Relationships between microbial activity and soil physical and chemical properties in native and reforested Araucaria angustifolia forests in the state of São Paulo, Brazil

Abstract

SUMMARYAraucaria angustifolia (Bert.) O. Kuntze is the main component of the Mixed Ombrophilous forest and, in the State of São Paulo, it is associated with a high diversity of soil organisms, essential for the maintenance of soil quality, making the conservation of this ecosystem a major and pressing challenge. The objective of this study was to identify the physical and chemical properties that are most closely correlated with dehydrogenase enzyme activity, basal respiration and microbial biomass under native (NF) and replanted (RF) Araucaria angustifolia forests in three regions of the state of São Paulo, in winter and summer. The main differentiating factors between the areas were also determined. Each forest was represented by three true replications; at each site, from around the araucaria trees, 15 soil samples (0-20 cm) were collected to evaluate the soil physical, chemical and microbiological properties. At the same points, forest litter was sampled to assess mass and chemical properties. The following microbiological properties were evaluated: microbial biomass carbon (MBC), basal respiration (CO 2 -C), metabolic quotient (qCO 2 ), dehydrogenase enzyme activity (DHA) as well as the physical properties (moisture, bulk density, macroporosity and total porosity), soil chemical properties [pH, organic carbon (org-C), P, Ca, K, Mg, Al, H+Al], litter dry mass, and C, N and S contents. The data were subjected to analysis of variance (Two-way ANOVA). A Canonical Discriminant Analysis (CDA) and a Canonical Correlation Analysis (CCA) were also performed. In the soil under NF, the values of K, P, soil macroporosity, and litter dry mass were higher and qCO 2 and DHA lower, regardless of the sampling period, and DHA was lower in winter. In the RF areas, the levels of moisture, porosity and qCO 2 were higher in both sampling periods, and DHA was higher in winter. The MBC was only higher under NF in the summer, while the litter contents of C, N and S were greater in winter. In winter, CCA showed a high correlation of DHA with CO 2 -C, pH and H+Al, while in the summer org-C, moisture, Mg, pH and litter C were more associated with DHA and CO 2 -C. The CDA indicated H+Al, available P, total porosity, litter S content, and soil moisture as the most discriminating variables between NF and RF, but moisture was the most relevant, in both seasons and CO 2 -C only in winter. The combined analysis of CCA and CDA showed that the contribution of the microbiological variables to a differentiation of the areas was small at both samplings, which may indicate that the period after reforestation was long enough to allow an almost complete recovery of the microbial activity.Index terms: multivariate analysis, soil quality, soil chemical properties, microbiological properties. RESUMO: RELAÇÃO ENTRE ATIVIDADE MICROBIANA E ATRIBUTOS FÍSICOS E QUÍMICOS DO SOLO EM FLORESTA DE Araucaria angustifolia NATIVA E REFLORESTADA NO ESTADO DE SÃO PAULO A Araucaria angustifolia (Bert.) O. Kuntze é a principal componente da Floresta Ombrófila Mista n...

Economic and soil quality indicators in soybean crops grown under integrated crop-livestock and winter-grain cultivation systems

“…The sites were considered true replicates with respect to the studied systems (PEREIRA et al, 2013;BARTZ et al, 2014a).…”

Fertilización organomineral y NPK en el cultivo maíz (Zea mays L.)

“…Existem diferentes formas de monitorar a qualidade do solo, dentre elas destaca-se o uso de indicadores biológicos, especialmente na avaliação da fauna edáfica (Pereira et al, 2013). Sendo que os organismos edáficos possuem a capacidade de apresentar resposta rápida as mudanças na qualidade do solo, característica que não é observada nos indicadores físico-químicos.…”

REGENERAÇÃO NATURAL DE <i>Ocotea odorifera</i> (VELL.) ROHWER (LAURACEAE) EM FLORESTA OMBRÓFILA MISTA, PARANÁ, BRASIL

“…De acordo com Pereira et al (2013), o processo de decomposição promovido pela atividade TABELA 1: Altura e perímetro a altura do peito (PAP) das árvores-matrizes de Ocotea odorifera, seguida pelo seu número de indivíduos, altura, diâmetro a altura do solo (DAS) e densidade dos regenerantes, espessura da serapilheira e intensidade luminosa nas dez parcelas amostradas na RPPN Uru, Lapa, Paraná, Brasil. * Caules ramificados.…”