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In the last decades, the studies involving the mechanisms of the CO2 emissions dynamics have been studied in several ecosystems with varied soil classes. The objective of this study was to evaluate the relationship between physical and chemical attributes of soils and the variation of CO2 efflux in Indian Black Earth (IBE) and non-anthropogenic soils in the Amazon. The study areas are located in the southern region of Amazonas, specifically in the municipalities of Humaitá and Apuí. Respectively in the natural field and forest areas, grids with dimensions of 70 m x 70 m and 10 m regular spacing between sample points, in the depth of 0.0–0.20 m, totaling 64 samples were delimited. In the IBE area, a 42 x 88 m grid was established, marking points at a 6 x 8 m spacing, totalizing 88 sampling points in the depth of 0.0–0.2 m. The soil physical analyzes performed were bulk density, soil penetration resistance, macroporosity, microporosity, total porosity and texture, and the soil chemical analyzes were composed by organic carbon, organic matter and carbon stocks. The soil CO2 emission (FCO2) was recorded with a portable automated LI-COR soil flow system (LI-8100). The soil temperature (Tsolo) was monitored concomitantly with the soil CO2 emission evaluations using a temperature sensor that is an integral part of the LI-8100 system. Soil moisture was recorded using a Time Domain Reflectometry (TDR) apparatus - Campbel® Hydrosense ™ Campbell Scientific. The data were submitted to descriptive statistical analyzes and multiple linear regression with the pedotransfer functions model criterion. The study demonstrates the variation of physical and chemical attributes of the soil and its influence on CO2 efflux variation, since the different environments studied presented differentiated scales and attributes for each situation, due to the correlations presented.

Extrações sequenciadas ou fracionamento químico de metais pesados permitem inferências sobre origem, forma de ocorrência, biodisponibilidade, potencial de toxicidade e contaminação ambiental por esses elementos. Assim, o presente estudo foi desenvolvido com o propósito de avaliar a distribuição de Cu, Mn, Ni, Pb e Zn entre as diferentes frações do solo e compartimento da paisagem, de um Latossolo Amarelo sob cultivo de hortaliças. Foram coletadas amostras de solos de cinco áreas cultivadas com tomate (Lycopersicon esculentum, Mill.), alface (Lactuca sativa), pimentão (Capsicum annuum L.) e acelga (Beta vulgaris L.) em diferentes posições no relevo (topo, encosta, baixio) e quatro áreas de referência (mata nativa), na profundidade de 0,00 - 0,20 m. Também foram avaliados os teores de metais pesados na água destinada à irrigação das lavouras e ao consumo humano, coletando-se para isso, 200 ml de amostras de água dos reservatórios. As amostras de solo foram fracionadas sequencialmente para quantificação dos teores de Cu, Mn, Ni, Pb e Zn adsorvidos às frações trocável (FT), matéria orgânica (FO), óxido de ferro amorfo e cristalino (OxFeA e OxFeC). As posições da paisagem interferiram significativamente na adsorção de metais pesados no solo apenas para o Cu e o Ni ligados à OxFeC e para o Zn ligado à FT, nas áreas cultivadas. Os maiores teores de Cu, Ni, Pb e Zn no solo encontram-se nas frações com ligações químicas menos estáveis (ligados à matéria orgânica) sendo também encontrada forte afinidade de Cu, Zn e Mn às frações oxídicas (AFeOx + CFeOx). A baixa afinidade de Pb e Ni às OxFeA e OxFeC condiciona maior potencial de contaminação dos reservatórios hídricos. A curto prazo, a matéria orgânica é a principal fonte de remediação de metais pesados no solo, sendo importante a adoção de práticas conservacionistas que reduzam suas perdas.

Heavy metals occur naturally in the soil as a product of rock weathering and, are commonly associated with environmental pollution and toxicity to living beings. This association deserves much attention since some heavy metals, such as Fe, Mn, Cu, Zn, and Ni, are essential to plants. Our attention should thus be drawn not only to the element itself, but also to its contents in the soil. This is because its occurrence and quantities are covariates of the geomorphic, geologic, pedologic, and anthropogenic diversity. In this context, the present study aimed to determine the natural contents of heavy metals in the soils of three physiographic regions of the south of Amazonas state, comparing them to natural contents in some other Brazilian soils. Twenty-four soil samples were collected in three physiographic regions (field/forest, animated relief, and flooded/non-flooded areas), in the superficial and subsurface horizons. The digestion of the samples was based on the EPA-3051A method and the determination by atomic absorption spectrophotometry (AAnalyst 800 Perkin Elmer). The results indicate a low potential of soils from the south of Amazonas in supplying heavy metals, which were found in the following decreasing order: Ba > Fe > Cr > Pb > Zn > Cu > Mn > Co > Cd. The natural heavy metal contents vary depending on the type of soil, weathering level, and physiographic regions, and are similar or inferior to those observed in other regions of the country; with Neosols presenting the highest natural contents; and Cambisols, the lowest, for most of the metals evaluated.

