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The micromorphology of deeply weathered soils (Ferralsols/Latossolos) from the Central Plateau of Brazil remains little studied, and its affiliation to different parent materials, poorly known. To clarify the processes of soil formation of these acric, gibbsitic, Fe-oxide rich Ferralsols, three lithotoposequences on local ultrabasic to basic intrusive rocks were studied. The influences of mixing and pedobioturbation are evident in all soils, and Ferralsols of the Central Plateau of Brazil are polygenetic, based on the coarse mineral composition, with ultrabasic and metapelitic rock contributions. The typical oxic microstructure with stable microaggregates encompasses a gibbsite/Fe rich micromass with random inclusions of charcoal, allochthonous quartz, Ti-magnetite, and perovskite grains. Shallow Cambisols (Cambissolos) on tuffites also display a similar 'oxic' microstructure, but a much lower degree of weathering. These Cambisols possesses apatite, and mafic and pelitic minerals as residuals minerals grains, indicating the polygenetic colluvia mixture of different substrates. The common occurrence of perovskite (CaTiO3) as a residual grain in deep-weathered, acric Ferralsols on ultrabasic rocks, not yet reported in the literature, shows an unusual resistant Ca reserve in oxic soils, though nothing is known about its implications to soil fertility. Made available in DSpace on 2019-09-28T00:48:30Z (GMT). No. of bitstreams: 1 Micromorphologyandgenesisofsoilsfromtopolitosequencesinthebraziliancentralplateau2019.pdf: 8239209 bytes, checksum: 66f402389d8c9eabbc78cf69a0c4fc35 (MD5) Previous issue date: 2019

In many regions across the planet, flood events are now more frequent and intense because of climate change and improper land use, resulting in risks to the population. However, the procedures to accurately determine the areas at risk in regions influenced by inadequate land uses are still inefficient. In rural watersheds, inadequate uses occur when actual uses deviate from land capability, and are termed environmental land use conflicts. To overcome the difficulty to evaluate flood vulnerability under these settings, in this study a method was developed to delineate flood vulnerability areas in a land use conflict landscape: the Batatais municipality, located in the State of S&atilde, o Paulo, Brazil. The method and its implementation resorted to remote sensed data, geographic information systems and geo-processing. Satellite images and their processing provided data for environmental factors such as altitude, land use, slope, and soil class in the study area. The importance of each factor for flood vulnerability was evaluated through the analytical hierarchy process (AHP). According to the results, vast areas of medium to high flood vulnerability are located in agricultural lands affected by environmental land use conflicts. In these areas, amplified flood intensities, soil erosion, crop productivity loss and stream water deterioration are expected. The coverage of Batatais SP municipality by these vulnerable areas is so extensive (60%) that preventive and recovery measures were proposed in the context of a land consolidation&ndash, water management plan aiming flood control and soil and water conservation.

