Brazilian Soil Classification System Research Articles

PEDOGENESIS ON COASTAL TABLELANDS AREA WITH LOW RANGE ALTIMETRY IN PARAÍBA STATE

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.

Field Description and Identification of Diagnostic Qualifiers for Urban Soils in Brazil

Human activities often alter soils found in urban areas. These alterations affect their environmental functions and potential for use. However, soils from urban areas in Brazil have not been surveyed and identified, which can pose a technical problem for the development of the city. Considering the importance of urban environments and their soils, this study aimed to evaluate the environmental and morphological characteristics and the physical properties of urban soils in Santa Maria, Rio Grande do Sul, Brazil. The purpose was then to organize a protocol for describing urban soils and to identify diagnostic qualifiers to subsidize establishment of an order that allows proper classification of these soils in the Brazilian Soil Classification System. The protocol containing general and environmental notes and morphological notes and qualifiers was organized based on the experience of this study and the relevant literature. The environmental, morphological, and physical analyses carried out supported interpretation of the urban soils of Santa Maria, their classification in the World Reference Base for Soil Resources system, and identification of diagnostic qualifiers proposed for the Brazilian Soil Classification System. The protocol tested in this study was adequate for data collection in the field. Soils had high variation in layer thickness, particle size composition, color, bulk density, saturated hydraulic conductivity, penetration resistance, stoniness, and the presence of artifacts. Considering the establishment of a Brazilian taxonomy for urban soils, the field data led to the proposal for new qualifiers, such as Saprolitic (residual saprolite material), Impervic (sealed/impermeable layer), Multigranic (layers with contrasting textures), Stonic (layers with stoniness), and Saprorockic (layers constituted of transported saprolite), which can be used as diagnostic attributes in the Brazilian Soil Classification System and even contribute to improvement of the order of Technosols in the World Reference Base For Soil Resources system.

GENESIS AND CHARACTERISTICS OF SOILS OF THE SANTANAMOUNTAIN RANGE IN THE SERIDÓ REGION, RIO GRANDE DO NORTE, BRAZIL

ABSTRACT Rio Grande do Norte has mountain formations with edaphoclimatic conditions different from those predominating in the state, presenting deeper,acid soils, and milder climate. Among these formations, is the Santana mountain range, which is part of the Serra do Martins Formation. The objective of this work was to interpret the pedogenesis of the representative soils of the Santana mountain range through morphological, physical, and chemical characterizations of soil profiles and evaluate the effect of these attributes on the distribution of pedological forms along the landscape using multivariate analysis. Morphological, physical, and chemical analyses of seven soil profiles of the Santana mountain range were performed. The soils were classified according to the Brazilian Soil Classification System and the data subjected to multivariate analysis. The representative soil classes found were: LATOSSOLO AMARELO Distrófico argissólico; LATOSSOLO AMARELO Eutrófico argissólico; NEOSSOLO QUARTZARÊNICO Órtico típico; NEOSSOLO LITÓLICO Eutrófico fragmentário; NEOSSOLO REGOLÍTICO Eutrófico típico and CAMBISSOLO HÁPLICO Tb Eutrófico léptico. According to the analysis of the morphological attributes, the parent material had great influence on the formation of the different soil classes found in the Santana mountain range. The soil textural classes varied from sand to sandy clay loam. According to the analysis of the chemical attributes, the soil profiles presented acid reaction, great variation of base saturation, and low electrical conductivity. The multivariate analysis established groups of representative soil profiles of the Santana mountain range through the distinction of their physical and chemical attributes, mainly of subsurface diagnostic horizons.

Spodosols in Brazil: distribution, characteristics and diagnostic attributes of spodic horizons

Spodosols are reported in specific environments of Brazil, such as sandy materials in the Amazon and Pantanal basin, sandbanks in the coastal fringes and coastal tableland areas, and a few in high-altitude mountains with quartz-rich rocky substrates. This study describes variations in characteristics and attributes of spodic horizons from soils classified as Spodosols in Brazilian pedoenvironments. Data were obtained from the literature, comprising landscape and location, morphological characteristics, physical and chemical attributes of Spodosol profiles, classified by the Brazilian Soil Classification System (SiBCS). The data grouped according to the pedoenvironments demonstrated the predominance of the sand fraction in the spodic horizons. The finer texture influences the organic carbon and sum of bases accumulation. Soils from the Pantanal basin with high pH values and low organic carbon content differ from the central concept of Spodosols and the podzolisation process. The aluminium and iron extractable by selective dissolution indicate higher participation of aluminium in detriment to iron. The establishment of quantitative values in the SiBCS for attributes associated with the podzolisation process is important to correlate with international soil taxonomic systems and global databases.

