RESUMO Pequenas variações de relevo influenciam na drenagem e no escoamento superficial, contribuindo para a formação de horizontes superficiais arenosos e subsuperficiais endurecidos (fragipãs e, ou, duripãs) em solos dos Tabuleiros Costeiros. Este trabalho investigou a pedogênese em área de Tabuleiros Costeiros com baixa amplitude altimétrica no Estado da Paraíba; secundariamente, buscamos contribuir para o aprimoramento do Sistema Brasileiro de Classificação de Solos (SiBCS). Quatro perfis de solos foram descritos e coletados para a realização das análises físicas e químicas de rotina, extrações de Fe, Si e Al por digestão sulfúrica, por ditionito-citrato-bicarbonato de sódio, por oxalato ácido de amônio e por pirofosfato de sódio, e as análises mineralógicas das frações areia e argila por difratometria de raios X. A densidade ótica do extrato de oxalato (ODOE) também foi determinada; os resultados obtidos foram estatisticamente avaliados utilizando o programa R. As variações do microrrelevo condicionando fluxos diferenciados de água, juntamente com a textura arenosa dos horizontes superficiais (A e E) e a menor relação areia grossa/areia fina no horizonte subsuperficial, parece favorecer o acúmulo de argila em profundidade nos Espodossolos desenvolvidos no ambiente dos Tabuleiros Costeiros. Para esses solos, o caráter argissólico em nível de subgrupo do SiBCS deveria ser incorporado. Além disso, fases mineralógicas amorfas e, ou, de baixa cristalinidade de Al têm importante participação na formação de horizontes fortemente cimentados (duripãs) dos Espodossolos. Finalmente, a ODOE mostrou-se eficiente como indicador de solos sob processo de podzolização e poderia ser utilizada como critério taxonômico para classificação de Espodossolos pelo SiBCS.

ABSTRACT Small variations of relief may change drainage and runoff and hence promote the formation of sandy surface horizons and hardened subsurface horizons (fragipans and/or duripans) in Coastal Tablelands soils. This study aimed to investigate the pedogenesis on Coastal Tablelands area with low range altimetry in Paraíba state; secondly, we also sought to contribute to the improvement of the Brazilian Soil Classification System (BSCS). Four soil profiles ware described and collected to be submitted to routine physical and chemical analysis, determination of Fe, Al and Si extracted by sulfuric acid digestion, sodium citrate-bicarbonate-dithionite and acid ammonium oxalate, sodium pyrophosphate, and mineralogical analysis in the sand and clay fractions by X-ray diffractometry. Optical density of the oxalate extract (ODOE) was also determined; the results were statistically evaluated using the R software. Microrelief variations conditioning differentiated water flows, along with the sandy texture of the surface horizons (A and E) and the lower coarse sand/fine sand ratio in the subsurface horizon, seem to promote clay accumulation in depth in the Spodosols developed on Coastal Tablelands environments. For this soils, the argilluvic (argissólico) character at the subgroup level of the BSCS should be incorporated. In addition, Al amorphous mineral phases and/or poorly crystalline play an important role in the formation of strongly cemented horizons (duripans) of the Spodosols, as also reported by other authors. Finally, the ODOE showed to be an efficient indicator of soils under podzolization process, being possible its use as a taxonomic criterion for classification of Spodosols by the BSCS.

ABSTRACT Sequences of thick and eroded soils in hills surfaces are cultivated with banana since the beginning of the last century in the Northeast of Pernambuco (PE), Brazil. Measurements of soil properties depending on soil slope under intensive agricultural cultivation are limited mostly as the pedogenetic approach. This study aimed to identify the dominant soil types, to evaluate morphological, physical, chemical, and mineralogical properties of soil profiles, and link them to the relief position under continuous banana cropping, in the transition Mata-Agreste of PE. Three slope classes and soil profiles were considered: Profile 1 (P1), upper third of the elevation slope; Profile 2 (P2), middle third of the slope; and Profile 3 (P3) lower third. They were opened, described, and soil samples collected from all horizons at a typical slope of the region. Independent of relief position and land use, all soils are deep (>1.50 m) and present the argic horizons (Bt) developed in all steeply sloping surfaces (15-33 %). The Bt horizon presented the highest values of soil bulk density and microporosity. Despite the presence of illite, all the soil profiles showed remarkable degree weathering, are mostly kaolinitic, besides presenting goethite and quartz in the soil clay fraction, and predominance of quartz in the silt and sand fraction. Water-stable aggregates >2 mm were dominant in all the relief positions. Acidity, low cation exchange capacity, and in general, nutrient poverty were observed in the soil profiles, as opposed accumulation of exchangeable cations on the lower third of the slope (P3). However, the soil properties were affected by land use and water erosion. The Ap horizons showed the highest values of pH, exchangeable bases, phosphorus available, and organic carbon due to agricultural practices, while the steepest slope (P2) had the lowest content of clay, phosphorus and mean weight diameter of aggregates, and higher organic carbon content, in the superficial horizon, due to removal and deposition by water erosion. From the upper third to the lower third of the slope, Nitic Acrisol, Haplic Acrisol, and Nitic Lixisol were formed.

