Índices geomorfométricos e teores de ferro em solos da bacia do Rio Jirau

Abstract

The Soil is an organism with physical, chemical and biological components. Since the beginning of agriculture, the development and reproduction of the most diverse species of plants is a substrate and cradle for the germination and consequently it is of great importance for the life of any living being on planet Earth. Several factors can de-structure the interaction of the soil with the environment. The management action of the most different kinds of soils should be as efficient and balanced as possible. In this way, knowing techniques that can help us predict what occurs in the most diverse types of soils and environments is fundamental. The hydromorphic soils clearly reflect the variations of the environment, indicating the intensity of saturation by water of a temporary (plinite) or permanent (geization) form, also representing a component of great fragility in the ecosystem, since they are susceptible to the events of flood, they do not have great capacity of retention of pollutants, besides regulating the local hydrology. For such importance, these soils are protected by law, forming a permanent preservation area. The study of topography, through satellite images, can help in the better understanding of the spatial distribution of the chemical and mineralogical attributes of a given area. The present work has the objective of proposing an alternative to minimize time and resources for the recognition of areas with hydromorphic soil. Therefore, the water catchment area of the Jirau River will be studied in the municipality of Dois Vizinhos. The topography of the basin will be evaluated by means of a Digital Terrain Model of SRTM orbital origin with spatial resolution of 30 m, serving as the basis for the elaboration of Geomorphometric Indexes, which characterize the properties of the terrain. For the correlation with the hydromorphic soils, samples were collected from lowland, transition and well drained soil samples, which were submitted to laboratory analyzes to identify organic carbon and Fe oxides. The results of the analyzes were compared with the Geomorphometric indices ITW and MRVBF, and of this comparison it was possible to observe that in the scale used the indices were not efficient in the prediction of Fe and Organic Carbon oxides.