Variability of soil erodibility: its relationship to topography and soil properties in cultivated landscape
Date
1989
Authors
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Journal ISSN
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Publisher
ORCID
Type
Degree Level
Masters
Abstract
The hypothesis of this thesis is that soil erodibility varies systematically with
landscape topography. This hypothesis was tested by using a portable rainfall
simulator to measure the relative soil erodibility at five slope positions along
eleven slope transects on fallow agricultural land in hummocky terrain. Soil
erodibility variations among the five slope units were examined for significant
differences. The slope units were found to be ranked in descending order by
mean soil erodibility as follows: shoulder, midslope, footslope, summit,
toeslope. This systematic pattern of erodibility was evident even though
topographic characteristics and soil properties varied substantially between the
slope transects sampled within the small study area. Differences in erodibility
were attributed to soil property differences along the slopes. Correlation and
multiple regression indicated that soil properties had a stronger relationship to
soil erodibility than did topographic variables. Particle size distribution, bulk
density and organic matter had the most significant effect on erodibility
variations. Aggregation measures were not found to be good indicators of soil
erodibility. Topography was thought to influence erodibility indirectly
through its effect on the distribution of soil properties along the slope
transects based on the higher correlations between topographic variables and
many soil properties. Higher correlations between erodibility and soil and
topographic variables were found when analyzed by slope position, especially
on the midslope. This indicates that soil properties were more uniform when grouped by slope position than when considered as a single, large data set.
This study suggested that the use of a catena approach to examine soil
erodibility is an important consideration when studying soil erosion processes
in agricultural landscapes.
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Degree
Master of Science (M.Sc.)
Department
Geography
Program
Geography