ABSTRACT On the southern coast of Pernambuco State (PE), Brazil, lithotypes of the Cabo Basin (volcanic and sedimentary rocks), in association with the relief, allow the determination of the dynamics of the formation of Nitossolos Háplicos (Nitisols), including those with high levels of exchangeable aluminum. The objective of this study was to evaluate the influence of lithological diversity (basalt and sedimentary siliciclastic rocks) on the morphological, physical, chemical, and mineralogical properties of Nitossolos Háplicos along a slope (P1-summit, P2-backslope, P3-footslope) on the southern coast of PE, in order to consider its genesis and the relation of soil properties to adjacent environments and to evaluate its framing within the Brazilian Soil Classification System (SiBCS). The interaction of lithology/soil permeability and climate indicate significant differences in the mineralogical composition and dynamics of soil chemical elements. The profiles P1 and P2 are subject to monosialitization, ferralitization, and alitization processes. All profiles showed high Fe contents (ferric soils) and clay fractions, consisting primarily of kaolinite, goethite, hematite, and gibbsite, as well as quartz and feldspar in the sand and silt fractions. However, smectite minerals (P3) are probably inherited from the sedimentary source material. In the conglomerate samples, under P3, biotite, muscovite, and plagioclase were identified. Allytic characteristics (P3) are probably associated with the weathering of aluminous smectite minerals. These properties distinguish these soils from adjacent Nitossolos and other Nitossolos in Brazil. For the classification of soils according to SiBCS, considering the high levels of Fe and Al, Nitossolo Háplico distroférrico (P1 and P2) and Nitossolo Háplico alitiférrico (P3) are suggested, and according to the World Reference Base of Soils (WRB), the soils are classified as Ferritic Nitisols.

ABSTRACT Weathering and pedogenesis have been studied for a wide range of rocks and climates around the world. However, the eruption of rhyolitic magmas is a rare geological event, which leads to few studies associated with the rhyolite-soil-landscape relationship. In this context, this study evaluated the influence of rhyolite weathering on the properties of soils along a slope in an Atlantic Forest environment in the state of Pernambuco, northeastern Brazil. Four weathering profiles derived from rhyolites were classified and sampled for chemical, physical, mineralogical, micromorphological, differential thermal, and thermogravimetric analyses. The chemical properties reflect the original rock rich in felsic minerals, poor in bases, and the types of clay minerals. The clay fraction of the profiles consists mainly of 1:1 phyllosilicates and oxides, indicating intermediate weathering. However, variations in the degree of structure weathering were evidenced by the presence of partially preserved fragments of the original rock in the sand fraction of the soils. The tropical humid climate of the region influenced conversion of hematite to goethite through the xanthization process, and the subsurface drainage deficiency allowed the formation of halloysite in the lowest position of the landscape. Because it is an acid rock with an aphanitic texture and porphyritic relative size of crystals, rhyolite weathering resulted in the formation of dystrophic soils, with predominance of quartz in the silt fraction. From the top to the lower third of the slope, a Haplic Cambisol, an Abruptic Lixisol, and two Haplic Lixisols were formed.

ABSTRACT The semiarid region of northeastern Brazil has a large area occupied by Planosols, where in the State of Pernambuco these soils are mainly used for livestock farming and subsistence crops. The knowledge on these soils is limited, which compromises the understanding on their behavior, potentialities and limitations.This study aimed to analyze morphological, chemical, physical and mineralogical attributes of Planosols developed under different geoenvironmental conditions. Morphological descriptions and chemical, physical and mineralogical analyses were performed in four profiles of Planosols along a rainfall gradient. An increase in rainfall allowed for an increase in the clay content in the Bt horizon and a reduction in ESP, EC, Na+, CEC, S, pH (water and KCl) and soil density. Horizons A and E were thicker in Planosols in more humid environments. The increase in ESP associated with the presence of expansive minerals (smectite and vermiculite) allowed the development of a prismatic structure in Haplic Planosols and a columnar structure in Natric Planosols. The mineralogical assembly is indicative of poorly weathered soils. The mineralogical assemblies of the silt and clay fractions were similar in the different geoenvironments, while higher contents of easily alterable minerals were observed in the composition of the sand fraction in environments with a drier climate.