O conhecimento da distribuição espacial da temperatura, umidade do solo e emissão de CO2 é fundamental para entender o solo como fonte ou dreno de CO2, pois as alterações quanto ao uso e manejo influenciam esta dinâmica. O presente trabalho teve como objetivo investigar, a temperatura, umidade do solo e emissão de CO2 em uma área sob pastagem na região de Humaitá, AM. Demarcou-se uma área de 70 x 70 m, com espaçamento regular de 10 m, totalizando 64 pontos, as medições foram realizadas no período chuvoso e seco. Emissão de CO2 e a temperatura do solo foram registradas utilizando-se de câmara de fluxo portátil e sensor de temperatura do sistema LI-COR (LI-8100). A umidade foi avaliada utilizando sistema portátil TDR, em seguida foram realizadas análises estatísticas descritivas e geoestatísticas. A área de pastagem apresentou maior emissão de CO2 do solo no primeiro período de coleta, caracterizado como período chuvoso. Variações espaciais da emissão de CO2 estão intimamente relacionadas com as variáveis climáticas entre os períodos seco e chuvoso.

The Archaeological Dark Earth (ADE) are soils that can hold up to six times more organic carbon than surrounding soils without anthropic horizons, thus assuming higher CO2 emissions from these soils. The objective of this study was to investigate the spatial distribution of CO2 efflux, temperature and soil moisture in an Archaeological Dark Earth area under cocoa and coffee cultivation in the municipality of Apuí, AM, Brazil. Sample grids of 42 x 80 m were set up, with space between points of 8 x 6 x 10 m and 10 m, respectively, for the cocoa and coffee areas. After data of CO2 efflux, temperature and humidity of the soil were collected, descriptive statistics and geostatistics analyses were done. The results showed that the evaluated parameters exhibited spatial dependence reaching a range of 25 to 40 m for CO2 stream ADE area with cocoa. The CO2 efflux in the cocoa area was higher, with an average value of 5.49 µmol m-2 s-1, compared to 3.99 µmol m-2 s-1 in the area of coffee CO2.

Os metais pesados ocorrem naturalmente no solo como produto do intemperismo das rochas e, comumente, são associados com poluição ambiental e toxidade aos seres vivos. Essa relação merece atenção mais cautelosa, uma vez que alguns são essenciais às plantas como Fe, Mn, Cu, Zn e Ni. Assim, a preocupação deve estar voltada não apenas ao elemento em si, mas aos teores desses no solo, visto que sua ocorrência e quantidade são covariativas da diversidade geomorfológica, geológica, pedológica e antrópica. Neste sentido, objetivou-se determinar os teores naturais dos metais pesados nos solos de três regiões fisiográficas da região Sul do Amazonas, comparando-os com os teores naturais de alguns solos do país. Foram coletadas 24 amostras de solo em três regiões fisiográficas (Campo/Floresta, Relevo Movimentado e Várzea/Terra Firme), nos horizontes superficiais e subsuperficiais. A digestão das amostras baseou-se no método EPA-3051A, e a determinação com espectrofotometria de absorção atômica (AAnalyst 800 Perkin Elmer). Os resultados indicam baixo potencial dos solos do Sul do Amazonas em suprir metais pesados, sendo os maiores teores encontrados na seguinte ordem decrescente: Ba > Fe > Cr > Pb > Zn > Cu > Mn > Co > Cd. Os teores naturais de metais pesados variam em função da classe de solo, grau de intemperismo e das regiões fisiográficas e são semelhantes ou inferiores aos observados em outras regiões do país; com Neossolos apresentando teores naturais mais elevados e, os Cambissolos, os mais baixos, para a maioria dos metais avaliados.

A configuração da paisagem favorece o entendimento do comportamento dos atributos texturais, sendo influenciada em menor escala pelos segmentos de vertente, pois a migração de sedimentos, água e nutrientes obedecem aos processos geológicos superficiais e ao intemperismo. Diante disso, objetivou-se com esse trabalho caracterizar a variabilidade espacial da textura em uma área irrigada por pivô central em diferentes posições na paisagem da região de Cristalina-GO. Foram realizadas amostragens do solo em intervalos regulares de 10 m, em forma de malha, totalizando 180 pontos, em diferentes posições da paisagem. As amostras foram coletadas s nas profundidades de 0,00-0,10 m, 0,10-0,20 m e 0,20-0,30 m para a determinação dos teores de argila, silte e areia. Os dados foram submetidos à análise estatística descritiva, geoestatística e interpolação por krigagem. Os resultados demonstram que a migração de partículas seguiu o fluxo de água na vertente causando o transporte seletivo de sedimento, o que implica em maior erosão de sedimentos, água e nutrientes. As formas da vertente condicionaram o movimento e a concentração das partículas do solo. A migração de argila para camadas subsuperficiais do solo é relacionada com a gênese do solo e ao carreamento de partículas pela água.

Abstract The south of the Brazilian Amazon is one of the largest cattle-producing regions in Brazil, however, most of the pastures are in low fertility soils. Thus, cattle breeders compensate for the low production of pastures, increasing the size of the areas, generating more deforestation and burning. These practices increase the chemical degradation process of Amazonian soils, making them increasingly infertile when improperly managed. With this, the objective of the work was to evaluate the impacts caused in the chemical attributes of soils, in areas under forest-to-pasture conversion, in the south of the Brazilian Amazon. The study was carried out in the district of União Bandeirantes, in an area of forest and two areas with pastures (brachiaria and mombaça grass). In the field, soil samples were collected at two depths (0.00–0.10 and 0.10–0.20 m), to carry out chemical analyzes. Further, uni, bi and multivariate statistical analyzes were carried out, besides geostatistical analyzes were carried out to study spatial variability and management zones. The conversion of forest to pasture increased the pH and exchangeable bases levels, reducing the availability of exchangeable aluminum and potential acidity, however, it induces losses of phosphorus and organic carbon from the soil. Among the pasture environments, the mombaça grass area presented higher fertility. Greater spatial variability of chemical attributes was observed in the environment with mombaça grass, indicating greater heterogeneity in the distribution of attributes in the area. We attribute this behavior to the higher grazing intensity and the micro-reliefs in the area that direct the flow of water and nutrients.

