Made available in DSpace on 2016-02-26T12:59:42Z (GMT). No. of bitstreams: 1 CarmemPezarico.pdf: 1886194 bytes, checksum: e2ce5573ff432d115a2b368c25c8a372 (MD5) Previous issue date: 2009-07-31 / The utilization of agroforestry systems to enable food production possible, providing improvement in the aspects that deal with the conservation of natural resources is nowadays considered a possible and effective alternative to guarantee the sustainability of the environmental, economic and social aspects. Therefore, it objectified to evaluate physical, chemical and microbiological attributes in different agroforestry management systems compared to other production systems. The assignment has been done in the property Sitio da Mata, situated in the municipality of Amambai, MS. Two distinct agro forestry systems were evaluated, being described as SAF A and SAF B, compared to a crop area, a silvicultural system with exploration of mate herb (Herbal) and a yardstick area of natural vegetation. The design was entirely randomized, being the treatments represented by the five systems and with five repetitions. The chemical attribute evaluated was organic matter. The physical attributes identified were soil density, macroporosity, microporosity, total volume of pores (TVP) and texture. The microbiological attributes studied were microbial biomass carbon (MBC), microbial activity (C-CO²) organic carbon, microbial and metabolic quotient (qCO²). Among the evaluated systems, SAF A was the one which presented the closest indices compared to the native vegetation, which implies the claim that the diversity of species as well as the most clayey type of soil provided better results in this system. The quickness of answer that some species such as green manure (dwarf pigeon pea, crotalaria spectabilis) and grasses, like the Napier grass (Pennisetum purpureum Schum.) have in the improvement of the chemical, physical and biological soil conditions, may explain some relations observed in the SAF A and with less intensity in the SAF B and herbal. The crop area was indicated as the most affected environment in the evaluated conditions. It was possible to indentify that the agroforestry systems are conservational systems from the soil quality perspective / A utilização de sistemas agroflorestais para viabilizar a produção de alimentos, proporcionando melhoria nos aspectos voltados para conservação dos recursos naturais é atualmente considerada uma alternativa possível e eficaz para garantir a sustentabilidade, tanto nos aspectos ambientais como econômicos e sociais. Nesse sentido, objetivou-se avaliar atributos físicos, microbiológicos e matéria orgânica em diferentes sistemas de manejo agroflorestais, comparados a outros sistemas de produção. O estudo foi realizado na propriedade denominada Sítio da Mata, localizado no Município de Amambai, MS. Foram avaliados dois Sistemas Agroflorestais (SAFs), sendo descritos como SAF A e SAF B, comparados a uma área de lavoura, um sistema silvicultural com exploração de ervamate (Erval) e uma área como referência da condição original do solo (vegetação natural-Mata). O delineamento utilizado foi inteiramente casualizado, sendo os tratamentos representados pelos cinco sistemas com cinco repetições. O atributo químico avaliado foi conteúdo de matéria orgânica. Os atributos físicos estudados foram densidade do solo, macroporosidade, microporosidade volume total de poros (VTP) e textura. Os atributos microbiológicos estudados foram carbono da biomassa microbiana (CBMS), atividade microbiana (C-CO2), carbono orgânico (Corg), quociente metabólico (qCO2) e quociente microbiano (Cmic/Corg). Dentre os sistemas avaliados, o SAF A foi o que apresentou os índices de qualidade do solo mais próximos comparados à área de vegetação nativa (mata), o que implica afirmar que a diversificação das espécies, como também o tipo de solo mais argiloso, promoveram melhores resultados neste sistema. A rapidez de resposta que algumas espécies utilizadas como adubos verdes (feijão, guandu e crotalaria) e gramíneas, como o napier, apresentaram melhoria das condições, químicas, físicas e biológicas do solo, podem explicar algumas relações observadas no SAF A e com menos intensidade no SAF B e erval. A área de lavoura indicou ser o ambiente mais afetado nas condições avaliadas, sendo possível identificar que os sistemas agroflorestais são sistemas mais conservacionistas sob o ponto de vista da sustentabilidade ambiental

