SOIL CHEMICAL ATTRIBUTES RELATIONSHIPS AROUND THE Araucaria angustifolia TREES IN AGROFORESTRY SYSTEMS

Abstract

This work aimed to understand the relationships between araucaria trees and some abiotic factors (soil type, soil organic C and soil nutrient supply) in agroforestry systems (AFS). Soils of two production areas in south-central region of the state of Parana (Bituruna - B and São Mateus do Sul - M) were characterized and soil chemical attributes were determined in microsites close to araucaria trees. B area presented only “juvenile” trees, while M area was formed by “juvenile” and “adult” trees. According to the multiple linear regression analyses, the soil chemical attributes showed an almost total dependence of the microsites depth. Soil chemical attributes dependence was much more diffuse in relation to the distances from the tree insertion in the soil. The non-metric multidimensional scaling ordination according to soil chemical attributes showed a great overlap of behavior of these tree groups. The chemical attributes comparison generated, to a certain extent, a soil fertility deficiency gradient between the microsites of the three groups of trees (MJ < MA < BJ). AFS with shaded Ilex paraguariensis must consider the replacement of nutrients exported by leaf harvest, which will help in the sustainability of the activity. This includes the environmental services that the AFS promotes by maintaining, or even renewing, of the native trees from the local forest, especially araucaria trees, in a productive system.