Aggregation Index in Representative Soils of the Paraiba State

Brazil in Different Stages of Pedological Development

Abstract

The stability of soil aggregates is an important physical parameter as it mainly influences the flow of water and air in the soil. In this sence, the research aimed to determine the stability aggregates index in six representative soil classes in the Paraíba State-Brazil at different stages of pedological development. The soil classes analyzed is localized on the Microregions of the Curimataú Occidental (Ferrasol, Planosol, Leptosol, Arenosol) and Brejo Paraibano (Acrisol, Lixisol), on the Paraíba state, Brazil. At depths of 0-5 cm, 5-10 cm and 10-20 cm was collected three undeformed soil samples were collected per mini trench (one per depth), making a total of 15 samples per soil class and 90 total samples.  In each soil class was analysed: chemical parameters, granulometrics parameters, stability of agregates,  Weighted average diameter via wet sieving (DMPAu) and Weighted average diameter via dry sieving (DMPAs); agregate stability index (IEA). For the conditions that research was developed can conclude that: The IEA values tended to increase with clay contents in all soil classes; Among the less developed soils, the IEA values were better in the  Planosol soil, denoting that there is a probable relationship with the low contents of K, Na and Al; In the more developed soils, the high values of Na and Al may have contributed to the lower IEA in the PVd, while the lower values may have contributed to the higher IEA in Ferrasol and Lixisol soils.