Made available in DSpace on 2016-02-26T12:59:22Z (GMT). No. of bitstreams: 1 CarmemPezarico.pdf: 1886194 bytes, checksum: e2ce5573ff432d115a2b368c25c8a372 (MD5) Previous issue date: 2009-07-31 / The utilization of agroforestry systems to enable food production possible, providing improvement in the aspects that deal with the conservation of natural resources is nowadays considered a possible and effective alternative to guarantee the sustainability of the environmental, economic and social aspects. Therefore, it objectified to evaluate physical, chemical and microbiological attributes in different agroforestry management systems compared to other production systems. The assignment has been done in the property Sitio da Mata, situated in the municipality of Amambai, MS. Two distinct agro forestry systems were evaluated, being described as SAF A and SAF B, compared to a crop area, a silvicultural system with exploration of mate herb (Herbal) and a yardstick area of natural vegetation. The design was entirely randomized, being the treatments represented by the five systems and with five repetitions. The chemical attribute evaluated was organic matter. The physical attributes identified were soil density, macroporosity, microporosity, total volume of pores (TVP) and texture. The microbiological attributes studied were microbial biomass carbon (MBC), microbial activity (C-CO²) organic carbon, microbial and metabolic quotient (qCO²). Among the evaluated systems, SAF A was the one which presented the closest indices compared to the native vegetation, which implies the claim that the diversity of species as well as the most clayey type of soil provided better results in this system. The quickness of answer that some species such as green manure (dwarf pigeon pea, crotalaria spectabilis) and grasses, like the Napier grass (Pennisetum purpureum Schum.) have in the improvement of the chemical, physical and biological soil conditions, may explain some relations observed in the SAF A and with less intensity in the SAF B and herbal. The crop area was indicated as the most affected environment in the evaluated conditions. It was possible to indentify that the agroforestry systems are conservational systems from the soil quality perspective / A utilização de sistemas agroflorestais para viabilizar a produção de alimentos, proporcionando melhoria nos aspectos voltados para conservação dos recursos naturais é atualmente considerada uma alternativa possível e eficaz para garantir a sustentabilidade, tanto nos aspectos ambientais como econômicos e sociais. Nesse sentido, objetivou-se avaliar atributos físicos, microbiológicos e matéria orgânica em diferentes sistemas de manejo agroflorestais, comparados a outros sistemas de produção. O estudo foi realizado na propriedade denominada Sítio da Mata, localizado no Município de Amambai, MS. Foram avaliados dois Sistemas Agroflorestais (SAFs), sendo descritos como SAF A e SAF B, comparados a uma área de lavoura, um sistema silvicultural com exploração de ervamate (Erval) e uma área como referência da condição original do solo (vegetação natural-Mata). O delineamento utilizado foi inteiramente casualizado, sendo os tratamentos representados pelos cinco sistemas com cinco repetições. O atributo químico avaliado foi conteúdo de matéria orgânica. Os atributos físicos estudados foram densidade do solo, macroporosidade, microporosidade volume total de poros (VTP) e textura. Os atributos microbiológicos estudados foram carbono da biomassa microbiana (CBMS), atividade microbiana (C-CO2), carbono orgânico (Corg), quociente metabólico (qCO2) e quociente microbiano (Cmic/Corg). Dentre os sistemas avaliados, o SAF A foi o que apresentou os índices de qualidade do solo mais próximos comparados à área de vegetação nativa (mata), o que implica afirmar que a diversificação das espécies, como também o tipo de solo mais argiloso, promoveram melhores resultados neste sistema. A rapidez de resposta que algumas espécies utilizadas como adubos verdes (feijão, guandu e crotalaria) e gramíneas, como o napier, apresentaram melhoria das condições, químicas, físicas e biológicas do solo, podem explicar algumas relações observadas no SAF A e com menos intensidade no SAF B e erval. A área de lavoura indicou ser o ambiente mais afetado nas condições avaliadas, sendo possível identificar que os sistemas agroflorestais são sistemas mais conservacionistas sob o ponto de vista da sustentabilidade ambiental

Landscape position and depth in the soil column influence the movement of microbial substrate throughout a catchment, from upslope areas to downslope areas, thereby impacting nutrient cycling rates and capabilities of the microbial communities in those areas. Wildfire also shapes the biogeochemistry of the landscape, creating a mosaic with variations in substrate type and concentration that also influence microbial communities and biogeochemical cycling. Nitrogen (N) in particular is altered by wildfire, as it is easily volatilized and the removal of organic matter (OM) reduces N inputs. We aimed to understand how landscape position and soil depth, first and foremost, influence microbial communities and their N-cycling, but also how this may differ from wildfires and their relative impacts on the soil microbial communities. Landscape position proved to influence few soil and microbial characteristics, while movement from soil surface to deep in the column and the incidence of wildfire caused many variations in soil physical and biogeochemical cycling properties. The interaction of landscape position and soil depth also showed little variation in any measurements, while wildfire and soil depth interactions showed drastic changes that indicate high order controls over the soil microbial community. It can be surmised that while landscape position is important for many soil properties, it is soil depth and wildfire that truly control the soil microbial communities and their N-cycling capabilities.