Pouco se conhece sobre a diferenciação pedogenética no Alto Paranaíba (MG), quando são comparados materiais de composição química tão variada, como tufitos, rochas ígneas alcalinas e ultramáficas e carbonatitos, todos de ocorrência na região. Dessa forma, este trabalho teve como objetivo caracterizar física, química e mineralogicamente os solos representativos de três topolitossequências do Alto Paranaíba. Para isso, foram descritos e coletados 11 perfis de solos, entre os municípios de Serra do Salitre, Patrocínio e Coromandel, representando as variações litológicas na faixa do contato geológico entre os grupos Bambuí, rochas vulcânicas ultramáficas e Araxá. Nas amostras de solos foram realizadas análises físicas e químicas de rotina, além de determinações de Fe, Al e Si após extração por ataque sulfúrico; Fe por DCB e oxalato; Fe, Ca, Mg, K, P, Ti e outros metais pesados após digestão total (ataque triácido); e determinação dos diferentes componentes da fração argila por difratometria de raios X. Os Latossolos do Alto Paranaíba são extremamente intemperizados e com índices Ki e Kr muito baixos, indicativos de solos ricos em óxidos de Fe e de Al, não possuindo uma filiação definida com os materiais de origem subjacente, indicando intensa pedoturbação e provável mistura com materiais alóctones. As assinaturas geoquímicas indicativas da natureza ultramáfica são os teores elevados de Cr, Ni, Mn, Fe e Mg. A mineralogia da fração argila dos Latossolos indica a coexistência de vermiculita com hidroxi-Al entrecamadas, caulinita, gibbsita e anatásio, evidenciando uma gênese policíclica dos minerais da fração mais fina e o elevado grau de intemperismo. Nos Cambissolos, a rápida dessilificação atual conduz à coexistência de gibbsita e óxidos de Fe com esmectitas e illitas, em virtude da rápida ação do intemperismo nos substratos de rochas máficas ou ultramáficas-alcalinas, pobres em sílica. Little is known bout the pedogenetic differentiation in Alto Paranaíba, western Minas Gerais, Brazil, when materials with such a variety of chemical compositions as tufite, alkaline-ultramafic igneous rocks and carbonatites are compared, which are all found in this region. The purpose of this study was to characterize the physical, chemical and mineralogical properties of three representative soil topolitosequences of the Alto Paranaíba region. Therefore, 11 soil profiles were described and collected in the Serra do Salitre, Patrocínio and Coromandel counties, representing the influence of mafic-ultramafic bodies along the geological interface between Bambuí and Araxá groups. Soil samples were routinely analyzed for physical and chemical properties, besides determinations of Fe, Al and Si after sulfuric extraction; Fe after extraction by DCB and oxalate; Fe, Ca, Mg, K, P, Ti, and other heavy metals after total digestion (triacid attack); and determination of the different components in the clay fraction by DRX. The Latosols (Oxisols) of the Alto Paranaíba are extremely weathered and have very low Ki and Kr indexes, indicators of soils with high iron and aluminum oxides contents, with no defined relationship with the underlying parent materials, indicating intense pedoturbation and mixture with alloctonous materials. The geochemical signatures of the ultramafic nature are the unusual high content of Cr, Ni, Mn, Fe, and Mg. The clay fraction mineralogy of the Latosols shows the coexistence of VHE, kaolinite, gibbsite, and anatase, indicating a polycyclic genesis of the minerals from the finer fraction and the high weathering degree. In the Cambisols, the current rapid desilification indicates the coexistence of gibbsite and iron oxides with smectites and illite because of the fast weathering in the silicon-poor mafic or alkaline-ultramafic rock substrates.

Os Planossolos assumem, na região do Agreste do Estado de Pernambuco, grande importância econômica, tanto pela sua magnitude de ocupação quanto pela utilização intensiva, especialmente com atividades agropecuárias. Aspectos como dualidade ou retrabalhamento do material de origem e natureza dos processos envolvidos na formação das marcantes diferenciações texturais e nas concentrações de Na e de sais são pontos importantes a serem esclarecidos. Este trabalho teve como objetivo avaliar o processo de pedogênese dos Planossolos no Agreste de Pernambuco, com base nos resultados das análises físicas, químicas, mineralógicas, macromorfológicas e, especialmente, micromorfológicas. Foram estudados três perfis de solos com marcante contraste textural, em trincheiras abertas ao longo de uma topossequência de solos. Realizaram-se análises físicas, químicas, mineralógicas e macro e micromorfológicas. Verificou-se que os solos são autóctones e que os nítidos contrastes texturais, devido à argilização dos horizontes Bt, parecem ser, principalmente, o resultado de uma combinação de processos e não uma simples eluviação-iluviação (lessivagem). Entre esses processos estão incluídos a intemperização de biotitas, com formação in situ de argilas, e as perdas dessa fração, devido a movimentações laterais por arraste mecânico ou dissoluções. A combinação exata desses processos, bem como a acumulação de Na, foi fortemente influenciada pelo posicionamento dos solos no relevo. In the Agreste region of Pernambuco state, Planosols are economically highly important, due to the degree of occupation, as well as the heavy use, mainly for agricultural activities. Aspects such as duality or reworking of parent material, which characterize the processes involved in the formation of the marked textural differences and of Na and salt concentrations, are important points to be clarified. This study aimed to evaluate the pedogenetic process of the Planosols in the region Agreste, state of Pernambuco, based on physical, chemical, mineralogical, macromorphological, and especially micromorphological data. Three soil profiles with marked textural contrast were studied, in trenches opened along a soil toposequence. Physical, chemical, mineralogical, and macro and micromorphological analyses were performed. The soils were found to be autochthonous and the sharp textural contrasts due to argilic Bt horizons seem to be mainly the result of a combination of processes and not simply Elution-illuviation. The processes include the weathering of biotite, forming in situ clay fraction, and losses due to lateral movement by mechanical drag or dissolution. The exact combinations of these processes and Na accumulation were strongly related to the soil position in the landscape.