ABSTRACT Background: Chagas disease (CD) is caused by Trypanosoma cruzi and transmitted by triatomines. Historical information from the 20th century demonstrates T. cruzi records in the metropolitan region of Salvador (MRS), the third largest urban agglomeration in the Brazilian Northeast and the eighth largest in Brazil, an area with intense migratory activity from CD-endemic regions. Therefore, this study aimed to evaluate CD indicators (prevalence and mortality) in the MRS. Methods: A mixed ecological and descriptive study was conducted using secondary data. We analyzed data from 2008 to 2015: deaths due to CD, self-reported cases of CD, and blood donors that were non-negative for T. cruzi infection. Results: São Francisco do Conde was one of the municipalities with the highest mortality rates due to CD. The seroprevalence rates varied by year and municipality; those with the highest values were 2008: Vera Cruz, 2009: Mata de São João, 2010: Dias D'Ávila, 2011 and 2015: São Francisco do Conde, 2012: São Sebastião do Passé, and 2013 and 2014: Pojuca. Spatial correlations between the municipalities were not detected. Conclusions: We conclude that CD is present in the MRS. The indicators analyzed in the MRS are below-state-level data. Given the importance of indicator analysis for the surveillance and control of CD at the state and national levels, it is important to strengthen the surveillance program at the municipal level, including the regions classified as low risk for T. cruzi vector transmission.

ABSTRACT Amazonian soils have been suffering severe changes resulting from human activities in the region, causing significant changes in soil attributes that can contribute to greater susceptibility to erosion processes. Therefore, the present work aimed to estimate the erodibility in natural and anthropic environments in the southern region of the Amazon. Eight areas in the region were selected, including areas of native forest, savannah, cerradão, pasture and reforestation, delimiting 32 sampling points per area, with collections at a depth of 0.00-0.20 m, totaling 256 samples. Next, texture analysis and quantification of soil organic carbon were performed, and then erodibility was estimated by indirect prediction methods, Tukey’s test, Pearson’s correlation and factorial analysis of principal components. According to the results obtained, it was observed that the evaluated areas of native forest 1 and 2, cerradão and pasture present high susceptibility to erosion in relation to the cerrado, reforestation with genipap, teak and mixed areas. Therefore, it was noted that the high level of erodibility is associated with a greater predominance of sand fraction, K factor, Ki Kr and low clay content, as well as with the management employed in the areas.

Abstract The diversity of forest species is an intrinsic characteristic of the Amazon biome, with litter being the main responsible for the largest portion of nutrients returned to the soil. Thus, the objective of this study was to quantify the annual production of burlap and to determine the rate of decomposition over one year, comparing the results in the different study environments. The study was developed in the municipality of Humaitá-AM. For the evaluation of the litter production, ten cone collectors were randomly installed in each study area. Each litter sample was placed separately in properly identified paper bags and taken to the laboratory and dried in a forced air circulation oven at 65 ° C. The litter decomposition rate was estimated by mass loss analysis using litter bags. Litter production with the highest annual average was 8,03 Mg ha-1 year -1 for the native forest environment, with no significant difference for the other study areas. Among the fractions of the litter that contributed the most to the leaf, reaching a higher average percentage in the year of 72,1% for the environment of reforestation with teak (Tectona grandis L.). The decomposition of litter occurred more rapidly (0.0025 g g-1 day) in the reforestation environment with genipap (Genipa americana L.), requiring 277,26 days to decompose half of the leaf material.