Made available in DSpace on 2016-01-26T18:56:22Z (GMT). No. of bitstreams: 1 Giovana_Posdefesa 01_10_corrigido.pdf: 983760 bytes, checksum: 074cf78bd206957da41bcdea59101dc5 (MD5) Previous issue date: 2010-09-03 / The fertility and microbial activity in soil have been often used to indicate changes in soil quality. The microbial activity directly interacts with environmental conditions, soil types and different agricultural production systems used. Despite advances in this area, it is still a great challenge to define good indicators of soil quality, their interactions and behavior over time. Thus, the aim of this study was to assess the current state of soils under pastures in the western region of São Paulo using the evaluation and correlation of the microbial attributes and soil fertility. We performed on 108 soil samples, collected in settled pastures, analysis of thirteen variables in a laboratory within the microbial attributes, fertility and soil texture. The findings of the evaluation of the microbial demonstrated that microbial biomass had the lowest coefficient of variation, normal distribution of frequency and significantly correlated with most variables analyzed, on the other side, within the attributes of fertility of the soil, pH had the lowest rate variation while the phosphorus content demonstrated large variations with disproportionately high frequency among other variables, indicating the current status of soil degradation. The soil microbial biomass can be considered a good indicator for microbiological evaluation in these soils. The principal component analysis demonstrated that 51% of the variation was concentrated in the axis 1 and 2, which is considered representative for multivariate environmental assessment / A fertilidade e a atividade microbiana em solo têm sido utilizadas com frequencia para indicar mudanças na qualidade do solo. A atividade microbiana interage diretamente com as condições ambientais, classes de solo e diferentes sistemas de produção agrícola utilizados. Apesar dos avanços nesta área ainda é um grande desafio a definição de bons indicadores de qualidade do solo, suas interações e comportamento ao longo do tempo. Desta forma, o objetivo desse estudo foi verificar o estado atual de solos sob pastagens na região oeste paulista utilizando-se da avaliação e correlação de atributos microbiológicos e de fertilidade do solo. Foram realizadas em 108 amostras de solos, coletadas em áreas de pastagens estabelecidas, análises de treze variáveis em laboratório, dentro dos atributos microbiológicos, de fertilidade e granulométrico do solo. Os resultados encontrados na avaliação dos atributos microbiológicos demonstraram que a biomassa microbiana apresentou o menor coeficiente de variação, distribuição normal de freqüência e correlação significativa com a maioria das variáveis analisadas, por outro lado dentro dos atributos de fertilidade do solo o pH apresentou o menor coeficiente de variação enquanto que o teor fósforo apresentou grande variação com freqüência desproporcional indicando junto com outras variáveis o estado atual de degradação do solo. A biomassa microbiana do solo pode ser considerada como bom indicador para avaliação microbiológica nestes solos. A análise de componentes principais apresentou que 51% da variação concentrou-se dentro do eixo 1 e 2 o que é considerado representativa para avaliação ambiental multivariada

Made available in DSpace on 2016-07-18T17:51:06Z (GMT). No. of bitstreams: 1 Giovana_Posdefesa 01_10_corrigido.pdf: 983760 bytes, checksum: 074cf78bd206957da41bcdea59101dc5 (MD5) Previous issue date: 2010-09-03 / The fertility and microbial activity in soil have been often used to indicate changes in soil quality. The microbial activity directly interacts with environmental conditions, soil types and different agricultural production systems used. Despite advances in this area, it is still a great challenge to define good indicators of soil quality, their interactions and behavior over time. Thus, the aim of this study was to assess the current state of soils under pastures in the western region of São Paulo using the evaluation and correlation of the microbial attributes and soil fertility. We performed on 108 soil samples, collected in settled pastures, analysis of thirteen variables in a laboratory within the microbial attributes, fertility and soil texture. The findings of the