Environmental Engineering Reference
In-Depth Information
Watershed scale
Slope scale
Patch scale
Plant structure:
canopy, leaf surface, root, litter
intercept the rainfall and fix the soil
Patch characteristics of vegetation:
shape,
density, and size of vegetation affect rain
interception and storage;
Soil property:
affect the water infiltration;
Meteorological factors
:
rainfall, temperature;
wind speed;
Runoff:
diversified into different
streams; and transferredinto
evaporation; infiltration; affect
the side leakage
Climate factors:
the spatial and
temporal patterns of rainfall
affectsoil erosion intensity;
Spatial pattern of physical
factors:
vegetation configuration
and soil property pattern
pattern;
Human activities:
land use
policy
Runoff:
intercepted or
infiltrated, affect the
micro climate
Topographic factors:
Slope degree affects runoff
speed, features affects
water-heat, and micro
landform affects water
redistribution;
Human activities:
land
use strategies
Fig. 1.3
Mechanisms of landscape patterns on runoff and soil erosion at various scales
Table 1.1
Leading factors affecting landscape patterns and soil erosion processes at different
scales
Scale
Patch scale
Slope scale
Watershed scale
Impact factors
Plant characteristics
Vegetation and soil patch
configuration
Vegetation and soil
pattern
Soil property
Topography
Land use pattern
Meteorological factors
Meteorological factors
Climate
Disturbance
Disturbance
Disturbance
water flow (Wang et al.
2006
). On the other hand, soil erosion affects the vegetation
pattern by altering water content and soil redistribution and accumulation, which
further drive the dynamics of the landscape pattern (Wilcox et al.
2003
).
1.4.1 Landscape Patterns and Soil Erosion Processes
at Patch Scale
In semi-arid areas, landscape pattern at the patch scale is characterized by the
spatial variabilities of vegetation and soil properties (Ludwig et al.
2005
), while
soil erosion is directly affected by runoff, infiltration, and interception. Vegetation
plays an active role in reducing surface flow (Reid et al.
1999
), lowering runoff
speed, and increasing soil water content (Li et al.
1991
), as well as influencing
biomass (Noble et al.
1998
) and bioactivity (Roth et al.
2003
), and alleviating soil
erosion (Ludwig et al.
2005
). The canopy and leaf surfaces absorb the energy of
rain drop splashes and effectively intercept the rainfall (Liu et al.
1994
), while the
root systems help fix the soil and improve its physical properties (Li et al.
1991
).
The litter not only enhances the soil's anti-erosion capacity (Hu and Shao
2001
)
and increases infiltration (Ludwig et al.
2005
), but it also helps foster a sound
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