Soil
erosion is the most important form of soil degradation: it is estimated that
one-sixth of the world's soils have already been degraded by water and wind
erosion. This has two important consequences: the reduced ability of society
to produce sufficient food due to loss of quality and depth of soils; and the
off-site pollution effects associated with erosion. These include siltation
of dams, pollution of watercourses by agricultural chemicals and damage to property
by soil-laden runoff. On-site issues of declining soil quality tend to be spatially
dispersed occurring on many different soil types whereas off-site pollution
issues tend to be locally concentrated.
Soil erosion problems are not confined to the Developing World.
In the last two decades there has been a growing appreciation of the threat
to European soils as a result of intensification of agriculture, overgrazing
and climate change. The threat is most apparent in the Mediterranean region
where the term "desertification" has been used to describe a series
of inter-related changes which include soil erosion. The EU-funded MEDALUS (Mediterranean
Desertification and Land Use) project is currently addressing these latter issues
for much of southern Europe. However, regional and national research programmes
in erosion lack coordination.
Global change in the future threatens to further increase erosion
problems. Land-use change is a direct and immediate cause of erosion: most changes
of land use unfortunately increase the risk of erosion; this is particularly
the case with changes from grazing systems to arable farming because the area
of bare ground is increased. Some of the world's major arable crops such as
maize and soya beans are high risk crops. A major problem in many areas is overgrazing
as numbers of livestock are increased. Climate change is also a major threat
in that bare or poorly vegetated soils are vulnerable to increases in storm
activity, wind velocity or drought. Not all climate change is bad but together
with changes in land use, farming practice and population pressure on the land,
it often constitutes a threat of increased erosion. Because these changes are
widely perceived as a serious threat in the future, predictive tools are required
in order to anticipate their distribution and scale.
In northern Europe on the belt of fertile loess-rich soil stretching
from southern England to the Ukraine erosion has been a problem since the advent
of agriculture but has accelerated in recent years with the introduction of
mechanized intensive farming methods. Soils in some areas are thin and of declining
fertility. Off-site pollution including damage to property by soil-laden runoff
is a recurring problem and particularly well documented in Belgium, France,
Germany, the Netherlands and the United Kingdom. Rivers such as the Rhine
and the Meuse are carrying much higher loads of sediment and agricultural chemicals
than formerly.
Research on soil erosion is carried out worldwide but European
workers contribute in a major way to this effort. Centres of excellence occur
in Europe particularly in the areas of field and laboratory experimentation
on erosional processes, field monitoring of erosion, and the development and
application of erosion models for global change purposes. In many areas European
workers lead the world. In contrast, efforts in the USA, the other major
research centre, have concentrated on the development of large-scale erosion
models and the application of soil conservation technologies to the field. Although
there are many overlaps, research on either side of the Atlantic has tended
to have distinct agendas. This COST Action would aim to build on existing European
research themes but would relate closely to global concerns with the development
of predictive models.
The COST Action builds upon a worldwide collaborative analysis
of erosion models organized under GCTE
(Global Change and Terrestrial Ecosystems) but develops it in three related
topics specifically designed to focus on European cooperation and research themes
of particular relevance to the region.
Global
change includes climate change, change in atmospheric composition and land use
change through time. The latter is particularly important for soil erosion.
It is driven by demographic, economic, social and technological factors, as
well as by changing climate. These driving forces are not independent but are
strongly interactive.
There are three main objectives:
1. To make realistic predictions of the impacts of changes in
land-use and climate on soil erosion across a range of temporal and spatial
scales.
2. To identify critical thresholds in the landscape and soil
profile which lead to irreversible changes in the rate and style of soil erosion;
and also to develop indicators that forecast irreversible change.
3. To identify, assemble and make available datasets pertaining
to historic and current erosion.
The scientific outcome of the Action will contribute to the development
of better predictive tools, including models, and the design of effective ameliorative
procedures. The Action will therefore contribute to combating land degradation,
improving food supply, and reducing off-site pollution associated with erosion
events. Practical benefits will apply both to European countries and to the
Developing World to which much European research is directed. The development
of predictive tools for application in the Developing World benefits both local
communities and also, indirectly, Europe in the decreased reliance on aid. As
a consequence of the Action, knowledge and awareness of soil erosion will be
increased and recommendations for policy-makers will be framed.
Coordination of European research in soil erosion is needed.
There is no organization or structure that attempts to bring together researchers
on a regular basis, and which provides support within a planned thematic programme.