Estudos etnopedológicos têm sidos direcionados principalmente ao uso do solo para fins agrícolas e práticas associadas. Entretanto, populações camponesas e indígenas utilizam os recursos do solo para outras finalidades, incluindo a confecção de cerâmica artesanal. Neste estudo, foi descrito e analisado o conhecimento tradicional relacionado ao uso de solos para confecção não industrial de cerâmica por agricultores ceramistas, no município de Altinho, Estado de Pernambuco, localizado na região semiárida brasileira. Técnicas etnocientíficas foram utilizadas para registrar o conhecimento local, com ênfase na descrição dos materiais de solo reconhecido pelos ceramistas, nos atributos utilizados por eles para identificar os materiais de solo e nos critérios empregados por esses para diferenciar e relacionar esses materiais. Os informantes reconheceram três categoriais de materiais de solo: “terra”, “barro” e “piçarro”. O arranjo em múltiplas camadas desses materiais no perfil de solo foi similar ao arranjo dos horizontes descritos por pedólogos. O “Barro vermelho” foi considerado pelos ceramistas como o principal recurso cerâmico. Os ceramistas utilizaram critérios morfológicos e utilitários para distinguir os diferentes materiais de solo. Os solos de todos os locais estudados eram Planossolos influenciados por sais. De acordo com o Sistema Brasileiro de Classificação de Solos, esses solos foram classificados como Planossolo Háplico e Planossolo Nátrico.

Ethnopedological studies have mainly focused on agricultural land uses and associated practices. Nevertheless, peasant and indigenous populations use soil and land resources for a number of additional purposes, including pottery. In the present study, we describe and analyze folk knowledge related to the use of soils in non-industrial pottery making by peasant potters, in the municipality of Altinho, Pernambuco State, semiarid region at Brazil. Ethnoscientific techniques were used to record local knowledge, with an emphasis on describing the soil materials recognized by the potters, the properties they used to identify those soil materials, and the criteria employed by them to differentiate and relate such materials. The potters recognized three categories of soil materials: “terra” (earth), “barro” (clay) and, “piçarro” (soft rock). The multi-layered arrangement of these materials within the soil profiles was similar to the arrangement of the soil horizon described by formal pedologists. “Barro vermelho” (red clay) was considered by potters as the principal ceramic resource. The potters followed morphological and utilitarian criteria in distinguishing the different soil materials. Soils from all of these sites were sodium-affected Alfisols and correspond to Typic Albaqualf and Typic Natraqualf in the Soil Taxonomy (Soil Survey Staff, 2010).

O Cerrado vem sendo alvo de exploração sem a devida preocupação com a manutenção dos recursos naturais, e os sistemas de produção têm se caracterizado pelo uso intensivo do solo. O objetivo desta pesquisa foi avaliar o efeito do plantio direto na alteração das características físicas de Latossolos Amarelos cultivados com soja. A pesquisa foi realizada na Serra do Quilombo, localizada no cerrado piauiense. Foram verificadas as alterações nos atributos do solo em decorrência da utilização agrícola, que foi iniciada com plantio convencional (PC), posteriormente substituído pelo sistema de plantio direto (PD). Foram amostrados solos com diferentes históricos de uso: PC7/PD8: sete anos de plantio convencional e oito de plantio direto; PC5/PD4: cinco anos de plantio convencional e quatro de plantio direto; PC3/PD3: três anos de plantio convencional e três de plantio direto; e CN: solo com cerrado nativo. As propriedades avaliadas foram: distribuição das frações granulométricas, argila dispersa em água, grau de floculação, relação silte/argila, densidade do solo e das partículas, porosidade total, macro e microporosidade. Os resultados foram submetidos à análise de variância e, como análise complementar, utilizaram-se técnicas multivariadas. Para identificação das características físicas semelhantes do solo, utilizou-se a técnica de análise multivariada denominada análise fatorial. Maiores valores de densidade do solo e de microporosidade foram observados nos sistemas PD, e de macroporosidade e porosidade total, no CN. Os resultados mostraram que a implementação do sistema plantio direto alterou o volume total de poros e a macroporosidade, porém estes apresentaram valores dentro da faixa considerada não restritiva. A análise fatorial possibilitou a visualização conjunta dos atributos do solo, sendo as propriedades densidade do solo, porosidade total e macroporosidade as que mais sofreram variação nos sistemas de uso.