Clay Mineralogy of Brazilian Oxisols with Shrinkage Properties

ABSTRACT Shrinkage capacity (carater retratil in Portuguese) is a new diagnostic characteristic recently introduced in the Brazilian System of Soil Classification (SiBCS) to indicate shrink and swell properties observed in subtropical soils from highland plateaus in southern Brazil, specifically in Oxisols with brown colors. In soils located in road cuts exposed to drying for some weeks, strong shrinkage of soil volume is observed in these soils, resulting in the formation of pronounced vertical cracks and large and very large prismatic [...]

Ethnopedology of a Quilombola Community in Minas Gerais: Soils, Landscape, and Land Evaluation

Quilombolas are Afro-brazilian rural peasants who descended from escaped slaves who tried to carve out territories of autonomy (called Quilombos) by collective organization and resistance. Despite many anthropological and ethnopedological studies, little research has been carried out to identify the agricultural practices and the knowledge of people who live in the Quilombos (Quilombolas). Peasant communities who live from land resources have wide empirical knowledge related to local soils and landscapes. In this respect, ethnopedology focuses on their relationship with local practices, needs, and values. We carried out an ethnopedological evaluation of the soils, landscape and land suitability of the Malhada Grande Quilombola Territory, aiming to examine the local criteria involved in land-use decision making, and evaluate the legitimacy of local knowledge. For this purpose, participatory workshops allowed environmental stratification of the Quilombolas into landscape units, recognition of soil types, and evaluation of land-use criteria. This approach was combined with conventional soil sampling, description, and analysis. The Brazilian System of Soil Classification and its approximations to the WRB/FAO system and the SAAT land evaluation system were compared with the local classificatory systems, showing several convergences. The Quilombolas stratified the local environment into eight landscape units (based on soil, topography, and vegetation) and identified eight soil types with distinct morphological, chemical, and physical attributes. The conventional soil survey identified thirteen soil classes, in the same eight landscape units, organized as soil associations. The apparent contradictions between local knowledge and Pedology were relative since the classification systems were established based on different criteria, goals, and sampling references. Most soils are only suitable for pasture, with restricted agricultural use, due to water or oxygen deficiencies. The current land use was only inconsistent with the technical recommendations when socioecological constraints such as the semiarid climate, land availability, and economic conditions for land management led to overuse of the land. Local knowledge demonstrated its legitimacy and allowed a useful and fruitful exchange of information with the academic view of soil-landscape interplays. Although mostly unknown by the scientific community, local knowledge proved capable of achieving social welfare and food security. In addition, a participatory survey proved to be a core factor for more grounded and detailed data collection on how Quilombolas decide land use on a local scale.

Methods for Quantifying Shrinkage in Latossolos (Ferralsols) and Nitossolos (Nitisols) in Southern Brazil

ABSTRACT Brown Nitossolos (Nitisols) and Latossolos (Ferralsols), according to the Brazilian System of Soil Classification (SiBCS), have a “carater retratil” as their distinctive property. Because this is a new topic, it is necessary to propose methods for evaluation. The objectives of this study were to evaluate methodologies for quantifying the shrinkage of soil using the Syringe Method and the Metallic Mercury Method, and to propose a new one, the “Ring with Sand Method”. Soil samples from eight pedons were used, [...]

Agricultural potential of areas under pasture in southern Tocantins

Improper soil use leads to inefficient exploitation of natural resources, destruction of land resources, poverty and other social problems. Therefore, the objective of this study was execute a survey and soil classification of an area under pasture in a farm in southern Tocantins. The area was divided according to the existing soil spots to perform the soil classification following the methodology of the Brazilian System of Soil Classification and its agricultural potential. At the studied area were found four soil classes, which were studied and classified as Plintossolo Argiluvico Distrofico petroplintico , Cambissolo Haplico Tb Eutrofico , Latossolo Vermelho-Amarelo Distrofico tipico and Gleissolo Melânico Ta Eutrofico with agricultural potential in the subgroups 1(a)bC, 4P, 1aBC and 3(bc), respectively. The terrain was underutilized, being used for pasture cultivation, at the same time it could be used for cultivation of annual plants.