“Erodibility” is a characteristic of the soil that represents the susceptibility with which its particles from the most superficial layer are taken and transported to lower places by erosive agents, causing environmental and economic damages. This work estimated soil erodibility in pastures and forest areas in the municipality of Porto Velho-Rondônia. In the field, three areas with different types of vegetation were selected, one with brachiaria, another with mombaça grass, and a third in native forest. In areas with pastures, a sampling mesh of equal sizes was outlined (90 m x 60 m), and in the forested area an approximate sampling mesh (90 m x 50 m), with a regular spacing of 10 m between the samples points for both areas. The sampling was done at the crossing points of the mesh at a depth of 0.0-0.2 m, composing 70 sample points in the areas with pastures and 60 sample points in the forest area, totaling 200 samples. Then, laboratory analyzes were carried out to determine the texture followed by the fractionation of the sand, and the organic carbon followed by the estimate of the organic matter of the soil. The erodibility factors were calculated using indirect prediction models, and then, univariate, geostatistical and multivariate techniques were applied. The pastures’ environments differed from the forest environment. However, the mombaça grass area functions as an intermediate environment between the forest and the brachiaria, being closer to the forest environment.

The Amazon rainforest region presents a phytophysiognomy that ranges from savannas to cerrados, all of them intimately associated to climate and soil characteristics. Evidence has been given that plant growth and development are affected by soil quality and seasonality, thus making it crucial to understand them and how they are related to each other in order to grasp the dynamics of the whole ecosystem. In this context, the goal of this research was to assess how seasonality, soil attributes, and root system biomass are related in natural cerrado, cerradão, and forest areas in southern Amazonas State, in Brazil. Soil samples were collected during dry (June/2018) and rainy (December/2018) seasons from three different layers 0.00–0.05m; 0.05–0.15m, and 0.15–0.30m deep. In each area ten sampling points were randomly chosen. Two kinds of soil samples were collected: the first using 4.0 cm height by 5.1cm internal-diameter soil sample rings; and the second were intact soil lumps. Physical and Chemical soil attributes assessed were macro-porosity (MaP), micro-porosity (MiP), total porosity (TP), soil density (SD), aggregates texture and stability (GMD and WAR), gravimetric humidity (HG), organic carbon (OC), exchangeable aluminum (Al3+), potential acidity (H+Al), sum of bases (SB), cation exchange capacity (CEC), and root biomass (RB). All data were analysed via Tukey t test and student T test to compare results between seasons and areas. Increasing vegetation density (cerrado < cerradão < forest) was followed by an increment in CEC and OC, showing the importance of these attributes to maintaining biodiversity in environments. In amazon cerrado, rainy season as well a sandier soil textures provided favourable conditions to the growth and development of plants’ root system. Soil attributes were little affected by seasonality, that had greater effect on MiP, TP, SD, and OC, leading to lesser values for these variables during rainy season.

As terras pretas arqueológicas estão presentes em toda região amazônica, são solos férteis, que possuem textura variando de arenosa a argilosa. Um dos fatores de formação que influenciam na variabilidade espacial da fertilidade e textura desses solos é o relevo, através dos processos de remoção e adição de partículas e nutrientes. Desta forma, o objetivo deste trabalho foi avaliar a influência do relevo na distribuição espacial da textura e fertilidade do solo em uma área de Terra Preta Arqueológica (TPA) em Novo Aripuanã, AM. Em campo, foram coletadas amostras de solo em área de floresta, nas posições da encosta: terço superior, médio e inferior. Em laboratório, foram realizadas as análises químicas e texturais das amostras, posteriormente foram feitas as análises estatísticas uni e multivariada e também a análise geoestatística. Constatou-se que o relevo influenciou na variabilidade espacial dos atributos Ca2+, Mg2+, carbono orgânico, silte e argila e que o processo de lixiviação causada pela topografia não influenciou os teores de carbono orgânico e o fósforo disponível no solo. Esses resultados possibilitam estabelecimento de zonas de manejo tornando o solo mais adequado e sustentável à agricultura e desenvolvimento florestal.

Soil-landscape relationships in natural environments can provide helpful insights into soil suitability and limitations and necessary changes regarding agricultural land use and management. The objective of this work was to verify soil variations along a sandstone-gneiss lithological toposequence in the western Amazonian region of Brazil. Within this topolithosequence, the following soil profiles were sampled: CAMBISSOLO HÁPLICO (Dystric Leptic Cambisol), NEOSSOLO REGOLÍTICO (Cambic, Lithic, Leptosol), NEOSSOLO QUARTZARÊNICO (Dystric Regosol), PLINTOSSOLO PÉTRICO (Petric, Plinthosol), and ARGISSOLO AMARELO (Chromic, Abruptic, Acrisol). These profiles were located on the following slope segments: interfluve (P1), convex creep slope (P2), transportational midslope (P3), colluvial footslope (P4), and alluvial toeslope (P5). Soil analyses included physical and chemical attributes. The influence of the landscape on soil attributes was evaluated through randomness test, run charts, Pearson correlation, and Tukey test at a 5% significance level. Soil chemical properties were more sensitive to slope-related variations, with increased chemical quality in P2 for both horizons. Soil organic matter proved to be crucial for improving the chemical and physical quality of sandstone soils.