The Cerrado is being increasingly exploited in production systems characterized by intensive land use, without due concern for the preservation of natural resources. The objective of this research was to evaluate the effect of no-tillage soybean on the physical properties of Oxisols. The study was carried out in the region of "Serra do Quilombo", located in the Cerrado region of the State of Piauí. To assess changes in soil properties caused by agricultural use, soil samples were collected from conventional (CT) and no tillage (NT) areas with different use history; PC7/PD8 - seven years CT followed by eight years NT; PC5/PD4 - five years CT followed by four years NT; PC3/PD3 - three years CT and three years NT; and NC - native cerrado vegetation. The results were subjected to variance analysis and multivariate techniques. Factorial analysis, a Multivariate Analysis technique, was used to identify similarities within soil physical properties. The evaluated soil properties were particle-size-distribution, water dispersible clay, clay flocculation degree, silt / clay ratio, bulk and particle density, total porosity, macro and microporosity. Greater bulk density and microporosity values were observed in NT and macroporosity and total porosity were higher under NC. The results showed that NT changed the total pore volume and macroporosity, however the values were not considered restrictive. The Factorial analysis enabled the combined visualization of soil properties, indicating that the soil properties bulk density, total porosity and macroporosity were most affected by the use systems.

O objetivo deste trabalho foi estudar as relações solo-relevo em uma topossequência de transição campo/floresta na região de Humaitá, AM. A área do estudo foi selecionada com base na representatividade regional e no grau de preservação do ambiente. O estudo foi realizado ao longo de um caminhamento que atravessou os diferentes pedoambientes, partindo do ambiente de campo natural até o ambiente de floresta. Esses pedoambientes foram identificados e delimitados conforme a curvatura do terreno, expressão dos padrões vegetacionais e características pedológicas. Foram abertas trincheiras nos diversos segmentos e os perfis foram caracterizados morfologicamente e coletados por horizonte. Foram realizadas análises físicas e químicas para caracterização e determinados SiO2, Al2O3 e Fe2O3 por ataque sulfúrico, óxidos de Fe "livres" com ditionito-citrato-bicarbonato e o ferro mal cristalizado com oxalato de amônio. Análises mineralógicas foram realizadas por difratometria de raios X. Os resultados sugerem que a variação dos solos na topossequência tem relação direta com a variação do relevo, que condiciona a drenagem e o nível do lençol freático.

The objective of this work was to study soil-relief relations in a grassland-forest transition, in the region of Humaitá, Amazonas State, Brazil. The study area was selected based on the criterion of regional representativity (most common landscape) and in the level of environmental preservation. The sample collection was carried out in a transect from the grassland towards the forest, and the different soil environments were identified and limited according relief position, vegetation patterns and soil characteristics. Soil profiles were morphologically characterized and samples collected from all horizons for physical and chemical analysis for normal profile characterization. including SiO2, Al2O3 and Fe2O3 extracted by H2SO4 attack, free iron oxides by DCB extraction and poor crystalline iron oxides extracted by ammonium oxalate. Mineralogical analysis was also carried out by X-ray diffraction. The results suggest that soil variation in the landscape was directly related with the relief, which determines soil drainage and water table level.

