Variability of some physical, chemical and physico-hydrical characteristics in Red Yellow Podzolic soils from Seropédica, RJ

Abstract

The objective of this study was to evaluate fundamental parameters of the distribution of some physical (particle size, soil and particle densities and porosity percentage); chemical (organic carbon contents) and physico-hydrical properties (water retention and hydric tension) in Red Yellow Podzolic soils, varying their texture from loamy sand to loamy sand clay, in Seropédica, Rio de Janeiro. The variability of some studied characteristics was evaluated according to three levels of analysis (global, by profile and by depth). It was concluded that: the average characteristics of the bulk and particle densities farther than the total porosity were sufficiently sampled in the three considered levels; the particle size and organic carbon were sufficiently sampled at the global analysis level in the whole studied surface, however for the profile analysis and the depth analysis in PVe3, the sample number was insufficient. Data variability of the water retention increased when the water tension level increased for all analysis levels and the variability increased linearly with the increase of the sampling distance of the points. The sandy soils showed higher variability than the other soils, suggesting denser sampling for the physical, chemical and physico-hydrical characteristics than the other soils of clayey texture. The results showed that those properties studied were very well sampled and that the variability of the water retention was positively related to the level of the water tensions.