Destination of urban pruning organic waste by means of biochar applied to the soil: Analysis of the compactation curve / Destinação de resíduos orgânicos de poda urbana por meio de biochar aplicado no solo: Análise de curva de compactação

Urban pruning waste can have multiple uses from direct burning wood as energy to its use as organic fertilizers in the composting process. However, the lack of suitable places for the disposal of this type of waste is a problem for municipalities with large urbanization. Thus, “biochar” presents itself as an alternative proposal for the disposal of urban pruning organic waste. In this context, the present work aimed to verify the behavior of soil compaction curves through the application of biochar as a form of conditioning and waste disposal. Soil collection was carried out at the Institute of Science and Technology of Sorocaba (ICTS –UNESP Sorocaba) followed by drying and sieving for soil characterization through particle size analysis. The tests were performed with application of biochar in the soil using the Proctor Normal Compaction Test (NBR 7182/1986) at 35 t/ha and 70 t/ha in different textures. The data of the compaction curves and comparative statistical analysis presented satisfactory results. The results expose a maximum specific weight reduction and optimum humidity increase in all samples with application of biochar. Thus, the proposal for the redestination of urban pruning organic waste by means of biochar applied to the soil can be considered an alternative for urban management of pruning organic waste and may help in integrated solid waste management

Análise da morfométrica de agregados do solo em áreas mineradas em diferentes estágios de recuperação na Amazônia

Mining has a strong influence on the Brazilian economy, however, extractive activity results in multiple damages to the ecosystem, as vegetation and the surface layer of the soil are removed, altering the natural pedological characteristics. Therefore, programs for the recovery of degraded areas become essential to mitigate or compensate for negative impacts on the environment. In this way, the understanding of soil quality indicators has been worked on to evaluate the process of recovery of degraded areas. Thus, the objective of this work was to develop and test a new approach to qualify the recovery of soil aggregation and reference ecosystems in the Brazilian Amazon (RO). For this, the geometric mean diameter (DMG) and the morphometric parameters: area, circularity, roundness and Feret diameter of the soil aggregates were determined. The parameters were evaluated in five different aggregate sizes, 6.0 mm, 4.0 mm, 2.0 mm, 1.0 mm and 0.71 µm, then multivariate analysis of variance (MANOVA) was performed, comparing the morphometric variables and aggregate sizes from each study area. The results obtained show a positive correlation between the values ​​of area, circularity and Feret diameter of soil aggregates, indicating improvements in soil structure and vegetation. In this way, the proposed parameters demonstrated a high capacity to describe the soil quality and differentiate the recovery levels, presenting itself as an excellent indicator in the monitoring of degraded areas.A mineração exerce forte influência sobre a economia brasileira, no entanto, a atividade extrativista resulta em múltiplos danos ao ecossistema, pois a vegetação e a camada superficial do solo são removidas, alterando as características pedológicas naturais. Portanto, programas de recuperação de áreas degradadas tornam-se essenciais para mitigar ou compensar os impactos negativos ao meio ambiente. Dessa forma, o entendimento dos indicadores de qualidade do solo tem sido trabalhado para avaliar o processo de recuperação de áreas degradadas. Assim, o objetivo deste trabalho foi desenvolver e testar uma nova abordagem para qualificar a agregação do solo em recuperação e ecossistemas de referências na Amazônia brasileira (RO). Para isso, determinou-se o diâmetro médio geométrico (DMG), e os parâmetros morfométricos: área, circularidade, arredondamento e diâmetro de Feret dos agregados do solo. Os parâmetros foram avaliados em cinco tamanhos de agregados diferentes, 6,0 mm, 4,0 mm, 2,0 mm, 1,0 mm e 0,71 µm, em seguida foi realizada análise de variância multivariada (MANOVA), comparando as variáveis morfométricas e tamanhos dos agregados de cada área de estudo. Os resultados obtidos mostram uma correlação positiva entre os valores da área, circularidade e diâmetro de Feret dos agregados do solo, indicando melhorias na estrutura do solo e na vegetação. Dessa forma, os parâmetros propostos demonstraram alta capacidade de descrever a qualidade do solo e diferenciar os níveis de recuperação, apresentando-se como um excelente indicador no monitoramento de áreas degradadas