evaluation of the microbial demonstrated that microbial biomass had the lowest coefficient of variation, normal distribution of frequency and significantly correlated with most variables analyzed, on the other side, within the attributes of fertility of the soil, pH had the lowest rate variation while the phosphorus content demonstrated large variations with disproportionately high frequency among other variables, indicating the current status of soil degradation. The soil microbial biomass can be considered a good indicator for microbiological evaluation in these soils. The principal component analysis demonstrated that 51% of the variation was concentrated in the axis 1 and 2, which is considered representative for multivariate environmental assessment / A fertilidade e a atividade microbiana em solo têm sido utilizadas com frequencia para indicar mudanças na qualidade do solo. A atividade microbiana interage diretamente com as condições ambientais, classes de solo e diferentes sistemas de produção agrícola utilizados. Apesar dos avanços nesta área ainda é um grande desafio a definição de bons indicadores de qualidade do solo, suas interações e comportamento ao longo do tempo. Desta forma, o objetivo desse estudo foi verificar o estado atual de solos sob pastagens na região oeste paulista utilizando-se da avaliação e correlação de atributos microbiológicos e de fertilidade do solo. Foram realizadas em 108 amostras de solos, coletadas em áreas de pastagens estabelecidas, análises de treze variáveis em laboratório, dentro dos atributos microbiológicos, de fertilidade e granulométrico do solo. Os resultados encontrados na avaliação dos atributos microbiológicos demonstraram que a biomassa microbiana apresentou o menor coeficiente de variação, distribuição normal de freqüência e correlação significativa com a maioria das variáveis analisadas, por outro lado dentro dos atributos de fertilidade do solo o pH apresentou o menor coeficiente de variação enquanto que o teor fósforo apresentou grande variação com freqüência desproporcional indicando junto com outras variáveis o estado atual de degradação do solo. A biomassa microbiana do solo pode ser considerada como bom indicador para avaliação microbiológica nestes solos. A análise de componentes principais apresentou que 51% da variação concentrou-se dentro do eixo 1 e 2 o que é considerado representativa para avaliação ambiental multivariada

abstract: Soil organic carbon (SOC) is a critical component of the global carbon (C) cycle, accounting for more C than the biotic and atmospheric pools combined. Microbes play an important role in soil C cycling, with abiotic conditions such as soil moisture and temperature governing microbial activity and subsequent soil C processes. Predictions for future climate include warmer temperatures and altered precipitation regimes, suggesting impacts on future soil C cycling. However, it is uncertain how soil microbial communities and subsequent soil organic carbon pools will respond to these changes, particularly in dryland ecosystems. A knowledge gap exists in soil microbial community responses to short- versus long-term precipitation alteration in dryland systems. Assessing soil C cycle processes and microbial community responses under current and altered precipitation patterns will aid in understanding how C pools and cycling might be altered by climate change. This study investigates how soil microbial communities are influenced by established climate regimes and extreme changes in short-term precipitation patterns across a 1000 m elevation gradient in northern Arizona, where precipitation increases with elevation. Precipitation was manipulated (50% addition and 50% exclusion of ambient rainfall) for two summer rainy seasons at five sites across the elevation gradient. In situ and ex situ soil CO2 flux, microbial biomass C, extracellular enzyme activity, and SOC were measured in precipitation treatments in all sites. Soil CO2 flux, microbial biomass C, extracellular enzyme activity, and SOC were highest at the three highest elevation sites compared to the two lowest elevation sites. Within sites, precipitation treatments did not change microbial biomass C, extracellular enzyme activity, and SOC. Soil CO2 flux was greater under precipitation addition treatments than exclusion treatments at both the highest elevation site and second lowest elevation site. Ex situ respiration differed among the precipitation treatments only at the lowest elevation site, where respiration was enhanced in the precipitation addition plots. These results suggest soil C cycling will respond to long-term changes in precipitation, but pools and fluxes of carbon will likely show site-specific sensitivities to short-term precipitation patterns that are also expected with climate change. / Dissertation/Thesis / Masters Thesis Biology 2019