CHARACTERIZATION OF YELLOW LATOSOLS (OXISOLS) OF SERRA DO QUILOMBO, IN PIAUÍ STATE SAVANNA WOODLANDS - BRAZIL

ABSTRACT The savanna woodlands of Piauí state has great economic importance since it is an area for agricultural expansion, being the fourth most important of Brazil and the first from Brazilian Northeastern. The area accounts for 5.9% of the Brazilian savanna woodlands and 36.9% of the Northeastern savanna, covering 46% of the Piauí state area, in a total of 11.5 million hectares. The goal of this research was to study pedoenvironments of Serra do Quilombo region, which is in Piauí state savanna, as well as identifying existing soil classes, according to the Brazilian System of Soil Classification - SiBCS. Soil identification consisted in characterizing soil profiles along a transect, assessing in-field conditions and collecting soil samples, in areas of native vegetation. The samples were gathered from three distinct points, being two at the edges and one at the center of the plateau. Soil analyses were carried out with samples collected from each horizon through trench digging up to a 2-m depth. Morphological, physical, chemical and mineralogical characterizations were performed for each soil profile, along with an evaluation of the effect of pedogenic factors on their formation and development. All soils under study were formed with source materials of the same geological formation; however, each rock has a distinct contribution to the process, involving sandstones and shales. The characteristics observed in the soil from Serra do Quilombo have no difference from the pattern found in the Brazilian plateaus, and soil profiles were classified as dystrophic clayey Yellow Latosols (Oxisols), according to the SiBCS.

CONDIÇÕES AMBIENTAIS DE FRAGMENTOS FLORESTAIS EM COMPARTIMENTOS GEOMORFOLÓGICOS E PEDOLÓGICOS EM PEQUENOS TRIBUTÁRIOS NO BAIXO JACUÍ

Fragmentos de Floresta Estacional Decidual Aluvial e Submontana encontram-se ao longo de um gradiente com uma grande variação geomorfológica e pedológica. Assim, para entender as condições nesses ambientes, foram estudadas de forma detalhada as condições de solos e as formas de relevo presentes em pequenos tributários de uma microbacia de geologia sedimentar, no município de Pantano Grande, Rio Grande do Sul. Para levantar essas variáveis foram instaladas 200 parcelas de 100 m² distribuídas em 40 pontos amostrais com 5 parcelas cada, desde as cabeceiras de drenagem até a planície de inundação do rio Jacuí. Em cada unidade amostral foram coletadas amostras superficiais de solos para análise de fertilidade e composição granulométrica. Foram determinadas 16 classes de solos até o quarto nível categórico e 12 compartimentos geomorfológico e pedológico. A análise de ordenação demonstrou diferenças entre os pontos amostrais da planície e vertentes. As variáveis, altimetria, declive, textura do solo, H + Al e CTC foram as mais importantes na análise da ordenação do ambiente.

Horizontes diagnósticos superficiais de Cambissolos e uso de δ13C como atributo complementar na classificação de solos

Resumo O objetivo deste trabalho foi avaliar os horizontes diagnósticos superficiais e quantificar os valores de δ13C em perfis de Cambissolos localizados em regiões de elevada altitude, em Santa Catarina, bem como propor a utilização complementar desse atributo no Sistema Brasileiro de Classificação de Solos (SiBCS). Foram realizadas coletas de amostras de horizontes superficiais de 24 perfis modais para a caracterização de atributos físicos e químicos. Para a determinação do δ13C, as coletas foram feitas nas camadas de 0,0-0,10, 0,10-0,20, 0,20-0,30, 0,30-0,40, 0,40-0,50, 0,50-0,60, 0,60-0,80 e 0,80-1,00 m. Predominaram os Cambissolos Háplicos com horizonte diagnóstico superficial A moderado e elevados teores de carbono orgânico total (COT). Os elevados valores de COT, no entanto, frequentemente não foram suficientes para classificação dos horizontes superficiais como A húmico, em razão de sua pequena espessura. Nos solos classificados como A húmico, os valores de δ13C revelaram pequena alteração na assinatura isotópica, indício de manutenção da vegetação; enquanto nos solos com A moderado observaram-se alterações decorrentes do cultivo. Sugere-se o uso de δ13C como atributo complementar para o SiBCS, e que o atributo profundidade seja desconsiderado, para fins de classificação, no caso de: alterações no uso do solo em áreas com declividade superior a 8%, solos rasos e pouco profundos, textura argilosa a muito argilosa e teores de COT superiores a 3%.

