Environmental diagnosis from declivity, erosivity, erodibility and the SAVI Index in the semi-arid region of Piauí: a case study in the city of Juazeiro do Piauí

Abstract

The objective of this study was to characterize the environmental components, to evaluate and to diagnose the state of the natural environment of the city of Juazeiro do Piauí, using biophysical variables. The study used quantitative-qualitative methodology and descriptive approach, using the Physical Conservationist Diagnosis (PCD) and the USUAIS and QGIS computational programs. Thus, the minimum value 6 was delineated to represent the best environmental quality and the maximum value 19 for the worst conservation status. The studied area is based on the sedimentary geological formations Cabeças (78.2%) and Pimenteiras (21.8%). The relief presents altitudes that vary from 100 to 260 m, predominating flat slope to smooth undulating. The municipality is cut by the rivers Poti and Parafuso and stream Vertente and has precipitations that oscillate between 900 to 1.200 mm. The following soil suborders were identified: Yellow Latosols (44.6%), Lithoidal Neosols (39.2%), Quartzarenic Neosols (13.1%) and Planossolos Háplicos (3.1%). These soils are covered by herbaceous stratum to more full-bodied trees and closed rock. The descriptive formula of the PCD indicated an increase of the environmental degradation in the municipality of Juazeiro do Piauí of the order of 1,067 units, considering the years of 1997 (11,448) and 2016 (12,515). This increase is possibly associated to the dynamics of economic activities and climatic oscillations, which interfere with the growth of the vegetation cover. Therefore, the data should be taken as key elements for territorial planning and the management and recovery of the environmental framework in the municipality.