Impacto de atividades antrópicas, provocadas pela inserção da cultura da soja, sobre a microbiota e atributos físico químicos de solos no bioma cerrado

Abstract

The growth of the worldwide demand for food, especially in underdeveloped countries, has contributed for the increase of the incorporation of new plots of areas covered by native forests to the agricultural production systems. To the detriment of that, in the Brazilian land, one of the biomes that is losing natural area for the agropastoral systems in a fast way is the Cerrado, neglecting the impacts on the biodiversity, in large extent, especially the area that is below the limit line that separates the lithosphere from the atmosphere. That area comprehends the arable layer, the environment where there can be found part of the living organisms, that are responsible for the degradation of the organic matter, and the contribution of the mineralogical rock deterioration that form the mineral soils, prevailing in that biome, being the soybean crop (Glycine max) among the ones of largest expansion in the Cerrado. In this reasearch, the impacts of the soybean cultivation on the phisicochemical and biological attributes of the soil were evaluated. Using the sampling by conglomerate procedure, there have been selected three productive regions; in each of them, it was selected a productive unit, through casual sampling, and starting from the systematic sampling, the gathering stations were demarcated, inside the planting and the native forests areas. With the measurement and analysis of those attributes, the results showed that the soils that contain the highest concentration of sand are more susceptible to the clay movement and nutrient leaching, when the native covering is removed in order to introduce the soybean crop; the environmental reserves are constantly impacted by chemical substances introduced in the planting areas; the anthropic activities cause more impacts on the soil microbiota in the water shortage period and that microbial activity presents direct relationship with humidity and organic matter and inverse relationship with the Ph and the soil depth. Thus, to mitigate the impact of the native vegetal covering substitution by the agricultural planting, the adoption of conservationist practices is needed, such as: the terrace cultivation and directly on the hay.