Soils have an important task in maintaining vegetation cover and natural resources on Earth and are indispensable to societies. However, the accelerated soil erosion has become an environmental problem related to land settlement for agricultural practices and forestry and is linked to population growth. This study aimed to evaluate soil erosion in a watershed downstream of Parnaíba river, northwest of Piauí state, in the Brazilian Cerrado using geotechnology products and tools in order to understand the soil loss and map the potential erosion and actual erosion through qualitative and quantitative results to support the management and planning of the watershed in an effective and efficient way. As a modeling tool, this research used the Revised Universal Soil Loss Equation (RUSLE). The potential erosion ranged from very low to very high. The soil loss obtained by the integration of natural physical factors with land use (anthropic action) resulted in soil loss corresponding to the category slight (0–0.01 t.ha⁻¹.year⁻¹) to extremely high (>100 t.ha⁻¹.year⁻¹). The areas with the greatest soil loss were identified in land uses linked to pasture, exposed soil, and cultivated land. It was also possible to identify erosion features in the field, indicating the need to implement soil conservation practices.

The Brazilian northeast coast has tourism potential, and in the last decades its landscapes have been impacted by the expansion of tourism activity. The present research aimed to survey the change s that occurred in the evolution of soil cover in the municipality of Cajueiro da Praia, Piauí, in 2000 and 2015, using Remote Sensing and Geoprocessing techniques. The supervised classification of images LANDSAT 8 and LANDSAT 5, OLI/TIRS and TM imager instruments, respectively, in 2015 and 2000, using the Maxver method, processed in the Arcgis 10.2 software, made possible the production of the maps of use and coverage and the dynamics of land cover. The analysis identified nine classes of land use and land cover, which showed changes observed from the dynamics between the two dates. The analysis of these data, together with socioeconomic data from the census and surveys carried out by the Brazilian Institute of Geography and Statistics, showed a context of land use and land cover changes, with growth of urban areas, the increase of water bodies of the municipality. The change in the quantitative population of the municipality occurs perceptibly in its coastal area, the increase of water bodies is especially due to the growth of shrimp tanks. The issues of environmental legislation are factors that may explain the recovery of some vegetation areas, as their non-compliance explains the loss of others, such as mangrove vegetation, which was observed throughout the work.

This study investigates the impact of extreme rainfall events on soil erosion in the downstream Parnaíba River Basin, located in the Brazilian Cerrado. The analysis focused on rainfall erosivity (R factor) and soil erodibility (K factor) as key indicators. The average erosivity in the region was 9051 MJ mm h−1ha−1year−1, with a variation between 7943 and 10,081 MJ mm h−1ha−1year−1, suggesting a high erosive potential, mainly in the rainiest months, from December to April. The soils of the studied area, mainly Ultisols and Chernosols, present high to very high erodibility, with K factor values ranging from 0.025 to 0.050 t h MJ−1 mm−1. Furthermore, fieldwork revealed areas, near highways, with apparently fragile soils, as well as rills and gullies, identified through photographs taken during fieldwork. These locations, due to the combination of high erosivity and susceptible soils, were considered prone to the occurrence of erosion processes, representing an additional risk to local infrastructure. The spatialization of R and K factors, along with field observations, showed that much of the area is at high risk of erosion and landslides, particularly in regions with greater topographic variability and proximity to water bodies. These results provide a basis for the development of mitigation strategies, being important for the effective prevention of landslides.