Characterization, classification and analysis of the main properties of the Southwestern Goias soil

Characterization of the soil and the grouping of its properties through main component analysis can assist in the classification and observation of the consequences of the conversion of native forest areas in pastures. Such data can aid in management practices. Considering the lack of studies in Cerrado soils of south-western Goias, developed metagranites of Jurubatuba suite, the objective was to classify and study the physical, chemical and mineralogical soil (under native forest and pasture) Southwest of Goias. Soil sampling and classification followed the Field Methods Manual and the Brazilian System of Soil Classification, respectively. The physical, chemical and mineralogical soil were studied, as well as main component analysis made for these attributes. The profile 1 under native forest was classified as “Cambissolo Háplico Tb eutrófico latossólico”. The profile 2 under degraded pasture was rated “Latossolo Amarelo eutrófico típico”. In addition, the profile 3 under rotated pasture was rated as “Latossolo Vermelho eutrófico chernossólico”. It was observed that the “Latossolos” have higher bulk density and soil penetration resistance, indicating greater soil compaction. They showed high amounts of iron oxides and minor amount of nutrients such as calcium and magnesium. The principal component analysis allowed the grouping of profiles into two groups. Group 1 brought together the properties related to “Latossolos”, and the second was related to “Cambissolo” properties. Thus, the principal components analysis aids the understanding of soil properties and the grouping of soils with similar characteristics, the level of order and management.

Genesis and Classification of Soils Containing Carbonates in a Toposequence of the Bambuí Group

The Bambui Group, formed from siliciclastic sediments deposited on an extensive epicontinental platform at the end of the Neoproterozoic era, is characterized by limestones with fine to very fine texture. Limestone-derived soils in the southeast of Tocantins state, Brazil, are less notorious than similar soils in other regions of Brazil and their characterization could contribute to the Brazilian System for Soil Classification (SiBCS). Given that little is known of these soils, despitetheir agricultural potential, the objective of this study was to characterize their properties and the processes leading to soil of genesis, and also contribute to developing the Brazilian System of Soil Classification (SiBCS). Soils profiles were located on the summit (P1), shoulder (P2), backslope (P3), and footslope (P4) of a toposequence in the municipality of Lavandeira, Tocantins. Morphological, physical, chemical, and mineralogical properties of the profiles were determined. The soils were classified as: P1 - Chernossolo Rendzico Litico tipico (Lithic Haplustolls); P2 - Cambissolo Haplico Ta Eutrofico leptico hipocarbonatico (Lithic Haplustolls); P3 - Cambissolo Haplico Carbonatico leptico (Lithic Haplustepts); and P4 - Luvissolo Haplico Ortico tipico (Typic Rhodustalfs). All the profiles showed high contents of silt, calcium, and magnesium, which resulted in high pH and low exchangeable aluminum content. Base saturation and calcium carbonate equivalent contents were also high, and the horizons showed dark colors due to high organic matter content, which contained humin as the dominant fraction. Mineralogical analysis of the clay fraction indicated predominance of hydroxy-interlayered vermiculite, followed by illite, kaolinite, and quartz, whereas the sand fraction exhibited reflections characteristic of the quartz mineral. Given P4 contents of calcium carbonate equivalent above 50 g kg-1 and the relevance of this feature for agriculture, we propose the inclusion of hypocarbonate as a criterion for classification of Luvissolos Haplicos Orticos at the subgroup level.

