masterThesis
Resposta da capacidade de sorção de fósforo do solo a ocupação urbana em ecossistemas tropicais
Fecha
2021-12-15Registro en:
CUNHA, Giulliana Karine Gabriel. Resposta da capacidade de sorção de fósforo do solo a ocupação urbana em ecossistemas tropicais. 2021. 35f. Dissertação (Mestrado em Engenharia Sanitária e Ambiental) - Centro de Tecnologia, Universidade Federal do Rio Grande do Norte, Natal, 2021.
Autor
Cunha, Giulliana Karine Gabriel
Resumen
Phosphorus (P) is naturally present in soils. Changes in land use can promote additional
inputs of P into the soil that lead to saturation of binding sites exceeding the maximum
sorption capacity of P in the soil. Besides P input, urban occupation promotes changes in
soil attributes that contribute to intensify soil vulnerability to erosion and P flux from soil
to aquatic ecosystems, aggravating the water crisis, especially in the semiarid region. The
objective of this study was to evaluate the sorption characteristics of P in urban soils and
to verify their relationship with soil attributes. A total of fifty soil samples, twenty-five
of natural and twenty-five of urban soils were selected from different watersheds in the
state. The soil samples were characterized physically and chemically. The P sorption
characteristics were obtained by fitting the Langmuir and Freundlich equations.
Descriptive statistics, Pearson correlation and Principal Component Analysis (PCA) were
used to analyze these data. Urban soils showed lower P sorption capacity. The increase
of P-rem, pH, available P and reduction of clay contents occurred concomitantly with the
increase of phosphorus saturation index and the reduction of soil P sorption capacity in
urban soils, being good indicators of P source soils in watersheds. Lower Smáx, clay
content and Freundlich constant 1/n best distinguished natural from urban soils regarding
P sorption. The results show the reduction of P sorption capacity in soils, increasing its
mobility in watersheds and the risks related to P loads in aquatic ecosystems with urban
expansion worldwide. These data serve as a basis for decision making regarding the
appropriate management of soils in urban expansion areas in watersheds in order to
control the flux of P to aquatic systems.