Variables related to the stability of soil macro and microaggregates of a toposequence in the Brazil south region

Soil aggregates are the basic components of soil structure, being important to its environmental properties and functions. The objective of this study was to investigate the variables related to the aggregates stability, measured by the method of dry and wet sieving and by applying ultrasound energy, in three different soils of a toposequence in southern Brazil. The study was performed in three soils sampled in the city of Pinhais / PR: i) Oxisol (top slope); Ii) Inceptisol (medium third) and; Iii) Gleisol (floodplain). The aggregates stability was determined measured by the method of dry and wet sieving (macroaggregates), as well as by applying ultrasound energy (microaggregate). The results were correlated with soil chemical, physical and mineralogical attributes. The organic matter, the low crystallinity Fe oxides and kaolinite were the most important variables for the profile structural stability. In turn, the soil texture did not show a direct relation with soil aggregation. The Gleisol show highest structural stability, followed by Oxisol and Inceptisol.