Movimento de Água e porosidade dos solos de uma sub-bacia hidrográfica no noroeste do estado de São Paulo

Abstract

Lack of environmental planning and inadequate occupation of soils in watersheds have caused their degradation. This study was conducted in the Jardim Novo Horizonte subwatershed in Ilha Solteira city, northwestern São Paulo state. This region has environmental problems such as soil erosion and river sedimentation. The study aimed at evaluating the effect of soil porosity in the Jardim Novo Horizonte subwatershed on water movement in order to evaluate the susceptibility to erosion processes. The most representative soils in the subwatershed are classified as Oxisol and Alfisol. Six and four spots, with five replicates each, were evaluated in the first and second soil, respectively, amounting to ten spots along the subwatershed. Soil uses were as follows: one area cropped with mango, four areas cropped with pastures and one area with annual crop in the Oxisol soil; two areas with pastures, one area with annual crop and one area with degraded vegetation in the Alfisol. Water movement in the Jardim Novo Horizonte subwatershed is related with soil macro porosity, total porosity and bulk density. The soils of the subwatershed showed physical properties under a degradation process, mainly porosity and bulk density, which affects water dynamics in these soils. Less permeability and therefore, more susceptibility to erosion of these soils could be the result of this process along the time.