Archaeological Dark Earth (ADE) soils are rich in organic matter and highly fertile, but when used for farming or grazing activities, they generally lose chemical and physical quality, becoming more susceptible to erosion. In this context, this study aimed to evaluate the changes in physical properties of the soil in different management systems adopted in ADE areas of the Amazon. The study area is located in the municipality of Novo Aripuanã, in the mesoregion of Madeira, south of the state of Amazonas. Three ADE areas were selected: 1—native forest (Amazon forest fragment); 2—area covered with Brachiaria (Urochloa brizantha cv. Marandu), without the addition of fertilizers or soil improvers; and 3—area covered with pigeon pea (Cajanus cajan) and other commercial crops (corn, beans, and watermelon). The following soil characteristics were evaluated: soil resistance to penetration, soil bulk density, macroporosity and microporosity, and total soil porosity in the 0–0.20 m and 0.20–0.40 m layers. The results showed that the pasture area presented a smaller amount of total pores and complex pores, which are important for water flow in the soil. The areas analyzed in this study presented no critical obstacle to plant root development with the low value of resistance to penetration (

Abstract Agriculture needs methodologies that assist in the determination of soil attributes and variability mapping attributes with greater levels of detail. Therefore, the objective of this research was to evaluate magnetic susceptibility as auxiliary variable for estimating soil attributes in areas of Indian Black Earths in the south of Amazonas State. Three Indian Black Earth areas are located in the municipalities of Apuí and Manicoré - Amazonas, under uses with coffee, cocoa and pasture. The soils were collected at the crossing points in the depth of 0.00 - 0.20 m, making a total of 88 sampling points/area, and totaling 264 samples. The points were georeferenced for geostatistical modeling. After that, physical and chemical analyzes were performed to obtain the values of soil and magnetic susceptibility attributes. Descriptive statistics, Pearson correlation, linear regression and geostatistical analyzes were applied for Pedotransfer Function modeling and the spatial variability of the analyzed attributes. Magnetic susceptibility showed a high degree of spatial dependence in the study areas, high range values, correlating with most of the assessed attributes, mainly physical, indicating potential in the prediction of the attributes in these environments. Pedotransfer functions vary among IBE’s sites in attribute prediction, ensuring moderate estimates for predicting soil attributes in IBE’s areas.

ABSTRACT The soils of the Amazon region, despite being under one of the densest forests in the world, are mostly characterized by the low availability of nutrients, with litter being the main route of nutrient entry. The objective of this study was to quantify the biomass of fine roots in the dry and rainy seasons of the year, including the organic carbon of the soil, and to compare the results in different study environments. The study was carried out in environments of native forest and reforestation aged over 20 years, located in the municipality of Humaitá – AM state. To assess the root biomass, collections were carried out in two periods of the year: dry and rainy seasons. In each of the study areas, five trenches, 0.40 m deep by 0.40 m wide, were dug manually at depths of 0-5, 5-15, and 15-30 cm. For the organic carbon analysis, soil samples were collected in the form of clods at the same depths. The production of root biomass in the native forest environment occurred more intensely in the rainy season, reaching values of 8.19 t. ha-1, greater than 3.57 t. ha-1 found in reforestation. The density as a function of the soil volume showed that the highest concentration is found in the first 5 centimeters of depth, differing significantly in the 5-15 and 15-30 cm layers for native forest area. The organic carbon of the soil showed significance between the dry and rainy seasons for the natural forest environments and reforestation with genipap.

The process of converting natural ecosystems in cultivated areas, as well as use and land management systems have provided changes in aggregate stability and soil carbon stocks levels. The objective of this work was to evaluate the stability of aggregates and carbon stock in areas under forest conversion to different cropping systems, using statistical tools. Grids were established according to the culture dimensions, samples were taken at the crossing points of the grids at depths 0.00–0.05; 0.05–0.10; and 0.10–0.20 m, with 80 sampling points in each area, totaling 240 per area. At each sampling point, samples were collected with a preserved structure in the shape of a clod to determine the physical and chemical attributes, with a total of 960 samples in the four areas evaluated. The conversion process influenced soil aggregation, as measured by increased clay fraction dispersion and decreased WAD, GAD and aggregate classes >2.00 mm; The attributes were shown at the limit of the degree of spatial dependence, varying from moderate to strong; In the multivariate analysis, the forest and cupuaçu areas presented similar behavior, with values of OC, CS, silt, clay and classes of aggregates 2–1 mm,

