Abstract Copaiba (Copaifera langsdorffii Desf.) has suffered from continuous extractivism due to its medicinal properties, deforestation and urban expansion, despite having important medicinal and economic characteristics, this species lacks basic information, such as its adaptation to different types of soil. The objective of this study was to evaluate the nutrient content in soil and leaves of copaiba in different phytophysiognomies (Cerradão and Semideciduous Seasonal Forest (FES)). Plant tissue and soil samples were collected in the Cerradão and FES areas for analysis. The values of plant tissue nutrients were relatively similar, however, Nitrogen, Potassium, Copper and Boron were higher in FES, while in Cerradão, Calcium and Manganese was higher. The analyzes of both soils showed that they can be considered with good initial fertility due to the obtained values (V%: 50 for FES and 52 for Cerradão) in addition to show a low percentage of clay. It is expected that these data will contribute to the understanding of the plasticity that the species has under different ecological conditions.

Resumo A copaíba (Copaifera langsdorffii Desf.) tem sofrido com o extrativismo contínuo devido às suas propriedades medicinais, desmatamento e expansão urbana. Apesar de possuir características medicinais e econômicas importantes, essa espécie carece de informações básicas, como por exemplo, em relação à sua adaptação a diferentes tipos de solo. O objetivo desse estudo foi avaliar os teores de nutrientes em solo e folhas de copaíba em diferentes fitofisionomias (Cerradão e Floresta Estacional Semidecidual (FES)). Foram coletadas amostras de tecido vegetal e de solo em área de Cerradão e FES para análises. Os valores de nutrientes do tecido vegetal apresentaram-se relativamente semelhantes, no entanto, Nitrogênio, Potássio, Cobre e Boro foram superiores em FES, enquanto, no Cerradão, o Cálcio e o Manganês mostraram-se superior. As análises de ambos os solos demonstraram que estes podem ser considerados com boa fertilidade inicial devido aos valores obtidos (V%: 50 para FES e 52 para Cerradão), além de apresentarem baixa porcentagem de argila. Espera-se que estes dados contribuam para o entendimento da plasticidade que a espécie possui em diferentes condições ecológicas.

This paper presents a study on the production of silica gel in hydrothermal process using residual rice husk ash. Measurements of the chemical composition, X-ray diffraction, infrared spectroscopy, particle size distribution, and pozzolanic activity were carried out in order to characterize the obtained material, and the optimal silica gel was selected for use as a mineral additive in cement pastes. The compressive strengths were determined for cement pastes containing silica gel (0.0, 2.5 or 5% by mass) in different times. The results indicate that the mixtures containing silica gel showed improved mechanical behavior over all time periods evaluated.