Resumo A diversidade de espécies florestais é uma característica intrínseca do bioma Amazônico, sendo a serapilheira a principal responsável pela maior parcela dos nutrientes devolvidos ao solo. Dessa forma, o objetivo deste estudo foi quantificar a produção anual de serapilheira e determinar a velocidade de decomposição ao longo de um ano, comparando os resultados nos diferentes ambientes de estudo. O estudo foi desenvolvido no município de Humaitá-AM. Para a avaliação da produção de serapilheira, foram instalados de modo aleatório dez coletores cônicos em área de Floresta Nativa, área de Reflorestamento com Teca (Tectona grandis L), área de Reflorestamento com Jenipapo (Genipa americana L.) e ambiente de Reflorestamento considerado Misto, composto pelas espécies Mogno (Swietenia macrophylla King.), Andiroba (Carapa guianensis Aubl.), Jenipapo (Genipa americana L.), Teca (Tectona grandis L.) e Sumauma (Ceiba pentandra). Cada amostra de serapilheira foi colocada, separadamente, em sacos de papel devidamente identificados e levadas para laboratório e secas em estufa de circulação de ar forçado a 65°C. A estimativa da taxa de decomposição da serapilheira foi feita pela análise de perda de massa utilizando-se litter bags. A produção de serapilheira média anual foi de 8,03 Mg ha-1 ano-1 para o ambiente de floresta nativa, e não houve diferença significativa para as demais áreas de estudo. Entre as frações da serapilheira, a que mais contribuiu foi a foliar, atingindo maior média percentual no ano de 72,1% para o ambiente de reflorestamento com teca (Tectona grandis L.). A decomposição da serapilheira ocorreu de forma mais acelerada (0,0025 g g-1dia) no ambiente de reflorestamento com jenipapo (Genipa americana L.), sendo necessários 277,26 dias para que fosse decomposta metade do material foliar.

RESUMO Os solos da região amazônica, apesar de estarem sob uma das florestas mais densas do mundo, são caracterizados, na sua maioria, pela baixa disponibilidade de nutrientes, sendo a serapilheira a principal via de entrada de nutrientes. O objetivo desse estudo foi quantificar a biomassa de raízes finas na época seca e chuvosa do ano, incluindo o carbono orgânico do solo, e comparar os resultados nos diferentes ambientes de estudo. O estudo foi desenvolvido em ambientes de floresta nativa e reflorestamento com idade acima de 20 anos, localizado no município de Humaitá- AM. Para avaliação da biomassa de raízes, foram realizadas coletas em dois períodos do ano: seco e chuvoso. Em cada uma das áreas de estudo foram escavadas manualmente cinco trincheiras, com dimensão de 0,40 m de profundidade por 0,40 m de largura, nas profundidades de 0-5, 5-15 e 15-30 cm. Para análise de carbono orgânico foram coletadas amostras de solo em forma de torrão nas mesmas profundidades. A produção de biomassa radicular no ambiente de floresta nativa ocorreu de forma mais intensa no período chuvoso, chegando a valores de 8,19 t. ha-1, superior a 3,57 t. ha-1 encontrado em reflorestamento. A densidade em função do volume de solo mostrou que a maior concentração se encontra nos primeiros 5 centímetros de profundidade, diferenciando significativamente nas camadas de 5-15 e 15-30 cm para área de floresta nativa. O carbono orgânico do solo apresentou significância entre o período seco e chuvoso para os ambientes de floresta natural e reflorestamento com jenipapo.

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.

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.

Resumo A erodibilidade é uma característica do solo que representa a susceptibilidade com que suas partículas da camada mais superficial são levadas e transportadas para locais mais baixos por agentes erosivos, causando danos ambientais e econômicos. O objetivo deste trabalho foi estimar a erodibilidade do solo em áreas de pastagens e florestas no município de Porto Velho-Rondônia. Em campo, foram selecionadas três áreas com diferentes tipos de vegetação, uma com braquiária, outra com capim mombaça e uma terceira em floresta nativa. Nas áreas com pastagens, foi delineada uma malha amostral de tamanhos iguais (90 m x 60 m), e na área de floresta uma malha amostral aproximada (90 m x 50 m), com espaçamento regular de 10 m entre os pontos amostrais para ambas as áreas. A amostragem foi realizada nos pontos de cruzamento da malha na profundidade de 0,0-0,2 m, compondo 70 pontos amostrais nas áreas com pastagens e 60 pontos amostrais na área de floresta, totalizando 200 amostras. Em seguida, foram realizadas análises laboratoriais para determinação da textura seguida do fracionamento da areia, e do carbono orgânico seguida da estimativa da matéria orgânica do solo. Os fatores de erodibilidade foram calculados por meio de modelos de predição indireta e, em seguida, foram aplicadas técnicas univariadas, geoestatísticas e multivariadas. Os ambientes de pastagem diferiram do ambiente de floresta. No entanto, a área de capim mombaça funciona como um ambiente intermediário entre a floresta e a braquiária, estando mais próxima do ambiente de floresta.

Abstract “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.