The recognition of the influence of management practices on soil physical and chemical conditions is substantial for sustainable agriculture. For this reason, this study was developed for the purpose of evaluating the behavior of soil attributes under different uses in the region of Humaitá, AM, using multivariate statistical methods. The study was developed in 8 rural properties producing bananas, grassland, maize, coffee, cassava, vegetables, agroforestry system and a forest fragment. Samples of soils with preserved structure in the 0.0 - 0.10 and 0.10 - 0.20 m layers were randomly collected in 5 small trenches per area, totaling 32 samples in the management systems, to determine the physical and chemical attributes. The data were then submitted to univariate and multivariate statistical analysis. Exploratory data analysis (principal components and dendrogram) and frequency of environmental covariates was efficient in distinguishing production environments, so multivariate classification based on physical and chemical attributes of the soil can help in the proper planning of land use. The analysis of the principal components indicates that the BD presents direct dependence with the SPR, signaling the use of the soil with grassland the only one in the process of compaction. Soil acidity is the main limiting factor for crop development, requiring the adoption of pH corrective practices with improvements in nutrient supply. The conversion of the forest to grassland maintained the structural characteristics of the soil, while the other uses increased improvements in physical quality and soil fertility.

The crop systems adopted in the Amazônia region have been studied several times in terms of the variability and to indicate the soil attributes more sensitive to the different crops. Thus, the objective of this work was to apply multivariate techniques in order to identify the chemical attributes most sensitive to environmental changes in different crop systems in Western Amazonia, Brazil. The research was conducted in five rural properties located in the Humaitá city region, Western Amazonia, Brazil. There were selected four environments with natural characteristics (Native Forest - NF) and five cropping systems (Grazing, Cassava, Açaí, Agroforestry and Reforestation). In the selected areas, soil samples were collected at depths layers of 0.0-0.05 m; 0.05-0.1 m and 0.1-0.2 m and the following chemical analyzes were performed: pH in water, Ca2+, Mg2+, K +, Resin-P, phosphorus bio-available particulate (Pbp), OC, Al3+, H++Al3+ and from these results SB, T, t, m% and V% were calculated. Multivariate statistical techniques were used to verify similarities between the crop systems in the attempt to relate the crops grown and the chemical attributes. The multivariate analysis was essential in the crop systems distinction, as well as to describe the relationship with the chemical properties. The results demonstrate and reinforce the existing variability between crop systems, with emphasis on the variation in crop systems, compared to natural environments.

Studying particle size distribution is important to understand soil structure and formation processes. This research aimed to assess the fractal dimension of soil texture in Indian Dark Earth (IDE) areas in southern Amazonas state under different land uses, as follows: two areas in the municipality of Apuí, one growing cocoa and the other coffee; a grassland area in the municipality of Manicoré; and a forest area in the municipality of Novo Aripuanã. A sampling grid containing 88 collection points (intersecting points on the grid) was established in each area, measuring 80 x 42 m for the cocoa and coffee-growing sites, and 80 x 56 m and 60 x 42 m for the grassland and forest areas, respectively. Soil samples were collected in soil core and as clumps at a depth of 0.0-0.20m to determine the structural physical properties and texture of the soil. The following physical attributes were assessed: texture (PSD), bulk density (BD), macroporosity (Macro), microporosity (Micro), total porosity (TP) and aggregate stability (GMD and WMD). The fractal dimension (D) of the soil texture was determined, followed by analysis of variance and comparison of the means using Tukey’s test (p≤0.05). Pearson’s correlation was applied to assess the correlation between variables. There was a significant difference between the IDEs studied, with a higher D value in the cocoa-growing area in relation to the other sites. Additionally, the larger the clay fraction, the higher the D value. Fractal dimension (D) showed a positive correlation with sand, clay, BD, Macro, GMD and WMD, and a negative correlation with silt, micro, TP. Based on the D values obtained, the ADE cultivated with cocoa showed superior quality in relation to the other areas studied.

Algumas áreas de Terra Preta Arqueológica na Amazônia vêm sendo utilizadas com pastagem o que tem gerado grande preocupação quanto às alterações dos atributos físicos e o estado de agregação do solo. O objetivo deste estudo foi avaliar a variabilidade espacial e as possíveis modificações dos atributos físicos e agregados do solo em terra preta arqueológica sob pastagem. Uma grade de 80 x 56m foi usada e a amostragem realizada em 88 pontos em disposição de 8 x 8m. Nas camadas de 0-0,05, 0,05-0,10 e 0,10-0,20m foram avaliados: a densidade do solo (Ds), carbono orgânico total (COT), estoque de carbono (Est C), diâmetro médio ponderado (DMP), macroporosidade (Macro), microporosidade (Micro) e volume total de poros (VTP). Pelo exame de semivariogramas constatou-se a ocorrência de dependência espacial. Mesmo a área de estudo sendo em pastagem observou-se que os valores de Ds, Macro e VTP, estiveram acima ou abaixo dos valores de referências que podem causar restrição ao crescimento radicular de plantas e à infiltração de água no solo. O DMP e Ds foram dependentes do COT, pois os valores de ambos aumentam ou diminuem de acordo com a camada. Com o aumento da camada do solo, houve o acréscimo do estoque de carbono.