Genesis and Classification of Soils from Subtropical Mountain Regions of Southern Brazil

Soils formed in high mountainous regions in southern Brazil are characterized by great accumulation of organic matter (OM) in the surface horizons and variation in the degree of development. We hypothesized that soil properties and genesis are influenced by the interaction of parent materials and climate factors, which differ depending on the location along the altitudinal gradient. The goal of this study was to characterize and classify the soil, evaluate soil distribution, and determine the interactive effects of soil-forming factors in the subtropical mountain regions in Santa Catarina state. Soil samples were collected in areas known for wine production, for a total of 38 modal profiles. Based on morphological, physical, and chemical properties, soils were evaluated for pedogenesis and classified according to the Brazilian System of Soil Classification, with equivalent classes in the World Reference Basis (WRB). The results indicated that pedogenesis was strongly influenced by the parent material, weather, and relief. In the areas where basic effusive rocks (basalt) were observed, there was formation of extensive areas of clayey soils with reddish color and higher iron oxide contents. There was a predominance of Nitossolos Vermelhos and Haplicos (Nitisols), Latossolos Vermelhos (Ferralsols), and Cambissolos Haplicos (Cambisols), highlighting the pedogenetic processes of eluviation, illuviation of clay, and latosolization in conditions of year-long, large-volume, well-distributed rainfall and stability of land forms. In areas with acid effusive rocks (rhyodacites), medial or clayey soils were observed with lower iron oxide content, invariably acidic, and with low base content. For these soils, relief promoted substantial removal of material, resulting in intense rejuvenation, with a predominance of Cambissolos Haplicos (Cambisols) and lesser occurrence of Nitossolos Brunos (Nitisols) and Neossolos Litolicos (Leptosols). Soils formed from sedimentary rocks also tended to be more acidic, but with higher sand content, and the soils identified were Cambissolos Haplicos and Humicos (Cambisols). Cluster analysis separated the soil profiles into three groups: the first and largest was formed by profiles originating from sedimentary rocks and rhyodacites; the second, smaller group was formed by four profiles in the Agua Doce region (acidic rocks); and the third was formed by profiles derived from basalt. Discriminant analysis was effective in grouping soil classes. Thus, the study highlighted the importance of geology in the formation of soils in this landscape associated with climate and relief.

Genesis and Classification of Soils Containing Carbonate on the Apodi Plateau, Brazil

Information is scarce on the genesis and classification of soils derived from calcareous rocks in the Northeastern region of Brazil. This study describes the morphological, physical, chemical, mineralogical, and micromorphological properties of four soil profiles (P1-P4) located in the Apodi Plateau. A pedogenesis hypothesis and soil classification, according to the Brazilian System of Soil Classification (SiBCS), are proposed for these profiles. The interactions between parent material, surface topography and climate affected the pedogenesis processes and soil properties, although the calcareous nature of the parent material most affected the soil morphology and chemical properties. The sand fraction contained mainly quartz and calcite, and a smaller amount of mica. Smectite and interstratified illite-smectite occurred in the clay fraction of profile P1 and in some horizons of P2 (Ccmќ and Ccrќ) and P3 (2Ccrќ). Kaolinite predominated in profiles P2, P3, and P4; where as illite and vermiculite were present in the Bicќ, Bcќ, Bcmќ horizons of P2, in Bt2c of P3, and in C of P4. The mineralogy showed illite, hematite, and goethite, and anatase in a number of horizons. Micromorphological analysis of P2 indicated a strong cementation of Bcmќ and Ccmќ by calcium carbonate, and other properties indicate the formation of a petrocalcic horizon, but this horizon lacked lateral continuity in the profile. Therefore, the parapetrocalcic term is proposed for classifying P2 in the fourth level of the SiBCS. The 3Biќ-P1 horizon exhibited calcite coating and iron coating or quasi-coating, indicating distinct pedogenesis processes occurring under different environmental conditions. Likewise, the occurrence of petroplinthite in P2 indicates that climatic conditions during its formation differed from present conditions, and both situations are interpreted as evidence that the soils were formed by polygenetic processes. In the SiBCS classification, the soils are classified as Cambissolo Haplico Carbonatico vertissolico (P1), Cambissolo Haplico Carbonatico concrecionario (P2), Luvissolo Cromico Palico petroplintico (P3), and Neossolo Litolico Carbonatico tipico (P4); and a new class (parapetrocalcico concrecionario) is proposed for P2 in the fourth level.