ABSTRACT In the Amazon region, soil patches with an anthropic A horizon are found, called Indian black earths (IBEs). Indian black earths are highly fertile and, therefore, are deforested by small local farmers to cultivate without basic management that maintains soil and crop sustainability. Therefore, in order to evaluate the effect of using different cultures on the spatial variability of soil chemical attributes, three cultivated IBEs and one IBE under natural forest were selected for georeferencing and sample collection. The collection was made with a mesh system with 88 points per IBE, stratified in three layers: 0–0.05, 0.05–0.10 and 0.10–0.20 m. The soil was sampled, dried in the shade and sieved to obtain the fine earth fraction for analysis of chemical attributes. Descriptive statistical and geostatistical analyses were applied to the results. The use and management of soil influenced the spatial behavior of the chemical attributes of IBEs. The cultivation of Brachiaria over many years favored the reduction of the spatial variability of chemical attributes. The use of cacao and coffee crops also favored the homogeneity of the IBEs in relation to the natural forest, but not as much as for Brachiaria, likely due to the succession of crops that preceded these crops. The IBE in the forest contains a high natural spatial correlation in the first 0.1 m of the surface; however, more than 70% of this correlation is linked to a random variation.

ABSTRACT The objective of this work was to evaluate soil attributes and root distribution in areas under forest conversion to cultivated environments. The study was carried out in four areas: forest, cupuaçu, guarana and annatto, located in the municipality of Canutama, state of Amazonas. Soils and volumetric rings were collected in the layers 0.00 – 0.10; 0.10 – 0.20; 0.20 – 0.30; 0.30 – 0.40; and 0.40 – 0.50 m for analyses of physical and chemical attributes and root distribution. Univariate statistical analyses were carried out, the means were compared with the Tukey’s test (p < 0.05) and Pearson’s correlation (p < 0.05 and < 0.01). The forest area and the cultivated environments present soil chemical limitations for agricultural production, whereas the physical attributes presented satisfactory values. The chemical attributes underwent major changes and degradations upon conversion to agriculture. Major changes were observed in the layers of 0.00 – 0.10 and 0.10 – 0.20 m for the studied areas. Cupuaçu cultivation showed higher values of roots dry weight (RDW) and roots distribution (RD), with the highest values found in the 0.00 – 0.10 and 0.10 – 0.20 m layers.

Resumo O reconhecimento da influência das práticas de manejo nas condições físicas e químicas do solo é substancial para a agricultura sustentável. Por essa razão, o estudo foi desenvolvido com o objetivo de avaliar o comportamento de atributos do solo sob diferentes usos na região de Humaitá, AM, utilizando métodos estatísticos multivariados. O estudo foi desenvolvido em 8 propriedades rurais produtoras de banana, pastagem, milho, café, mandioca, hortaliças, sistema agroflorestal e fragmento florestal. Amostras de solos com estrutura preservada nas camadas de 0,0 - 0,10 e 0,10 - 0,20 m foram coletadas aleatoriamente em 5 pequenas trincheiras por área, totalizando 32 amostras nos sistemas de manejo, para determinar os atributos físicos e químicos. Os dados foram então submetidos à análise estatística univariada e multivariada. Análises exploratórias de dados (componentes principais e dendrogramas) e frequência de covariáveis ambientais foram eficientes em distinguir ambientes de produção, portanto a classificação multivariada baseada em atributos físicos e químicos do solo pode auxiliar no planejamento adequado do uso da terra. A análise dos componentes principais indica que a DS apresenta dependência direta com o RSP, sinalizando o uso do solo com pastagem o único no processo de compactação. A acidez do solo é o principal fator limitante para o desenvolvimento da cultura, exigindo a adoção de práticas corretivas de pH do solo com melhorias na oferta de nutrientes. A conversão da floresta para pastagem manteve a característica estrutural do solo, enquanto os demais usos incrementaram melhorias na qualidade física e fertilidade do solo.

Abstract 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.