The consumption of contaminated water is a major source of heavy metal contamination in humans and animals. This study therefore aimed to assess Cd, Cu, Mn, Ni, Pb, and Zn levels in water used for human and animal consumption and vegetable crop irrigation in Camocim de São Félix, Pernambuco, Brazil. Water samples were collected on the studied farms from an artesian well and reservoirs used for human and animal consumption as well as for crop irrigation. The results showed that concentrations of Cd (> 0.001 mg L-1), Ni (> 0.025 mg L-1) and Pb (> 0.01 mg L-1) were above the maximum allowable limits established under Brazilian law, indicating the need for a preventive monitoring program and immediate intervention initiatives aimed at the sources of contamination. The results demonstrate the need to quantify heavy metal content in vegetable crops, since their contamination by irrigation water may make them harmful to human health. Rainfall has a seasonal effect on heavy metal concentrations in water, showing a significant effect on Pb levels, whereas Cd and Ni content was less dependent on seasonal variation.

Para se avaliar a qualidade do solo e a sustentabilidade em ambientes de Terra Preta Arqueológica da Amazônia, é importante a caracterização dos impactos de uso de solo dos diferentes tipos de cobertura. Sendo assim, o objetivo deste trabalho foi avaliar os atributos físicos e o carbono orgânico em áreas de Terra Preta Arqueológica, no município de Novo Aripuanã, AM, sob os cultivos feijão guandu (Cajanus cajan) e pastagem, em comparação com a cobertura de floresta, com base em técnicas de estatística tradicional univariada e multivariada e de geoestatística. Para isso foram delimitadas malhas com espaçamentos regulares e 88 pontos amostrais georreferenciados por malha. Foram coletadas amostras em blocos de solo com estrutura preservada e anéis volumétricos, para a determinação das propriedades físicas e do carbono orgânico do solo. O feijão guandu e pastagem diferem estatisticamente da floresta, que apresentaram características de estabilidade dos agregados acima da média, mas características texturais e carbono orgânico abaixo da média. O modelo exponencial, pelo semivariograma escalonado, mostrou que atributos físicos do solo apresentaram predominância, com grau de dependência de forte a moderado, sendo a área sob feijão guandu com maior variabilidade dos atributos do solo.

The soil and vegetation characteristics of the southern Amazonas region include highly weathered soils, high aluminum content and some hydromorphic conditions, its vegetation is composed from grasslands to small isolated trees and forest galleries along the rivers streams. In this way, this work aims to characterize and classify the soil in areas of clean field, dirty field, and forest in Humaitá region AM. Soil trenches were opened in the clean field, dirty field, and forest environments, soil profiles were morphologically characterized, and samples were collected from their horizons. Physical analysis of texture, dispersed clay in water, flocculation, bulk density, particle density and porosity were performed. The chemical analyzes included pH and KCl in water; Ca, Mg, K, Al, and; available P; H+Al and organic C; SiO2, Al2O3 and Fe2O3 sulfuric attack. The soils were classified according to criteria established by the Brazilian System of Soil Classification and Soil Taxonomy. The forest, dirty field (high) and clean field (low) showed different soil types, Typic Dystrudept for the first two environments and Typic Fluvaquents for last. Multivariate techniques expressed the similarity relations presenting between the different environments studied, characterizing, which are of great importance in the relation landscape-soil studies.

Archeological Dark Earths (ADEs) are fertility soils that are notoriously superior to the vast majority of soils typical of the Amazon region. The study on ADEs has intensified due to the good characteristics presented by these soils, such as high concentration of nutrients (phosphorus, calcium, magnesium). In this sense, the aim of this study was to evaluate the spatial distribution of soil chemical attributes in an area of black archeological earth soil under cocoa cultivation in the municipality of Apuí (AM). The mapping of a 42 x 88 m mesh, with irregular spacing of 6 x 8 m, totaling 88 points, was carried out, and then soil samples were collected at depths of 0.0-0.05; 0.05-0.10; (pH, O.C, Sto C, (H+Al), P, K, Ca, Mg, SB, CEC and V%). Data were analyzed using descriptive and geostatistical statistics techniques. The mean and median values were adjusted to the near values, indicating normal distribution, while the soil chemical attributes were adjusted to the spherical and exponential semivariograms models. The majority of the attributes presented coefficient of variation (CV) between 12.1 and 60%, characterized as average variability, the variables in the study presented different ranges and most of them had a strong spatial dependence. The geostatistical techniques used allowed the adjustments of the theoretical models that best represented the experimental semivariance, thus enabling the construction of thematic maps of the spatial distribution of the values of the attributes of the studied area.

O sudoeste da Amazônia Brasileira é composto por um mosaico de paisagem com transição de campos naturais e floresta ombrófila densa. A bacia do rio Puruzinho, localizada no “Arco do Desmatamento” no interflúvio Purus-Madeira, tem passado por mudança no uso e cobertura da terra. Assim, o objetivo deste estudo foi avaliar a variação espacial de índices biofísicos de uma paisagem heterogênea na bacia hidrográfica do rio Puruzinho. O índice de vegetação da diferença normalizada (NDVI), índice de área foliar (IAF), temperatura da superfície, albedo e saldo de radiação da superfície (Rn) foram estimados pelo SEBAL (Surface Energy Balance Algorithm for Land) a partir de imagens TM Landsat 5, e analisados sobre floresta densa, campos naturais, área desmatada e área urbana de Humaitá-AM. Todos os índices biofísicos foram significativamente diferentes, considerando o uso e cobertura da terra. Os índices biofísicos apresentaram padrão inverso entre a área urbana e a floresta densa, com menor NDVI, IAF e saldo de radiação e maior temperatura e albedo da superfície na área urbana. Portanto, as variáveis estimadas pelo SEBAL foram adequadas para avaliar o efeito das mudanças no uso do solo sobre as variáveis estimadas e distinguir áreas antropizadas de áreas naturais.