O conceito de superfície geomórfica permite uma interligação entre os diferentes ramos da ciência do solo, tais como geologia, geomorfologia e pedologia. O objetivo deste trabalho foi estudar as relações solo-superfície geomórfica em uma topossequência de 4.500 m na transição várzea/terra firme, na região de Humaitá (AM). Do divisor de águas até a planície do rio Madeira, as superfícies geomórficas foram identificadas com base na ruptura do declive do terreno, em critérios estratigráficos e em outras observações de campo. Foram abertas trincheiras nos segmentos mapeados da topossequência, os perfis de solos foram caracterizados morfologicamente e amostras foram coletadas de seus horizontes. Foram realizadas análises físicas de granulometria, argila dispersa em água, grau de floculação, densidade do solo, densidade das partículas, porosidade total e condutividade hidráulica do solo saturado. As análises químicas incluíram pH em água e KCl; Ca, Mg, K, Na e Al trocáveis; P disponível; H + Al e C orgânico; SiO2, Al2O3 e Fe2O3 do ataque sulfúrico; Fe "livre" extraído com ditionito-citrato-bicarbonato; e ferro mal cristalizado, extraído com oxalato de amônio. Os índices ∆pH, relação silte/argila, Ki e Fe d/Fe t indicaram solos mais intemperizados na parte mais elevada da paisagem em comparação ao declive de infiltração, declive convexo e sopé aluvial, coincidindo com a maior idade da superfície geomórfica I em relação às superfícies geomórficas II e III. As variações dos solos na transeção estudada mostraram solos mais intemperizados nos ambientes de terra firme quando comparados aos solos dos ambientes de várzeas. O entendimento dos eventos geomórficos favoreceu a compreensão da variação dos atributos dos solos na topossequência.

The geomorphic surface concept allows interrelationship among various branches of soil sciences, such as geology, geomorphology and pedology. The purpose of this study was to investigate soil-geomorphic surface relations along an upland-downland toposequence in the region of Humaitá, Amazonas State, Brazil. A transect of 4,500 m was studied from the water divide downstream to the flood plain of the Madeira river. The geomorphic surfaces were identified based on the slope rupture, stratigraphic criteria and on other field observations. Trenches were dug in the identified slope segments, the soils were morphologically characterized and samples collected from each horizon. The physical properties particle size distribution, water dispersible clay and flocculation degree, soil and particle density, total porosity, and saturated hydraulic conductivity were determined. Chemical analysis involved pH in water and KCl; exchangeable Ca, Mg, K, Na, and Al; available P, Al + H and organic C; total SiO2, Al2O3 and Fe2O3 by sulfuric acid digestion; free iron oxides extracted with dithionite-citrate-bicarbonate and poor crystalline iron oxides with ammonium acid oxalate. The values of ∆pH, silt/clay, Ki and Fe d/Fe t ratio indicated more weathered soils at the top of the landscape, than along the infiltration slope, convex slope and alluvial footslope, coinciding with the older age of the soils of the geomorphic surface I than of II and III. The soil variations in the studied transect were related to the surface age, parent material and slope gradient. The understanding of the geomorphic events was important to explain the variation of soil properties in the toposequence.

Considerando as dimensões da região amazônica e a necessidade de estudos que estabeleçam conexões entre os solos e a expressão da paisagem, o objetivo deste trabalho foi estudar as relações solo-paisagem em uma topossequência sobre substrato granítico em Santo Antônio do Matupi, Manicoré, AM. Foi estabelecido um caminhamento de 3.000 m a partir do "espigão" da vertente, no seu sentido mais suave, com identificação dos segmentos da vertente com base na "quebra" do declive do terreno. Foram abertas trincheiras nos segmentos de vertente mapeados, e perfis foram caracterizados morfologicamente, coletando-se amostras de seus horizontes. Foram realizadas análises físicas (textura, ADA e GF, Ds e Dp, Pt e CHSS), químicas (pH em água e KCl, Ca, Mg, K, Na e Al trocáveis, P disponível, H + Al e C orgânico; SiO2, Al2O3 e Fe2O3 (método do H2SO4) e óxidos de Fe "livres" extraído com ditionito-citrato-bicarbonato e o Fe mal cristalizado extraído com oxalato de amônio) e mineralógicas (frações areia, silte e argila), usando difratometria de raios X. As variações do relevo favoreceram a presença de solos distróficos nos topos e solos eutróficos no sopé de transporte. As variáveis ΔpH, relação silte/argila, V % e relação Fed/Fet indicaram a presença de solos mais intemperizados nas áreas de topo da paisagem e solos com menor grau de evolução na encosta e no sopé de transporte. A composição mineralógica da fração argila mostrou-se relativamente homogênea, com predominância de caulinita e gibbsita e menor proporção de mica e quartzo.

