THE ABILITY TO UNDERSTAND AND THE TEXTUAL TYPOLOGIES IN THE PRIMARY BASIC EDUCATION, THIRD GRADE

The objective of this research was to evaluate how the physical properties of a soil (Cambisol) were influenced depending on the type of management. For this, three areas with different types of management were defined: soil without disturbance under forests for more than 50 years (Reference); soil under pasture area of more than 10 years (Conserved) and cultivated soil (Agrogenic), determining the following physical variables: textural composition, humidity, porosity, plasticity and structural stability index. The results signify significant differences for the textural composition of the soil, with the highest percentage reaching the clays, in the grass profile, and the fine sand in the forest profile. The humidity presents the highest values in the depths of 0-13 cm in the forest floor, 18-42 cm in the cultivated soil and 25-45 cm in the grass soil. In the soil profile under forest, from 0-25 cm, the total porosity fluctuated between satisfactory to excellent with 57% of pores, while the profiles under pastures and crops show very low values. The values of the plasticity and structural stability indices in the pasture profile were higher than in those of forests and crops, in general, they decrease with depth. The changes in the soils originated alterations in the apparent and real density, humidity, porosity and in the structural stability.