Histosols in an Upper Montane Environment in the Itatiaia Plateau

Highland environments favor accumulation and preservation of soil organic matter (SOM) due to low temperatures, leading to the formation of Histosols. The Itatiaia National Park (INP), Rio de Janeiro, Brazil, offers conditions for preservation of SOM deposited over time, which has led to the formation of these soils. The objective of this study was to characterize Histosols in this environment, with the premise that it may provide evidence of changes in vegetation. Organossolos (Histosols) were sampled, characterized, described, and analyzed for their properties, stable isotopes of 12C and 13 14 15 14 C, N and N, and dating of organic matter through C. The soils were classified in the Brazilian Soil Classification System as Organossolo Háplico Hêmico típico - RJ-01 (Haplohemists) and Organossolo Fólico Sáprico cambissólico - RJ-02 (Udifolists). The morphological properties, degree of transformation, and chemical fractioning of SOM were consistent with hemic and sapric materials. The δ13C and δ15N isotopic analyses showed a difference in the contribution of plant materials. In RJ-01, there was previous influence of algae, due to poor drainage, and depletion of δ13C, suggesting a mix of C3 and C4 plants. RJ-02 showed influence of C3 type plants. The 14C dating for RJ-01 was 3280±80 years, and for RJ-02, 2005±5 years (modern age).

SOIL VARIABILITY IN DIFFERENT LANDSCAPE POSITIONS IN THE PORTO ALEGRE BOTANICAL GARDEN, SOUTHERN BRAZIL

ABSTRACTKnowledge of soil characteristics in areas where activities related to the environment are developed, such as Porto Alegre Botanical Garden (JB-PoA), is a fundamental condition for the sustainable use of this natural resource. The objective of this study was to characterize, classify and evaluate some issues about soil formation in Porto Alegre Botanical Garden, as well as relate their distribution on the landscape according to environmental characteristics. For the morphological description and collecting samples four profiles were selected (P1 to P4), located in the summit-shoulder transition, backslope, footslope and toeslope, respectively. Granulometric distribution of the P1 and P3 profiles indicated sharp textural gradient, with presence of textural and "plânico" B horizons, respectively, according to Brazilian System of Soil Classification. There is predominance of low values of pH, and low base saturation, with exception of P4, indicating probable deposition of solution material at this area. The Fed/Fes relationship was greater in the profile located in the summit-shoulder transition (P1), indicating higher weathering. The Feo/Fed relationship increased in P3 and P4 profiles, indicating greater participation of iron oxides of low crystallinity in reducing environment. The occurrence of some pedogenic processes may be inferred, like lessivage in P1 (Ultic Hapludalf), due to clay skins and higher values of fine clay:total clay relationship in subsurface; ferrolysis and gleization, by low pH value and high Feo/Fed relationship in E and EB horizons of P3 (Oxyaquic Hapludalf), being the last also present in P4 (Humaqueptic Endoaquent), indicating gleization occurrence.

Genesis, Characterization, and Classification of Mangrove Soils in the Subaé River Basin, Bahia, Brazil

ABSTRACT Preservation of mangroves, a very significant ecosystem from a social, economic, and environmental viewpoint, requires knowledge on soil composition, genesis, morphology, and classification. These aspects are of paramount importance to understand the dynamics of sustainability and preservation of this natural resource. In this study mangrove soils in the Subaé river basin were described and classified and inorganic waste concentrations evaluated. Seven pedons of mangrove soil were chosen, five under fluvial influence and two under marine influence and analyzed for morphology. Samples of horizons and layers were collected for physical and chemical analyses, including heavy metals (Pb, Cd, Mn, Zn, and Fe). The moist soils were suboxidic, with Eh values below 350 mV. The pH level of the pedons under fluvial influence ranged from moderately acid to alkaline, while the pH in pedons under marine influence was around 7.0 throughout the profile. The concentration of cations in the sorting complex for all pedons, independent of fluvial or marine influence, indicated the following order: Na+>Mg2+>Ca2+>K+. Mangrove soils from the Subaé river basin under fluvial and marine influence had different morphological, physical, and chemical characteristics. The highest Pb and Cd concentrations were found in the pedons under fluvial influence, perhaps due to their closeness to the mining company Plumbum, while the concentrations in pedon P7 were lowest, due to greater distance from the factory. For containing at least one metal above the reference levels established by the National Oceanic and Atmospheric Administration (United States Environmental Protection Agency), the pedons were classified as potentially toxic. The soils were classified as Gleissolos Tiomórficos Órticos (sálicos) sódico neofluvissólico in according to the Brazilian Soil Classification System, indicating potential toxicity and very poor drainage, except for pedon P7, which was classified in the same subgroup as the others, but different in that the metal concentrations met acceptable standards.