Global urbanization has resulted in rapidly increased urban land. Soils are the foundation that supports plant growth and human activities in urban areas. Furthermore, urban soils have potential to provide a carbon sink to mitigate greenhouse gas emission and climate change. However, typical urban land development practices including vegetation clearing, topsoil removal, stockpiling, compaction, grading and building result in degraded soils. In this work, we evaluated an urban soil rehabilitation technique that includes compost incorporation to a 60-cm depth via deep tillage followed by more typical topsoil replacement. Our objectives were to assess the change in soil physical characteristics, soil carbon sequestration, greenhouse gas emissions, and stormwater mitigation after both typical urban land development practices and post-development rehabilitation. We found typical urban land development practices altered soil properties dramatically including increasing bulk density, decreasing aggregation and decreasing soil permeability. In the surface soils, construction activities broke macroaggregates into smaller fractions leading to carbon loss, even in the most stable mineral-bound carbon pool. We evaluated the effects of the soil rehabilitation technique under study, profile rebuilding, on soils exposed to these typical land development practices. Profile rebuilding incorporates compost amendment and deep tillage to address subsoil compaction. In the subsurface soils, profile rebuilding increased carbon storage in available and aggregate-protected carbon pools and microbial biomass which could partially offset soil carbon loss resulting from land development. Yet, urban soil rehabilitation increased greenhouse gas emissions while typical land development resulted in similar greenhouse gas emissions compared to undisturbed soils. Additionally, rehabilitated soils had higher saturated soil hydraulic conductivity in subsurface soils compared to other practices which could help mitigate stormwater runoff in urban areas. In our study, we found urban soil management practices can have a significant impact on urban ecosystem service provision. However, broader study integrating urban soil management practices with other ecosystem elements, such as vegetation, will help further develop effective strategies for sustainable cities. / Ph. D.

Orientador: Ely Nahas / Banca: Fábio Martins Mercante / Banca: Maria José Valarini / Banca: Antônio Carlos Monteiro / Banca: Roberto Alves de Oliveira / Resumo: Diversos estudos vêm buscando avaliar os diferentes impactos causados pelas várias formas de manejo do solo, procurando-se aliar a produção das culturas à preservação dos recursos naturais. O presente estudo objetivou avaliar a influência temporal (das estações do ano), do sistema de manejo do gado e das culturas nas características microbiológicas e químicas do solo em diferentes profundidades. O primeiro experimento foi conduzido no setor de bovinocultura da Estação Experimental da Faculdade de Ciências Agrárias e Veterinária, UNESP - Campus de Jaboticabal, localizada na região norte do Estado de São Paulo. Os sistemas de pastejo avaliados foram: pasto rotacionado, pasto contínuo e pasto controle (sem a presença de gado). As coletas das amostras de solo foram realizadas nas quatro estações do ano, no período de um ano (2005 - 2006). Cada amostra foi composta de 6 amostras simples, retiradas nas profundidades de 0 - 0,05, 0,05 - 0,10 e 0,10 - 0,20 m. O segundo experimento foi realizado nas fazendas Barracão e São João, no município de Guaíra, localizadas na região paulista da Alta Mogiana, Estado de São Paulo. Foram estudados quatro sistemas de manejo das culturas: plantio direto (PD), plantio direto integrado com pastagem (PD-I), cultivo convencional (CC) e Mata Natural (Mata). A coleta das amostras de solo foi feita somente na estação do verão, durante o período de janeiro e fevereiro do ano de 2006. Cada amostra