Atributos químicos e físicos de solos de referência e sua relação com a fragilidade ambiental na bacia hidrográfica do Rio Ivinhema - MS

Abstract

The advance of the agricultural frontier is growing in the Cerrado Biome, motivated by the production of meat and grains for export. Deforestation causes environmental concern, and in some regions of the Cerrado Biome they have already exceeded the limits for conversion of land use, and should be considered priority areas for carrying out environmental studies and monitoring. In this sense, aimed of this research was to evaluate chemical and physical attributes of reference soils and their relationship with environmental fragility in the Ivinhema River Basin, Mato Grosso do Sul. For this purpose, 62 soil samples were defined, representative of the geological and pedological units of the basin, in remnants of native vegetation. Deformed and undisturbed samples were collected to determine chemical and physical attributes in the laboratory. The results showed a great variety of soils inside the basin, whose natural fertility was high for the Leptsol, Regosol, and Nitisol soils, and low for the Argiluvic Plinthosol, Petroplinthic Plinthosol, and Planosol soils. The texture of the analyzed soils ranged from sandy to clayey, with particle size heterogeneity even within the same textural class. The predominance of medium sand and fine sand and, to a lesser extent, very fine sand, enables high particle adjustment capacity. Sandy soils associated with sandstone formations confer greater fragility to the environment when compared to basaltic clayey soils under similar environmental conditions. The fragility analysis showed that about 17,977 km2 or 47.7% of the area is composed of low potential fragility, associated with clayey soils and low slope (0 - 3%). The anthropic factor favors the increase of environmental fragility in the studied area, because, with the insertion of land use and land cover, high environmental fragility stood out in 16,795 km2 or 44.6% of the basin, especially with agriculture as the largest coverage found in the bowl. The data shown in research can fill the gaps of knowledge and/or for adapting conservation practices of agricultural soils that are more susceptible to erosive processes, as well as for environmental control and monitoring bodies and/or studies of area recovery and maintenance of soil fertility.