Name: ÍCARO ALVES LOBO
Type: MSc dissertation
Publication date: 09/03/2022
Advisor:

Name	Role
EBERVAL MARCHIORO	Advisor *

Examining board:

Name	Role
DIOGO COSTA BUARQUE	External Examiner *
EBERVAL MARCHIORO	Advisor *
LUIZA LEONARDI BRICALLI	Internal Examiner *

Summary: Soil erosion is a problem which affects mankind harshly and directly impacts the
agricultural production, the hydric resources and topographical relief’s
configuration. Several mathematic models were developed to forecast and avoid
the catastrophic consequences caused by soil loss, aiming to estimate future
trends regarding the erosive behavior upon a determined area based on
topographic, climatic and land usage and cover parameters. Among these
models, one stand outs: The Universal Soil Loss Equation, developed by
Wischmeier and Smith in 1978, based on experimental plots observation in the
United States and, for being easily replicable and requiring a pretty simple
database, is widely accepted as a method of yearly soil loss through hydric
erosion estimation in several countries, especially after the rising and wide
adoption of Geographic Information Systems (GIS). The parameters for
calculating this equation are the rainfall erosivity (R), soil erodibility (K), the slope
length (L), slope gradient (S), cropping management factor(C) and the erosion
control practice factor (P). When these factors are multiplied, they result in the
total of yearly soil loss (A). In this study, the USLE was applied for the entire area
of Duas Bocas Watershed, located in the state of Espírito Santo, Brazil, with the
objective of identifying the frailest regions to be affected by the hydric erosion,
and also, to retrospectively analyze the evolution of the land coverage and usage
in this watershed since 1970 and its impacts on soil losses. Moreover, some
comparisons were made for the soil’s erodibility factor between the ones
registered in previous works with samples collected in situ throughout 39 points
using the indirect method proposed by Sharpley and Williams (1990), seeking to
check out if this method was adequate for obtaining the soil erodibility on the
study area, based exclusively in variables like soil granulometry and percentage
of organic carbon in the soil, without texture and the usage of Wischmeier and
Smith’s Nomograph.

Keywords: Hydric erosion – Geographic modeling – Erodibility

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