foi composta de 10 amostras simples, retiradas nas profundidades de 0 - 0,10, 0,10 - 0,20 e 0,20 - 0,30 m. As variáveis microbiológicas, bioquímicas e químicas do solo avaliadas podem ser consideradas medidas sensíveis para determinar mudanças decorrentes dos efeitos das estações do ano, dos sistemas de manejo do gado e das culturas e da profundidade do solo. / Abstract: Several, studies come searching evaluated the different impacts caused by some forms of management of soil, to try to get the production of the cultures to the preservation of the natural resources. The objective of this study was determine the influence of the seasonal, of the cattle management system and crop and the depth of the soil in the microbiological and chemical variable of the soil. The first experiment was lead in the sector of cattle breeding of the Experimental Station of the College of Agrarian Sciences and Veterinary medicine, UNESP - Campus of Jaboticabal, located in the north of São Paulo State. The evaluated systems of pasture were: rotation pasture, continuous pasture and controlled pasture. The collections of soil samples were carried in four-year seasons during the period of one year (2005 - 2006). Each sample was composed of 6 simple samples, withdrawals with hoe, in the depths of 0 - 0,05, 0,05 - 0,10 and 0,10 - 0,20 m. The second experiment was carried in the Barracão and São João farms, in the Guaíra Cite, located in the region of the Alta Mogiana, in São Paulo State. In view of evaluation of the effect of the management system crop, four systems were studied: no-tillage (NT), pasture and crop integrated systems (PD-I), conventional tillage (CC) and forest. The collection of soil samples was made in summer, during the period of January and February in 2006. Each sample was composed of 10 simple samples withdrawals with hoe, in the depths of 0 - 0,10, 0,10 - 0,20 and 0,20 - 0,30 m. The evaluated microbiological, biochemical and chemical variables of soil can be considered sensitive measurements to determinate changes due to the effects of year seasons, the cattle management system and crop and the depth of the soil. / Doutor

A matéria orgânica e a biomassa microbiana do solo consistem em sensíveis indicadores de qualidade do solo e de seus estoques de carbono e nitrogênio que, juntamente com a textura, têm auxiliado na escolha de formas de manejo agronômico mais sustentáveis. Os métodos disponíveis para a determinação da matéria orgânica (Walkley-Black modificado da EMBRAPA SOLOS, 1997) e da biomassa microbiana (Vance et al., 1987a) têm sido largamente utilizados, porém possuem alguns inconvenientes como a geração de resíduos altamente tóxicos e a grande demanda de tempo para analisar um pequeno número de amostras. A espectroscopia, por sua vez, tem se mostrado uma alternativa mais rápida e limpa para a identificação e quantificação de compostos orgânicos. Por esse motivo, este trabalho teve como objetivo testar métodos espectroscópicos, tanto no infravermelho próximo (NIRS) quanto no médio com refletância difusa (DRIFTS), com o uso de calibração multivariada, para a quantificação destes indicadores. Os teores de argila, silte, areia, carbono orgânico total e carbono microbiano, assim como o quociente microbiano (CMIC/COT), foram espectrometricamente preditos de modo satisfatório. Em geral, obtiveram-se melhores resultados utilizando DRIFTS. / Organic matter and microbial biomass are sensible ways to indicate soil quality as well as carbon and nitrogen stocks. These properties, added to clay, silt and sand contents, have been helped to choose sustainable agronomic soil managements. Current methods for organic matter (Walkley-Black modified by EMBRAPA SOLOS, 1997) and microbial biomass (Vance et al., 1987a) determinations have been widely used despite the generation of toxic waste and large time requirement for analyzing a small number of samples. Spectroscopy, in turn, has been shown a clean and rapid alternative method for this purpose. Thus, the aim of the study was to evaluate the near-infrared reflectance spectroscopy (NIRS) and the mid-infrared diffuse reflectance spectroscopy (DRIFTS) on soil organic matter, microbial biomass and texture determination. Clay, silt, sand, total organic carbon and microbial carbon contents as even as microbial quotient are accurately quantified by infrared spectroscopy. In general, DRIFTS provided better results.