In view of the size of the Amazon region and the need to establish connections between landscape and soil characteristics, the aim of this study was to investigate soil-landscape relationships in a toposequence on granite substrate in Santo. Antônio Matupi, Manicoré, AM. The study was carried out along a transect of 3,000 m from the top downwards, where different slope segments were identified. Profile pits were opened in each slope segment, the soils were morphologically characterized and samples collected from the horizons for physical, chemical and mineralogical analysis. For the physical analysis, particle size distribution, water dispersible clay and flocculation degree, soil and particle density, total porosity, and hydraulic conductivity were measured. Chemical analysis involved pH in water and KCl; Ca, Mg, K, exchangeable Na and Al, available P, Al + H and organic C; SiO2, Al2O3 and Fe2O3 (H2SO4 method); free iron oxides extracted with dithionite-citrate-bicarbonate and poor crystalline iron oxides extracted with ammonium acid oxalate). The mineralogy of the sand, silt and clay fractions was determined by X ray diffraction. The changes in the relief favored the occurrence of dystrophic soils on the summit and eutrophic soils at the foot. The variables ??"pH, silt/clay ratio, base saturation and Fed/Fet ratio indicated that the most weathered soils were related with the top positions of the landscape, while soils with lower development degree were related to slope and foothill positions. The clay fraction mineralogy with prevailing kaolinite and gibbsite and small amounts of mica and quartz was relatively uniform in the transect.

Apesar da existência de muitas pesquisas sobre as Terras Pretas Arqueológicas, poucos são os trabalhos que têm procurado entender e esclarecer dúvidas sobre a gênese e o comportamento destes solos. Dessa maneira, o objetivo deste trabalho foi caracterizar e classificar terras pretas arqueológicas de quatro sítios na Região do Médio Rio Madeira. Nesses locais, foram abertas trincheiras e os perfis caracterizados morfologicamente e amostrados. Foram realizadas as seguintes análises físicas: textura, argila dispersa em água, densidades do solo e das partículas, porosidade total e condutividade hidráulica saturada. As análises químicas constaram de: pH em água e KCl, cátions trocáveis, Al trocável, P disponível, acidez titulável (H+Al) e C orgânico, Al2O3 e Fe2O3 e SiO2 extraídos pelo método do ataque sulfúrico, e teor de C das substâncias húmicas. Para determinar óxidos de Fe foram utilizados o ditionito-citrato-bicarbonato (Fed) e o oxalato ácido de amônio (Feo). As análises mineralógicas das frações areia, silte e argila foram feitas por difratometria de raios-X. Os perfis foram classificados no Sistema Brasileiro de Classificação de Solos como: Argissolo Vermelho Amarelo, Argissolo Acinzentado e Argissolo Amarelo. Os solos apresentaram horizonte A antrópico com características químicas e de profundidade semelhantes, sugerindo certa similaridade dos fatores antrópicos que promoveram sua formação. Os horizontes antrópicos de todos os perfis amostrados na região tinham caráter eutrófico e teores altos a muito altos de fósforo disponível, sempre maiores que os dos horizontes subjacentes. Sugere-se a inclusão do subgrupo antrópico no SiBCS.

Although several studies have been published about the Archaeological Dark Earths, few of them tried to understand and elucidate questions about the pedogenesis and behavior of these soils. Thus, the objective of this study was to characterize and classify Archaeological Dark Earths in four sites, selected in the region of the Middle Madeira River. Four pedons were morphologically characterized and collected for chemical, physical and mineralogical analysis. Physical analysis involved particle size distribution, water dispersible clay, soil bulk and particle density, total porosity and saturated hydraulic conductivity. Chemical analysis involved pH in water and KCl, exchangeable cations, exchangeable aluminum, available P, extractable acidity (Al+H), organic carbon and, SiO2, Al2O3 and Fe2O(3)3 extracted with H2SO4. Free iron oxides were extracted with dithionite-citrate-bicarbonate and poor crystalline iron oxides were extracted using ammonium acid oxalate. Mineralogical analysis of sand, silt and clay fractions were carried out by X-ray diffraction. The studied soils were classified in the Brazilian System of Soil Classification as Red Yellow Argisol, Gray Argisol and Yellow Argisol. The presence of the anthropogenic A horizons with similar chemical properties and depths in all studied sites suggests that similar conditions have influenced their formation. All anthropogenic horizons studied in the region showed high base saturation and high to very high P availability as compared to subjacent horizons. The inclusion of the anthropogenic subgroup in the Brazilian System of Soil Classification was also suggested.