Integrating geospatial and multi‐depth laboratory spectral data for mapping soil classes in a geologically complex area in southeastern Brazil

SummarySoil mapping across large areas can be enhanced by integrating different methods and data sources. This study merges laboratory, field and remote sensing data to create digital maps of soil suborders based on the Brazilian Soil Classification System, with and without additional textural classification, in an area of 13 000 ha in the state of São Paulo, southeastern Brazil. Data from 289 visited soil profiles were used in multinomial logistic regression to predict soil suborders from geospatial data (geology, topography, emissivity and vegetation index) and visible–near infrared (400–2500 nm) reflectance of soil samples collected at three depths (0–20, 40–60 and 80–100 cm). The derived maps were validated with 47 external observations, and compared with two conventional soil maps at scales of 1:100 000 and 1:20 000. Soil suborders with and without textural classification were predicted correctly for 44 and 52% of the soil profiles, respectively. The derived suborder maps agreed with the 1:100 000 and 1:20 000 conventional maps in 20 and 23% (with textural classification) and 41 and 46% (without textural classification) of the area, respectively. Soils that were well defined along relief gradients (Latosols and Argisols) were predicted with up to 91% agreement, whereas soils in complex areas (Cambisols and Neosols) were poorly predicted. Adding textural classification to suborders considerably degraded classification accuracy; thus modelling at the suborder level alone is recommended. Stream density and laboratory soil reflectance improved all classification models, showing their potential to aid digital soil mapping in complex tropical environments.

ATRIBUTOS FÍSICOS DE UM NITOSSOLO VERMELHO CULTIVADO COM TRIGO, EM SISTEMA PLANTIO DIRETO, SUBMETIDO À COMPACTAÇÃO E ESCARIFICAÇÃO - DOI: 10.13083/1414-3984/reveng.v23n1p19-28

A compactação do solo é comumente observada em solos cultivados no sistema plantio direto, podendo causar reduções na produtividade das culturas devido às limitações no crescimento radicular. O estudo objetivou avaliar a influência de níveis de compactação do solo, na produtividade de trigo cultivado em um Nitossolo Vermelho distroférrico úmbrico. O experimento foi realizado na Estação Experimental da Universidade Tecnológica Federal do Paraná (UTFPR), Campus Dois Vizinhos, PR, Brasil. Os tratamentos consistiram: sistema do plantio direto (PD), plantio direto com compactação adicional (PDA) e plantio direto com escarificação mecânica (PDE). Avaliou-se a densidade, a porosidade e a resistência do solo a penetração a cada 0,05 m até a profundidade de 0,25 m, bem como a produtividade do trigo, a massa de grãos e o peso hectolitro. Constatou-se que na camada superficial do solo ocorreram as menores densidades de solo (Ds), maior macroporosidade e porosidade total nas três situações, sendo que nas camadas inferiores a 0,05 m os tratamentos PD e PDA, superaram o valor crítico 1,30 kg dm-3 para solos muito argilosos. A compactação adicional ao sistema plantio direto afetou negativamente as propriedades físicas do solo, na sua camada superficial, acima de 0,05 m, sendo observados incrementos de densidade do solo, na resistência à penetração e redução da macroporosidade e porosidade total. A escarificação mecânica melhorou as propriedades físicas do solo até a profundidade de 0,1 m, após treze meses de intervenção, superando os demais sistemas avaliados. Entretanto, o uso do implemento subsolador, como forma de reduzir a compactação do solo, não contribuiu para o aumento da produtividade e a qualidade dos grãos de trigo.