The landscape configuration favors the understanding of the behavior of textural attributes being influenced to a lesser extent by the strand segments because the migration of sediments, water and nutrients meet the surface geological processes and to weathering. This study aim to characterize the spatial variability of texture in an irrigated area by center pivot in different positions in the landscape in the Crystalline, state GO region. Soil samples were taken at regular intervals of 10 m, shaped mesh, totaling 180 sampling points in different positions in the landscape. Samples were collected at depths of 0.00 to 0.10 m, 0.10-0.20 0.20-0.30 m me for the determination of clay, silt and sand. The data were submitted to descriptive statistics, geostatistics and kriging interpolation. The results demonstrate that migration occurred particles followed the flow of water present in causing the selective transport of sediment, which would imply higher erosion sediments, water and nutrients. The shed forms conditioned the movement and concentration of soil particles. The migration of clay to subsurface soil layers is related to the genesis of the soil and carrying of. = A configuração da paisagem favorece o entendimento do comportamento dos atributos texturais, sendo influenciada em menor escala pelos segmentos de vertente, pois a migração de sedimentos, água e nutrientes obedecem aos processos geológicos superficiais e ao intemperismo. Diante disso, objetivou-se com esse trabalho caracterizar a variabilidade espacial da textura em uma área irrigada por pivô central em diferentes posições na paisagem da região de Cristalina-GO. Foram realizadas amostragens do solo em intervalos regulares de 10 m, em forma de malha, totalizando 180 pontos, em diferentes posições da paisagem. As amostras foram coletadas s nas profundidades de 0,00-0,10 m, 0,10-0,20 m e 0,20-0,30 m para a determinação dos teores de argila, silte e areia. Os dados foram submetidos à análise estatística descritiva, geoestatística e interpolação por krigagem. Os resultados demonstram que a migração de partículas seguiu o fluxo de água na vertente causando o transporte seletivo de sedimento, o que implica em maior erosão de sedimentos, água e nutrientes. As formas da vertente condicionaram o movimento e a concentração das partículas do solo. A migração de argila para camadas subsuperficiais do solo é relacionada com a gênese do solo e ao carreamento de partículas pela água.

A dificuldade em encontrar informações recentes sobre o comportamento espacial dos atributos dos solos na Região Amazônica tem sido preocupação de muitos pesquisadores. Em razão da grande dificuldade e dos custos para avaliar os atributos dos solos, têm-se utilizados métodos alternativos para predição de atributos do solo como a suscetibilidade magnética. Sendo assim, o objetivo deste trabalho foi avaliar a variabilidade espacial da suscetibilidade magnética (SM), os atributos físicos e químicos e determinar a densidade amostral de coleta em Argissolo Vermelho sob floresta nativa, Terra Preta Arqueológica (TPA) sob cultivo, e pastagem na região de Manicoré, Amazonas. Nessas áreas, foram estabelecidas malhas com dimensão de 70 × 70 m e demarcados pontos nessas malhas, espaçados a cada 10 m, totalizando 64 pontos. Esses pontos foram georreferenciados e, em seguida, realizaram-se as coletas de solo em cada ponto da malha nas camadas de 0,00-0,20 e 0,40-0,60 m para determinar atributos químicos (pH em água, matéria orgânica, P, K, Ca, Mg e acidez potencial), físicos (textura, macroporosidade, microporosidade, diâmetro médio ponderado, densidade do solo e densidade de partículas) e suscetibilidade magnética. Os dados foram submetidos à análise de variância, e as médias, comparadas pelo teste de Tukey a 5 %. Realizou-se a estatística descritiva. Para caracterizar a variabilidade, fez-se a geoestatística com uso de semivariograma escalonado. O alcance dos semivariogramas escalonados foi utilizado para determinar a densidade amostral mínima de coleta para estimar a variabilidade dos atributos estudados. As áreas de TPA e pastagem apresentaram maior variabilidade, apresentando menor alcance e maior densidade amostral (cinco pontos por hectare). A SM apresentou comportamento espacial similar aos atributos físicos e químicos estudados, sendo a densidade amostral da SM próxima à densidade amostral dos atributos nos ambientes estudados.

There is a great lack of information from soil surveys in the southern part of the State of Amazonas, Brazil. The use of tools such as geostatistics may improve environmental planning, use and management. In this study, we aimed to use scaled semivariograms in sample design of soil physical properties of some environments in Amazonas. We selected five areas located in the south of the state of Amazonas, Brazil, with varied soil uses, such as forest, archaeological dark earth (ADE), pasture, sugarcane cropping, and agroforestry. Regular mesh grids were set up in these areas with 64 sample points spaced at 10 m from each other. At these points, we determined the particle size composition, soil resistance to penetration, moisture, soil bulk density and particle density, macroporosity, microporosity, total porosity, and aggregate stability in water at a depth of 0.00-0.20 m. Descriptive and geostatistical analyses were performed. The sample density requirements were lower in the pasture area but higher in the forest. We concluded that managed-environments had differences in their soil physical properties compared to the natural forest; notably, the soil in the ADE environment is physically improved in relation to the others. The physical properties evaluated showed a structure of spatial dependence with a slight variability of the forest compared to the others. The use of the range parameter of the semivariogram analysis proved to be effective in determining an ideal sample density.

