『Abstract
Soil erosion plots of different types and sizes are widely used
to investigate the geomorphological processes related to soil
erosion. This field method has provided variety of results, depending
on the characteristics of the plots, on their suitability to reflect
the ecosystem's characteristics and on the objectives of each
particular research. The coupling of real soil loss at patch and
slope scale within a landscape and the values obtained by field
plots depend, among other things, on how good the methodology
performs over a set of ecosystem properties, such as those related
with temporal and spatial scale issues, disturbance and representation
of natural conditions, and the ability to account for the complexity
of ecosystem interactions. Here, we present a review of (i) the
advantages and limitations of the use of field plots to measure
soil erosion; and (ii) the potential sources of variation in the
results obtained due to a lack of harmony between methodological
conditions and the processes operating in the environment at different
scales.
As regards the spatial and temporal scales of measurements, topics
such as the exhaustion of available material within closed plots
in long term measurements, the different erosion processes operating
(and measured) at different spatial scales and the problems and
alternatives of extrapolation of the results from larger to smaller
scales, are the main causes of variation between measurements.
The disturbance and inadequate representation of natural conditions,
such as the heterogeneity, continuity and connectivity of factors
and processes, are also sources of variation in the results of
specific measurements. In short, the key factor is the difficulty
to encapsulate the complexity of system interactions and to represent
these interactions by means of field plots. The complexity concept
is translated in the connectivity of water and sediment fluxes
in the landscape and the interaction between processes and patterns
of vegetation and surface components operating across scales.
Keywords: soil erosion; erosion plots; field methods; spatial
pattern; scale-dependence; exhaustion of material; connectivity;
water fluxes; sediment redistribution』
1. Introduction
2. Temporal scale of measurements
3. Spatial scale of measurements
3.1. Processes operating at a range of scales
3.2. Direct extrapolation from plots to smaller scales versus
new approaches
4. Representation and disturbance of natural conditions
4.1. Disturbances of connections and interactions within
the system
4.2. The use of replica plots
5.l Complexity of system interactions
5.1. Connectivity issues
5.2. Processes and patterns
5.3. Relations across scales
6. Conclusions and recommendations
Acknowledgements
References