Resumo O consumo de águas contaminadas representa uma das principais vias de contaminação humana e animal por metais pesados. Neste sentido, o objetivo deste trabalho foi determinar as concentrações de Cd, Cu, Mn, Ni, Pb e Zn em águas utilizadas para consumo humano e animal e na irrigação de hortaliças no município de Camocim de São Félix (PE). Nas propriedades agrícolas, as amostras de água analisadas foram coletadas de poço artesiano e de reservatórios destinados ao consumo humano, animal e irrigação das lavouras. Os resultados demonstraram que as águas analisadas no presente estudo apresentaram concentrações de Cd (> 0,001 mg L-1), Ni (> 0,025 mg L-1) e Pb (> 0,01 mg L-1) superiores aos teores máximos permitidos indicados pela legislação brasileira, sinalizando a necessidade de um programa de monitoramento preventivo e ações de intervenção imediata das fontes de contaminação. Os resultados indicam a necessidade de quantificação das concentrações de metais pesados nas hortaliças, visto que contaminadas pelas águas de irrigação podem ser uma fonte nociva à saúde humana. A precipitação pluviométrica tem influência sobre a variação sazonal dos teores dos metais nas águas, com maior efeito na concentração de Pb e influência moderada nas concentrações de Cd e Ni.

Abstract 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.

Resumo 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.

Abstract Some areas of archaeological dark dirt in the Amazon have been used with pasture that has generated great concern regarding changes in soil physical attributes and its aggregation state. The objective of this study was to evaluate the spatial variability and possible modifications of soil physical and aggregate attributes in archaeological black dirt under pasture. A grid of 80 x 56m with 88 sampling points distributed in 8 x 8m were marked. Soil layers at 0-0.05, 0.05-0.10, and 0.10-0.20m were analyzed for: soil density (SD), total organic carbon (TOC), carbon stock (C stock), meanweight diameter (MWD), macroporosity (Macro), microporosity (Micro), and total porosity (TP). From semivariograms tests it was verified the occurrence of spatial dependence. Even with major pasture cover in the study area it was observed that the values of Ds, Macro, and VTP were above or below the reference values, which may cause restriction for root growth of plants and water infiltration in the soil. The DMP and Ds were COT-dependent because values of both increase or decrease depending on the soil layer. When higher the soil layer there was an increase in carbon stock.

Resumo 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.

Abstract In order to evaluate soil quality and sustainability in Amazon Archaeological Dark Earth environments, it is important to characterize the impacts of the use of different cover types. The objective of this work was therefore to evaluate the physical attributes and organic carbon content in areas of “Terra Preta Arqueológica”, in the municipality of Novo Aripuanã, AM, under the cultivation of pigeon pea (Cajanus cajan) and pasture, in comparison with forest cover, based on traditional univariate and multivariate statistical techniques and geostatistics. In order to accomplish this, grids with regular spacing and samples with 88 georeferenced points per grid were delimited. Samples of soil blocks with preserved structure and volumetric rings were collected to determine physical properties and organic carbon content. The pigeon pea and pasture soils differ statistically from that of the forest and presented above-average aggregate stability, but texture and organic carbon characteristics were below average. The exponential model showed that the physical attributes of the soil predominated, with a strong to moderate degree of dependence, with the area under pigeon pea presenting the greatest variability of soil attributes.

RESUMO: Atualmente compreender os fatores que influenciam as emissões de CO2 em ambientes amazônicos vem sendo discutidos com mais intensidade, devido o acelerado aumento nas variações climáticas (temperatura e precipitação) as quais influenciam nas trocas entre os ecossistemas terrestres e a atmosfera. Diante do exposto, o objetivo deste trabalho foi avaliar a distribuição espacial da emissão de CO2 e atributos do solo sob campo nativo na região de Humaitá, Amazonas. Foi delimitada uma malha amostral de 70 m x 70 m com 64 pontos regularmente espaçados a uma distância de 10 m e georreferenciados. Amostras de solos foram coletadas em cada ponto da malha nas camadas de 0,00-0,05 m e 0,05-0,10 m, para determinação dos atributos físicos do solo e do carbono orgânico, totalizando 128 amostras de solo. Nos pontos de cruzamento da manha foram avaliadas a emissão de CO2, a temperatura e a umidade do solo, utilizando o sistema LI-6400. As emissões de CO2 na área de campo nativo nas condições do presente estudo são fenômenos de natureza complexa, não sendo possível identificar um único atributo do solo ou do ambiente que explique sua variação no espaço, indicando assim que uma dificuldade ao estabelecer relações entre os atributos do solo e emissão de CO2 ocorre devido à complexidade do fenômeno.

