorrência comum nos solos desenvolvidos de arenitos do Grupo Bauru, Forma o Adamantina, nas regi es norte e oeste do estado de S o Paulo. Com o objetivo de avaliar os atributos químicos, bem como os processos pedogenéticos envolvidos na forma o desses materiais e dos perfis onde ocorrem, foram estudados dois solos da baixa meia encosta de uma vertente representativa da paisagem local, constituída por fei es plínticas, petroplínticas e mosqueados. O estudo foi realizado na Esta o Experimental de Agronomia de Pindorama do Instituto Agron mico de Campinas (IAC), regi o norte do estado de S o Paulo. Com base nas análises pedológicas de rotina, dissolu es seletivas e fluorescência de raios-X, constatou-se a origem predominantemente oxídica das glébulas estudadas, n o associadas a compostos organicos, com baixos teores de manganês e maiores conteúdos de ferro pouco cristalino nas plintitas, comparativamente às petroplintitas. A segrega o e precipita o de ferro em massa, os mecanismos de eluvia o-iluvia o das argilas e compostos de ferro, a ferrólise, bem como a degrada o dos horizontes petroplínticos, liberando ferro para a forma o da plintitas sotopostas, correspondem aos principais processos pedogenéticos atuantes nos perfis estudados, os quais influenciam sobremaneira os atributos químicos dos horizontes saprolíticos dos perfis plínticos.
Caracteriza o e gênese de perfis plínticos desenvolvidos de arenito do Grupo Bauru: II - mineralogia
Coelho M. R.,Vidal-Torrado P.
Revista Brasileira de Ciência do Solo , 2003,
Abstract: Nas paisagens do norte e oeste do estado de S o Paulo, plintita e petroplintita constituem fei es que se repetem com freqüência sobre os arenitos cretácicos da Forma o Adamantina (Grupo Bauru). Com o objetivo de avaliar as características mineralógicas desses materiais e estudar sua gênese, selecionaram-se dois perfis de solos representativos da paisagem local e constituídos por fei es plínticas, petroplínticas e mosqueados. O estudo foi realizado na baixa meia encosta de uma vertente situada na Esta o Experimental de Agronomia de Pindorama, do Instituto Agron mico (IAC), regi o norte do estado de S o Paulo. Com base nas observa es em microscópio de varredura e microanálise pontual realizadas em glébulas selecionadas, bem como nas análises mineralógicas da fra o argila desferrificada e dos óxidos de ferro de todos os horizontes dos perfis estudados, constatou-se que caulinita, hematita e goethita s o os principais constituintes da fra o argila dos nódulos e horizontes estudados. Os minerais mica, gibbsita e anatásio complementam a mineralogia da fra o argila das glébulas, assemelhando-se em constitui o ao material interglebular e aos demais horizontes dos perfis. Quartzo, feldspatos potássicos, tra os de feldspatos sódicos e ilmenita foram identificados como componentes da fra o silte e areia dos nódulos. A presen a constante de minerais alteráveis nas glébulas petroplínticas é evidência de que a gênese desses materiais está relacionada com a ferruginiza o do saprolito. Este fato, associado aos baixos teores de Al na estrutura dos óxidos de ferro das glébulas, evidencia sua forma o em condi es hidromórficas, supostamente relacionadas com a solubiliza o e mobiliza o do ferro ferroso, lixiviado da paisagem a montante e reprecipitado na zona de vadosa, onde os maiores potenciais de oxida o favoreceram a segrega o e a precipita o do ferro.
Gênese de ferri-argil s em horizontes B texturais de uma seqüência de solos sobre diabásio em Piracicaba (SP)
Cooper Miguel,Vidal-Torrado Pablo
Scientia Agricola , 2000,
Abstract: Numa sequência de solos sobre diabásio localizada no campus da USP em Piracicaba a forma o de ferri-argil s e os processos de adensamento foram estudados. Foram realizados estudos morfológicos, micromorfológicos, de microscopia eletr nica de varredura e microanálise em amostras retiradas de três trincheiras localizadas nesta sequência. A presen a de ferri-argil s de iluvia o foi observada nos horizontes B textural e na alterita principalmente preenchendo a porosidade mamelonar, polic ncava e fissural provocando o adensamento dos mesmos. Evidências de hidromorfia temporária sugeriram que este processo estaria provocando a desestabiliza o das liga es ferro-argila facilitando assim a mobiliza o e redistribui o do ferro e da argila.
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