ABSTRACT The proper soil use and management are essential for a sustainable production, thus the pursuit for systems that minimize damages to the environment and improve soil fertility is continuous. The objective of this study was to evaluate changes in soil fertility by the use and management of an Oxisol (Latossolo Vermelho-amarelo, SiBCS) in the Amazon biome. The soil uses and management systems evaluated were native forest, native pasture, minimum tillage system and conventional tillage system. The chemical atributes of the soil layers 0.00-0.10, 0.10-0.20, 0.20-0.30 and 0.30-0.40 m were evaluated. The soil pH (CaCl2) and the contents of organic matter, available phosphorus and exchangeable potassium, calcium, magnesium and aluminum were evaluated and the saturation by Al, effective cation exchange capacity and soil potential were determined. The highest pH values were found in the native pasture area, and the highest exchangeable aluminum contents were found in the layers 0.00-0.10 and 0.10-0.20 m of the conventional tillage system. The highest phosphorus availability was found in the layer 0.00-0.10 m of the native forest area. The highest potassium availability was found in the minimum tillage system. The lowest calcium and magnesium values were found in the layers 0.00-0.10 and 0.10-0.20 m of the conventional tillage system. The highest soil organic matter content was found in the layer 0.00-0.10 m of the native forest area. The nutrient availability for plants decreases in soils managed using the conventional tillage system. Soil uses and management systems of little soil disturbance are recommended to minimize environmental degradation in the Amazon biome. | RESUMO O uso e manejo do solo adequados são fundamentais para a produção sustentável, sendo constante a busca por sistemas que minimizem os danos causados ao ambiente e que melhorem a fertilidade do solo. Objetivou-se avaliar as alterações nos atributos de fertilidade em decorrência do uso e manejo em Latossolo Vermelho-Amarelo (LVA) na Amazônia. Os seguintes sistemas de uso e manejo do solo num LVA foram avaliados: floresta nativa, pastagem nativa e áreas preparadas por sistema de cultivo mínimo e cultivo convencional. As avaliações dos atributos químicos do solo foram realizadas nas profundidades de 0 -0,10, 0,10-0,20, 0,20-0,30 e 0,30-0,40 m. Foram avaliados o pH do solo (CaCl2), o teor de matéria orgânica do solo, os teores de fósforo disponível e potássio trocável, cálcio, magnésio e alumino trocáveis, sendo ainda determinados a saturação por Al, a capacidade de troca catiônica efetiva e potencial do solo. Os valores de pH mais elevados foram verificados no sistema de pastagem nativa e os maiores teores de alumínio trocável nas profundidades de 0-0,10 e 0,10-0,20 m foram verificadas no sistema de cultivo convencional. O sistema de floresta nativa apresentou a maior disponibilidade de fósforo na profundidade de 0-0,10 m. As maiores disponibilidades de potássio foram verificadas no sistema de cultivo mínimo. Os menores valores de cálcio e magnésio nas profundidades de 0-0,10 e 0,10-0,20 m ocorreram no sistema de cultivo convencional. O sistema de floresta nativa apresentou o maior teor de matéria orgânica do solo na profundidade de 0-0,10 m. A disponibilidade de nutrientes para as plantas é reduzida em solos manejados em sistema de plantio convencional. Os sistemas de uso e manejo de menor revolvimento do solo são indicados para minimizar a degradação ambiental na Amazônia.

ABSTRACT The intense anthropization in the lower São Francisco River and surrounding areas can lead to environmental degradation risks and, above all, makes the area more susceptible to soil erosion. This study aimed to identify and correlate the physical and chemical properties able to enhance erosive processes and slope instability in the watercourse margins of the lower São Francisco River, in Sergipe State, Brazil. To this end, disturbed and undisturbed samples of an Entisol-Fluvent soil were collected in the region, specifically in the city of Amparo de São Francisco. Physical (density, porosity, and texture) and chemical (pH, cation exchange capacity, base saturation, micro-, and macronutrients) analyses were performed. All physical properties and organic carbon contents were higher in the surface layers (Ap and AC) compared to the others. Organic carbon, phosphorus, and micronutrients had a negative correlation with soil density, showing higher contents and lower soil densities in the Ap and AC layers. The pedological characteristics of the evaluated soil layers are unable to provide soil resistance to water erosion.