FATORES CONDICIONANTES DA AGREGAÇÃO EM SOLOS SOB DIFERENTES USOS E DESENVOLVIMENTO PEDOGENÉTICO

Abstract

The soil aggregation defines the interaction between the shape, size and arrangement of the solid particles and porous space of the soil, been a dynamic characteristic and associated with the physical, chemical and biological factors, in other words showing how the ground is suceptable to fragmentation by physical changes, such as erosion, chemical as the action of chemical elements or biological activity with the beings that inhabit the soil environment. With this, the objective of this study was to evaluate the soil aggregation behave according to physical and chemical factors of soil under different land use conditions in a Oxisol and Entisol. Undisturbed soil samples were collected at 0-10 and 10-20 cm deep in a Oxisol and Entisol under three conditions of use (native forest, pasture and cultivated). Determining the physical characterizations were performed soil texture, soil and particle density, porosity, aggregate stability and chemical characterization by determining pH (H2O); P; K+; Ca2+; Mg2+ and Al3+ interchangeable; organic carbon and some of its established relationships. The type of soil with higher clay was the Oxisoil which conditioned greater degree of flocculation, lower clay dispersion values and therefore higher aggregate specifically provided under native forest, observing higher weighted diameter values of aggregates and consequently greater aggregate stability index. The Oxisoil showed better aggregation condition represented by the physical properties and higher values of the chemicals elements of the flocculating serie, such as calcium, potential acidity, magnesium and especially the organic matter, which is a determinant of aggregation.