ABSTRACT: Currently understand the factors that influence the emissions of CO2 in the Amazonian environment has been discussed more intensively, because the rapid increase in climatic variations (temperature and precipitation) which influence the exchanges between terrestrial ecosystems and the atmosphere. Given the above, the objective of this study was to evaluate the spatial distribution of CO2 emissions and soil properties under native pasture in Humaitá region, Amazonas. A sampling grid of 70 m x 70 m with 64 points regularly spaced at a distance of 10 m and georeferenced was delimited. Soil samples were collected at each grid point in layers of 0.00 to 0.05 m and 0.05-0.10 m for determination of soil physical properties and organic carbon, 128 soil samples. At the crossing points in the morning they were evaluated CO2, temperature and soil moisture, using the LI-6400 system. CO2 emissions in native pasture area in the present study conditions are complex nature of phenomena, it is not possible to identify a single soil attribute or the environment to explain the variation in space, thus indicating that a difficulty in establishing relationships between attributes soil and CO2 emission is due to the complexity of the phenomenon.

RESUMO Mudanças no uso do solo têm motivado pesquisas sobre a dinâmica de trocas radiativas e energéticas na Amazônia Brasileira que, por sua vez, geram demanda destas informações de superfície em escalas espaciais e temporais. Enquanto a medição destas trocas em torres micrometeorológicas fornece resultados pontuais, o sensoriamento remoto apresenta resultados acurados e de baixo custo para estimá-las em escala regional. Este estudo objetivou avaliar a distribuição espacial e temporal de estimativas de saldo de radiação e parâmetros biofísicos por sensoriamento remoto de diferentes usos do solo no sudoeste da Amazônia Brasileira. Foram selecionadas 04 áreas de solo coberto por floresta amazônica natural, floresta amazônica manejada, sistema silvipastoril e pastagem. O saldo de radiação, NDVI, índice de área foliar, albedo e temperatura radiométrica foram estimados pelo algoritmo SEBAL, usando imagens do sensor TM do satélite Landsat 5 em julho de 2009, 2010 e 2011. O NDVI, IAF, albedo e saldo de radiação apresentaram maiores valores na floresta natural, seguida por floresta manejada, sistema silvipastoril e pastagem. A temperatura radiométrica da superfície apresentou maiores valores para o sistema silvipastoril seguido por pastagem, floresta natural e floresta manejada.

ABSTRACT Changes in land use have motivated research on the dynamics of radiative and energy exchange in the Brazilian Amazon, which in turn cause demand for such data on the surface in spatial and temporal scales. While measuring these changes in micrometeorological towers provides punctual results, remote sensing provides accurate and low cost results to estimate them on a regional scale. This study aimed to evaluate the spatial and temporal distribution of estimates of net radiation and biophysical parameters from remote sensing in different land uses in southwestern Brazilian Amazon. Four sites were selected with soil covers by natural Amazon forest, Amazon managed forest, pasture and silvopastoral system. The net radiation and biophysical parameters (NDVI, leaf area index, albedo and radiometric temperature) were estimated by the SEBAL algorithm, using images from the Landsat TM sensor 5 in July of 2009, 2010 and 2011. The NDVI, LAI, albedo and net radiation were higher in natural forest, followed by managed forest, grassland and silvopastoral system. Radiometric surface temperature were higher in the silvopastoral system followed by pasture, natural forest and managed forest.

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 southwest area of the Brazilian Amazon is composed of a landscape mosaic with transition grasslands and tropical rain forest. The basin of the Puruzinho River, located in the "Arc of Deforestation" in the Purus-Madeira interfluve, has undergone changes in land use and land cover. The objective of this study was to evaluate the spatial variation of biophysical indices of a heterogeneous landscape in the Basin of Puruzinho River. The normalized difference vegetation index (NDVI), leaf area index (LAI), surface temperature, surface albedo and surface net radiation (Rn) were estimated by SEBAL (Surface Energy Balance Algorithm for Land) from TM Landsat 5 images, and analyzed on areas of dense forest, grasslands, deforested area and urban area of Humaitá-AM. All biophysical indices were significantly different considering the land use and land cover. The biophysical indices showed an opposite pattern between the urban area and the dense forest, with lower NDVI, IAF and net radiation and higher surface temperature and surface albedo in the urban area. Therefore, the variables estimated by SEBAL were adequate to assess the effect of land use changes on the estimated variables and to distinguish disturbed areas from natural areas.