Zoneamento do potencial de perda de solo e parâmetros de erodibilidade do solo no Sul do Amazonas

Abstract

The felling of forests for agricultural activities is a routine practice in the Amazon and this causes significant environmental impacts. The removal of vegetation cover causes a decrease in biodiversity, extinction of animal and plant species, desertification, erosion, reduction of soil nutrients, and contributes to global warming, among other damages. The search for tools that assist in environmental sustainability and conservation of soil resources is fundamental for planning and decision-making in areas with potential for soil loss and degradation. Therefore, this research is timely as it contributes to the survey of estimates of soil loss rates due to erosion, making use of important tools such as the Universal Soil Loss Equation – USLE, as well as the use of GIS tools, which enhances the mitigation of future environmental and social impacts as well as the preservation of soil resources. The present work aims to establish the zoning of soil loss potential and erodibility parameters in natural and man-made environments in the South of Amazonas. The study covers a strip of area located south of Amazonas, approximately 2500 km². In this range are areas with survey studies carried out since 2007 that include the municipalities of Humaitá, Manicoré and Apuí. The model for calculating potential erosion loss used was the Universal Soil Loss Equation (USLE) by Wischmeier and Smith (1978), with the aid of a Geographic Information System, the ArcGis 10.2.1 software, where the factors soil, rainfall, relief, land use and conservation practices will be spatialized for the entire area under study. Through this study it was possible to verify the sensitivity of the different regional equations developed to calculate the rain erosivity factor and soil erodibility in the observed areas. Regarding the influence of changes in soil use and occupation factors in relation to its erodibility, significant changes were observed in the distribution of areas in terms of erosive susceptibility between the four scenarios. It was also concluded that the highest erosivity averages occur between the months of january to march and october to december, due to the highest rainfall in the region, regardless of the scenario studied, just as the lowest averages occur between the months of june to august, the months of april and may and september to october are considered transitional periods between climatic periods in Amazonas. Finally, the application results indicate that the tool can be used to differentiate erosion potentials between areas with different land uses and occupation, different types of soil and different slopes, making it possible to create varied maps for the area under study, providing useful information for decision makers, who can prioritize and implement best management practices to reduce erosion load.