As condições pedoambientais promovem alterações nos atributos do solo. Sendo assim, o objetivo deste trabalho foi estudar as interferências dos pedoambientes nos atributos do solo de uma topossequência de transição Campos/Floresta na região de Humaitá, AM. Escolheu-se uma topossequência característica de sequência Campos/Floresta, em seguida foi estabelecido um caminhamento, partindo do ambiente de campo natural até o ambiente de floresta. Esses pedoambientes foram identificados e delimitados conforme a expressão dos padrões vegetacionais. Foram coletadas 20 amostras laterais ao caminhamento, representativas de cada uma das unidades pedoambientais da topossequência (campo alto: 0,0-14 e 0,30-0,66 m; campo baixo: 0,0-0,15 e 0,27-0,80 m; zona de ecótono: 0,0-0,15 e 0,32-0,50 m; floresta: 0,0-0,15 e 0,67-100 m), totalizando 80 amostras. O critério de escolha das profundidades foi a coincidência com os horizontes diagnósticos superficiais e subsuperficiais determinados na descrição morfológica dos perfis. Foram realizadas análises físicas de textura, argila dispersa e grau de floculação, densidades do solo e das partículas, porosidade total e condutividade hidráulica. Nas análises químicas foram determinados pH em água e KCl, Ca, Mg, K, Na e Al trocáveis, P disponível, H+Al e C orgânico. Os atributos físicos e químicos do solo apresentaram-se dependentes dos pedoambientes. Com o uso das técnicas estatísticas multivariadas foi possível distinguir três diferentes ambientes que equivalem a três pedoambientes.

The pedoenvironmental conditions promote changes in soil properties, so the aim of this work was to study Interference of the pedoenvironment on soil properties in a topossequence of the Grassland/Forest transition in the Humaitá region, AM. Was picked up a topossequence characteristic sequence Grassland/Forest, then a pathway was established, from a field environment to the natural forest environment. These pedoambients were identified and defined as the expression patterns of vegetation. Were collected 20 samples at the representative side of the profiles in each one of the pedoambiental units of the topossequence (top grassland: 0.0-14 and 0.30-0.66 m;low grassland : 0.0-0.15 and 0.27-0.80 m; ecotone zone: 0.0-0.15 and 0.32-0.50 m; forest: 0.0-0.15 m 0.67-100 as a total of 80 samples) being the criteria for sampling depths the coincidence with the surface and subsurface diagnostic horizons determined by the morphological description of the profiles. Were performed physical analysis of texture, clay dispersion and flocculation, soil bulk density and particle porosity and hydraulic conductivity. In the chemical analysis were determined pH in water and KCl, Ca, Mg, K, Na and Al contents, available P, H + Al and organic carbon. The physical and chemical soil were dependent on the pedoambients. With the use of multivariate statistical techniques was possible to distinguish three different environments that are equivalent to three pedoambients.

As variações dos atributos do solo ocorrem em função de vários fatores tais como: clima, material de origem, vegetação e, especialmente do relevo, que regula o escoamento superficial e a drenagem, e tem influência no tempo de exposição dos materiais à ação do intemperismo. O objetivo deste trabalho foi estudar a influência dos diferentes segmentos de vertente nos atributos do solo em uma toposseqüência na região de Manicoré, AM. Foi estabelecido um caminhamento de 3.000 m a partir do "espigão" da vertente no sentido do caimento mais suave do relevo e os segmentos da vertente foram determinados com base na "quebra" de declive do terreno. Foram coletadas 20 amostras nos diferentes segmentos de vertentes identificados: topo alto: 0,0-0,19 e 0,37-0,60 m; meia encosta: 0,0-0,28 e 0,60-0,80 m; sopé de transporte: 0,0-0,15 e 0,42-0,71 m e topo baixo: 0,0-0,15 e 0,20-0,40 m. O critério de escolha das profundidades foi à coincidência com os horizontes diagnósticos superficiais e subsuperficiais determinados na descrição morfológica dos perfis. Foram realizadas análises físicas de textura, densidades do solo e das partículas, porosidade total e condutividade hidráulica, Nas análises químicas foram determinados pH, em água e em KCl, Ca, Mg, K, e Al trocáveis, P disponível, H+Al e C orgânico. Com o uso das técnicas estatísticas multivariadas foi possível distinguir diferentes ambientes geomórficos independentes dos segmentos de vertente identificados. As variações do relevo favoreceram a presença de solos distróficos no topo alto e solos eutróficos no sopé de transporte.