Terras Pretas de Índio são solos de uma fertilidade notoriamente superior à grande maioria dos solos típicos da região Amazônica. Apresentam em sua composição fragmentos de cerâmica e artefatos indígenas incorporados a matriz dos horizontes superficiais, dispõem de alta estabilidade e persistência mantendo sua fertilidade mesmo depois de vários anos. Nesse sentido, o presente trabalho tem como objetivo avaliar a variabilidade espacial dos atributos químicos do solo em área de Terra Preta de Índio sob cultivo de feijão em Novo Aripuanã, AM. Foi realizado o mapeamento de uma malha de 20,0 x 72,0 m, com espaçamento regular de 5,0 x 4,0 m, nas profundidades de amostragem 0,0 - 0,05, 0,05 - 0,10 e 0,10 - 0,20 m, totalizando 90 pontos. Foram realizadas análises químicas como: pH em água, fósforo (P), concentração de alumínio (Al), e acidez potencial (H+Al). Os dados foram analisados utilizando-se técnicas estatísticas descritivas e de geoestatística. Os químicos estudados apresentaram estrutura de dependência espacial, com exceção da variável alumínio que indicou efeito pepita puro. Os valores de alcance foram diferentes variando de 8,73 a 81,00 m, estando dentro do limite estabelecido pela malha de estudo. Spatial variability of chemical atributes in cultivated archeological dark earth in Novo Aripuanã region Abstract: Archeological dark earth are soils of higher fertility than majority of typical soils from the Amazon region. These have in its composition, pottery fragments and indian artifacts embedded in the matrix of the surface horizons, present high stability and persistence, which maintains its fertility even after several years. The objective of the study was to evaluate the spatial variability of chemical atributes in archeological dark earth under bean cultivation, Novo Aripuanã, Amazonas. Was conducted mapping a mesh of 20.0 x 72.0 m, with regular spacing of 5.0 x 4.0 m, in the sampling depths from 0.0-0.05, 0.05-0.10 and 0.10-0.20 m, totaling 90 points. Were performed some chemical analyzes: pH, phosphorus (P), aluminum concentration (Al), and potential acidity (H + Al). Data were analyzed using descriptive statistics techniques and geostatistical. The studied chemical had spatial dependence structure, except for the aluminum that indicated pure nugget effect. The range values were different ranging from 8.73 to 81.00 m, and within the limits established by the mesh study. Terras Pretas de Índio são solos de uma fertilidade notoriamente superior à grande maioria dos solos típicos da região Amazônica.. São solos comApresentam em sua composição fragmentos de cerâmica e artefatos indígenas incorporados a matriz dos horizontes superficiais, do solo, apresentam dispõem de alta estabilidade e persistência mantendo sua fertilidade mesmo depois de vários anos. Nesse sentido, o presente trabalho tem como objetivo avaliar a variabilidade espacial dos atributos químicos do solo em área de Terra Preta de Índio sob cultivo de feijão em Novo ManicoréAripuanã, [B1] AM. Foi realizado o mapeamento de uma malha de 20,0x 72,0 m, com espaçamento regular de 05,0x 04,0 m, nas profundidades de amostragem 0,0-0,05, 0,05-0,10 e 0,10-0,20 m, totalizando 90 pontos. Foram realizadas análises químicas como: pH em água, fósforo (P), concentração de alumínio (Al), e acidez potencial (H+Al). Os dados foram analisados utilizando-se técnicas estatísticas descritivas e de geoestatística. Os químicos estudados apresentaram estrutura de dependência espacial, com exceção da variável alumínio que indicou efeito pepita puro. Os valores de alcance foram diferentes variando de 8,73 a 81,00 m, estando dentro do limite estabelecido pela malha de estudo. [B1]Num é em Novo Aripuanã não?

Natural grasslands with savannah-like characteristics associated to forest mosaics are found within Southern and Eastern Amazonas, Western Rondônia and Northern Roraima, being conditioned to local edaphic factors. The aim of this study was to assess both physical and geospatial attributes of an Cambisol under natural grasslands and an Ultisol under a forest fragment in Humaitá - AM, Brazil. In each area, we established a sampling grid in the dimensions of 70 × 70 m, with regular sampling spacing of 10 m and three collection depths: 0.0-0.05, 0.05-0.10 and 0.10-0.20 m, totaling 192 sampling points. Macroporosity (MaP), microporosity (MiP), bulk density (Ds) and total porosity (TP) were determined by soil samples with preserved structure, using a volumetric ring. Soil resistance to penetration (SRP) was measured by an automatic penetrometer after being subjected to a 0.006 MPa tension. Data were submitted to descriptive statistics and geostatistics analysis. The soil under natural grasslands showed values considered critical of Ds, SRP, MaP at all evaluated depths, with significant values at 0.10-0.20 m layer of 1.54 kg dm-3; 2.08 MPa and 0.05 m3 m-3, respectively. Ultisol under the forest fragments showed higher range values and consequently greater geospatial continuity due to the assessed physical attributes, since this soil has a greater stability of its physical structure. Based on the physical properties of the soil, structural function ineffectiveness of the Ultisol is a key factor for the occurrence of grassland in this region.