PHOTOGRAPHIC INTERPRETATION OF THE DRAINAGE NETWORK FOR SOILS DISCRIMINATION

Abstract

Photointerpretation of the drainage network was used to discriminate soils developed from the same parent material and with an argilic B horizon, of the Basin Onça, in Presidente Prudente county - São Paulo State. The drainage network analysis was carried on 35 third order of ramification watersheds, from which were selected 4 watersheds groups (Areas) by geometric similarities and dimensional analysis. The drainage network was made on the following parameters of the composition: number, total lenght and mean lenght of rivers segments, and parameters of the drainage pattern: drainage density, frequency of rivers, texture ratio and topographic textural class. For statistical analysis data were added the ones of directed questionnaire related to the use and management of the soils. The main conclusions are the following: -The geometric similarities and dimensional analysis were able to discriminate genetically similar soils formed from the same parent material, but with different depth, different texture of the argilic B horizon and in different types of relief; -The composition of the drainage network: number, total lenght and mean lenght of the rivers segments discriminate the soils of the Areas, showing that they have different hydrophysical behaviour; -The genetically similar soils composition and characteristics of the drainage pattern vary with depth and relief; -The ajustement of the number, total length and mean length of the rivers segments equations showed that the drainage network follows the hidrophisical and Horton & Strahler laws and that their development takes place with the equilibrium with environment, is a consequence of the adequade use and management of the soil in accordance with the ambiental elements; - Soil use with pasture predominates in the area (67,6%), followed by agriculture (26,8%) and forest or reforestation (5,6%).