Variations of soil properties are consequence of several factors such as: climate, parent material, vegetation and, particularly relief, which controls runoff and drainage, and has influence in the exposure of parent materials to the weathering action. The objective of this work was to study the influence of the slope segments on soil attributes of a topossenquence in the Manicoré region, AM. Twenty samples were collected in each of the several slope segments identified along a 3 km transect, from the top and toward the lower part of the topography. The slope segments and the sampling depths were: high top (0.0-0.19 and 0.37-0.60 m), medium slope (0.0-0.28 and 0.60-0.80 m); lower slope (0.0-0.15 and 0.42-0.71 m) and low top (0.0-0.15 and 0.20-0.40 m). The sampling depths were coincident with the surface and subsurface diagnostic horizons defined in the profile morphological description. Physical analysis involved particle size distribution, soil and particle density, total porosity and saturated hydraulic conductivity. In the chemical analysis pH in water and KCl, exchangeable cations, exchangeable Al, available P, H+Al, organic carbon were determined. The use of multivariate statistic techniques enabled the distinction of different soil geomorphic environments independent of the slope segments identifications. The relief variations contributed to the presence of dystrophic soils in the high top and eutrophic soils in the lower slope.

Os brejos de altitude nordestinos constituem uma disjunção da mata atlântica, formando ilhas de floresta úmida em plena região semiárida, tendo uma condição climática bastante atípica, favorecida pela ocorrência de chuvas orográficas, com precipitação pluvial que pode atingir valores superiores a 1.200 mm por ano. No Estado de Pernambuco, a maioria dos estudos em brejos de altitude abrange os aspectos botânicos e faunísticos, sendo, portanto, importante a realização de estudos para caracterização dos recursos edáficos. Com intuito de estudar os solos de brejos de altitude no Sertão Pernambucano e avaliar a influência dos diversos fatores pedogenéticos na sua formação e evolução, foi feita a caracterização morfológica, física, química e mineralógica de três perfis no maciço de Triunfo, em diferentes altitudes, localizados nos municípios de Serra Talhada (P1), Santa Cruz da Baixa Verde (P2) e Triunfo (P3), formando uma topoclimossequência. Os perfis estudados apresentam características morfológicas similares, relacionadas com o pequeno grau de desenvolvimento pedogenético, principalmente nos perfis P3 (Triunfo) e P2 (Santa Cruz), classificados, respectivamente, como Cambissolo Háplico Tb Eutrófico latossólico e Cambissolo Háplico Tb Eutrófico típico. O perfil P1 (Serra Talhada), localizado no sopé, apresentou menor teor de argila e acentuado gradiente textural, resultante de descontinuidade litológica, sendo classificado como Argissolo Vermelho-Amarelo distrófico abrúptico (cambissólico). Todos os solos deste estudo são oriundos de rochas sieníticas, sendo, pelo menos em parte, influenciados pelo transporte e pela deposição de materiais oriundos da parte superior do relevo. O perfil de Triunfo, em local mais úmido, apresentou o maior grau de desenvolvimento em relação aos demais. O clima, atuando principalmente pela variação de umidade, não foi, entretanto, o único fator de formação responsável pela diferenciação dos solos ao longo da topoclimossequência, devendo-se ressaltar, também, a influência do material de origem e do relevo.

Highland forests in mountains of Northeast Brazil are islands of humid Atlantic forest in the midst of the semi-arid region. The climatic conditions are rather atypical, improved by the occurrence of orographic rainfall, which can reach 1,200 mm per year. In the state of Pernambuco, most of the scientific studies in these humid highland forests are focused on botanical and zoological aspects only, with very little information about soils. Aiming to study the soils of the humid mountains in the semi-arid region and to evaluate the influence of the various soil-forming factors on formation and evolution, three soil profiles were characterized for morphological, physical, chemical, and mineralogical properties in the Triunfo mountain range, at different altitude levels. The soil profiles were located in the municipalities of Serra Talhada (P1), Santa Cruz da Baixa Verde (P2) and Triunfo (P3), along a moisture and altitude gradient (topo-climatic sequence). The soils were morphologically similar, due to the low development degree, mainly in the soil profiles P3 (Triunfo) and P2 (Santa Cruz), classified, respectively, as Oxic Haplustept and Typic Haplustept. In the lower part of profile P1 (Serra Tallhada), a low clay content and greater textural gradient classified the soil as Typic Haplustult. The results showed that all studied soils were developed from syenitic rocks, with influence of sediments from the upper part of the relief. The development degree of the soil of Triunfo, with the highest rainfall levels, was higher than of the others. Climate, acting mainly by the variation in moisture, was however not the only soil forming factor responsible for soil differentiation along the sequence, but parent material and relief were important as well.