Geographia Technica, Vol 14, Issue no.1/2019, pp. 14-35


Denis Conrado da CRUZ, José María Rey BENAYAS, Gracialda Costa FERREIRA, André Luis MONTEIRO, Gustavo SCHWARTZ (Alcalá de Henares, Spain & Belém, Brazil)

DOI: 10.21163/GT_2019.141.02

ABSTRACT: Over the last decades, the natural environment has been degraded at a much greater speed than its own resilience. Lack of knowledge about soil natural limitations and mismanagement can increase their degradation and nutrient losses by erosion. The objective of this study was to estimate and map soil vulnerability to erosion through the Universal Equation of Revised Soil Loss (RUSLE) and based on the ecodynamic concept of physical and biotic environment analysis, and finally to evaluate conservation practices in the municipality of Paragominas with the economic database of IBGE / SIDRA. In the two analyzed methods the percentage of area with low and high potential and erosivity estimation were similar. The estimation of low and low-moderate loss and vulnerability represents about 77% (15,064 km2) of the territory by RUSLE and 60% (11,485 km2), by ecodynamic concept. The high to very high soil loss zones represent only 3% (642 km2) and 2.7% (584 km2), in the RUSLE and ecodynamic concept, respectively. Most of the variables analyzed in both methods presented low estimation values of loss and erosivity potential. The soil and slope attributes, for example, obtained exactly 79% (15,377 km2 - RUSLE) and 80% (15,572 km2 - ecodynamic concept), except for the climate and factor R attributes, in both methods the vulnerability potential and erosion, were only 1.5% (292 km2) and 1.3% (253 km2), based on the ecodynamic concept and RUSLE respectively. The geospatial analysis of the use practices correlated with the economic data showed an intense use of agricultural activities, logging and mining, which caused severe environmental damages, considering that 45% (8,773.3 km2) of the municipality have already been deforested and converted into other uses. The municipality still has 47% (9,182 km2) of its territory covered by altered primary vegetation and 23% (4,441 km2) by secondary vegetation, important information to subsidize decision-making processes related to ecological-economic strategies for the management of natural resources in the study area.

Keywords: Agriculture, Environmental variables, Potential for soil loss, Amazon

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