Relationships between sediment, moisture and soil crust characteristics in arid environments
From a geomorphological point of view, and environments are characterised by
complex process interactions and suites of landforms which can be sensitive to their
controlling parameters. Relationships between sediment, moisture and soil crust
characteristics are no exception. Field research and a programme of laboratory study
were undertaken between 1993 and 1995 on the soils of the northern Badia of Jordan
to advance knowledge on aspects of and zone soil dynamics, with a particular
emphasis on crusting.
The research focuses primarily on the effect soil crusts have upon the equilibrium of
sediment dynamics at a hillslope scale and a ridge-furrow scale. The implications of
the crust upon moisture storage within the surface layers of the soil are examined and
the spatial characteristics which arise due to management practices and climate
variables considered. A new, non-destructive dielectric technique to investigate
moisture content in dryland soils has been developed and tested.
Monitoring has taken place to examine the effects of irrigation upon the surface
characteristics of the surrounding soil, with special reference to evaporation fluxes
within a furrow and the associated precipitation of salts. The role of small-scale
topography tends to be underestimated. Different types of crust have been studied
from various topographic locations. Soil fabric and porosity have been studied, to
increase understanding of micro-scale depositional and erosional processes. A new
method of tracing' fine material through the upper soil profile has been developed.
As crusts form, the tracer can be used to monitor the movement of fines, permitting a
much clearer understanding of soil and water dynamics as a result of rainfall events.