Mudanças de uso da terra afetam a dinâmica da matéria orgânica e o acúmulo de C e N no solo e estão associadas a emissões de gases de efeito estufa (GEEs). A região Amazônica é relevante para as emissões brasileiras de GEEs oriundas das mudanças de uso da terra. O objetivo deste trabalho foi determinar alterações quantitativas e qualitativas nos estoques de C e N no solo em função de mudanças de uso da terra em Santarém-PA e São Luís-MA. Foram coletadas amostras de solo sob diferentes usos da terra: vegetação nativa, vegetação secundária, pastagem degradada, pastagem melhorada e agricultura anual. Adicionalmente, foram avaliadas áreas de mata queimada em Santarém-PA e de fruticultura e horticultura em São Luís-MA. Houve diferenças entre os solos de vegetação nativa nos dois locais, apesar dos estoques de C e N terem sido similares. Em Santarém, fósforo e granulometria relacionaram-se aos estoques de C e N. Em São Luís a acidez potencial ajudou a estimar o estoque de C; granulometria e capacidade total de troca de cátions estimaram o estoque de N. Os estoques de C e N na vegetação secundária foram similares aos da vegetação nativa nos dois locais e relacionaram-se com a acidez potencial do solo. Em Santarém o estoque de C (0-30 cm) na pastagem melhorada foi maior que na vegetação nativa. Em São Luís, o estoque de C foi semelhante ao da vegetação nativa. Os estoques de N tiveram comportamento similar aos estoques de C. Na pastagem melhorada de Santarém a soma de bases foi importante para estimar os estoques de C e N; em São Luís houve efeito negativo da densidade do solo. Estoques de C e N nas pastagens degradadas foram semelhantes à vegetação nativa, mas foram influenciados por parâmetros diferentes. Áreas de agricultura anual apresentaram estoques de C inferiores aos das pastagens melhoradas e da vegetação nativa e a sua manutenção relaciona-se com a redução da acidez potencial e com o aumento das bases trocáveis. A qualidade da matéria orgânica do solo foi avaliada nas amostras de São Luís. A mudança de uso da terra reduziu o C na fração orgânica (75-2000 ?m), mas os usos mais conservacionistas aumentaram o C nas formas estáveis (< 53 ?m). Vegetação secundária e pastagem recuperada apresentaram índice de manejo de C semelhantes aos da vegetação nativa. A conversão de vegetação nativa para agricultura ou pastagem reduziu o C na biomassa microbiana, mas os sistemas com grande aporte de material orgânico e com reduzida mobilização do solo apresentaram teor de C microbiano similar à vegetação nativa. Pastagem e agricultura também apresentaram os menores quocientes microbianos, indicando condição de estresse da biomassa microbiana. / Land use changes affect organic matter dynamics and the accumulation of C and N in the soil and are associated with greenhouse gas emissions (GHGs). Amazon region is relevant to Brazilian GHG emissions from land use changes. The aim of this study was to determine quantitative and qualitative changes in C and N stocks in the soil due to land use changes in Santarém (PA) and São Luís (MA). Soil samples were collected under different land uses: native vegetation, secondary vegetation, degraded pasture, improved pasture and annual agriculture. Additionally, we evaluated burnt forest areas in Santarém (PA) and fruit-growing and horticulture in São Luís MA. There were differences between the soils of native vegetation in both sites, despite the C and N stocks were similar. In Santarém, phosphorus and soil particle size were related to C and N stocks. In São Luís potential acidity was used to estimate C stock; soil particle size and total cation exchange capacity estimated N stock. C and N stocks in secondary vegetation were similar to those of native vegetation in both sites and related with the soil potential acidity. In Santarém C stock (0-30 cm) in improved pasture was greater than in native vegetation. In São Luís, C soil stock was similar to that of native vegetation. N stocks had similar behavior to C stocks. In improved pasture of Santarém sum of bases was important to estimate the C and N stocks; in São Luís there was negative effect of soil density. C and N stocks in degraded pastures were similar to native vegetation, but were influenced by different parameters. Annual agricultural areas had C stocks below those of improved pastures and native vegetation and its maintenance is related to the reduction of soil potential acidity and to the increase of soil exchangeable bases. Quality of soil organic matter was evaluated in samples of São Luís. Land use changes reduced the content of C in organic fraction (75-200 ?m), while more conservationists uses have increased the C in stable shapes (< 53 ?m). Secondary vegetation and improved pasture presented carbon management index similar to native vegetation. Conversion of native forest to agriculture or pasture reduced the C microbial biomass, but systems with large organic material input and with reduced tillage presented microbial C content similar to native vegetation. Pasture and agriculture also presented the smallest ratios of microbial biomass C to total organic C, indicating stress of microbial biomass.