Research
into soil erosion and global change is very broad and overlaps into areas such
as climate change, vegetation and crops, food security and hydrology. An associated
group, as outlined in section A, has made progress with the testing and
application of erosion models. For these reasons we intend the COST Action to
focus on three areas where research has been lacking and/or poorly coordinated
between individuals and groups. We believe that the benefits of a coordinated
approach will be felt particularly in these areas. We propose three themes,
each coordinated by a Working Group.
1. Linking erosion processes across
temporal and spatial scales
Most erosion research has been conducted at one particular scale
and has ignored the problems of transfer of results to other scales. Traditionally,
erosion research has taken place on a small experimental plot or in the laboratory.
Results from these experiments have been difficult or impossible to transfer
to the field and landscape scale at which actual erosion occurs. To achieve
this we need to understand:
(i) how erosion processes at different spatial and temporal scales
interact;
(ii) how coarser scale processes act as constraints to processes
causing erosion at smaller scales; and in turn,
(iii) how the dynamics of finer scale processes lead to threshold
conditions that enable erosion to occur at higher levels (e.g. soil aggregation
controlling thresholds for sealing and crusting, and how sealing controls thresholds
for rilling and gullying).
Thus the Action will improve our understanding of some of the
scale issues that bedevil research into soil erosion and global change. This
part of the integrated research programme will aim to answer some fundamental
questions:
(i) What are the most important processes for the various spatial
and temporal scales in various environments (intensively cultivated, rangeland,
semi-natural and natural land), and what are their boundary conditions?
(ii) How do soil erosion processes at different scales interact
at each scale with other processes of soil degradation and with hydrological
processes such as infiltration and runoff generation?
(iii) How will global change affect scale relationships between
erosion processes? Can we expect relationships to remain constant?
2. Key thresholds for soil erosion
The soil resource must provide suitable conditions for plant
growth and land surface stability. This will be achieved by maintaining good
soil structure, a capacity to hold water, an appropriate supply of nutrients
and adequate vegetation cover to protect against erosion. Loss of soil quality
or quantity may be reversible up to a point if land management is improved.
Most soils however reach thresholds beyond which recovery is very slow. The
rate of soil formation is usually many times slower than even modest rates of
soil erosion. Although it may be obvious when these thresholds have been crossed,
it is usually very hard to know when a threshold is imminent. It is important
for the maintenance of soil health that we identify the approach of these thresholds,
so that remedial action can be taken in good time. In many cases this is made
possible because some critical states are not true thresholds but rather critical
ratios for which the balance of processes crosses a safe value.
Examples of critical ratios and thresholds are:
The ratio of soil organic matter production to decomposition
and loss by water and wind erosion.
The ratio of exchangeable sodium to total cations (which greatly
influences the degree to which clays disperse, and the maintenance of good soil
structure).
The decrease in depth of productive soil (soil truncation) which
may expose poorer and more sensitive subsoil. This threshold relates to issues
of food security: the ability of people to produce sufficient food is partly
controlled by soil quality and quantity.
The formation of rills and gullies in the landscape which gives
rise to a massive increase in erosion rates. This threshold is important in
influencing off-site pollution events: almost all cases of damage (sediment
and chemical) to watercourses and property by runoff from agricultural land
relate to rilling and gullying.
The Action will address these threshold issues many of which
have been neglected or suffer from fragmented research effort. An integrated
approach is likely to yield useful results. Three specific questions will form
the focus of this section of the Action:
(i) At what level and when is the loss or decline of a given
function critical?
(ii) What are the processes and properties responsible for soil
resilience, and what are their predictive indicators?
(iii) How can the approach of rilling and gullying be better
predicted?
These questions relate to practical issues in land management.
Advances made by the Action are likely to feed into and improve existing soil
erosion models and also to have useful applications in advice to farmers, land
managers and those concerned with off-site pollution.
3. Datasets for erosion studies
Understanding of erosional processes, assessment of areas at
risk, prediction of future rates, all depend on datasets of past and current
erosion. Datasets may be at various spatial scales: experimental plots, fields
or watershed but their value is enhanced if they cover long periods. Much useful
data is dispersed, for example, as climate, land use and soil surveys but can
be brought together and utilized via a GIS framework. Datasets are
of particular value for calibration and validation of models. Modern computer-based
models require detailed small area data whereas the construction of broad-brush
predictive tools such as the CORINE project also require large datasets plus
a feel for the reliability and variability of the data. Issues of climate change
and land use change are difficult to deal with without long-term datasets but
in many countries such data is lacking or difficult to come by. There are exceptions
and these should be explored; for example, the Italian State Archives cover
several centuries of farm history and include description of land use, major
accidents and crop productivity. In the United Kingdom parish-level land-use
data can be linked to climate; records of erosion are more unusual although
local newspapers often record flooding and property damage events. Many researchers
are unaware of the potential of such records.
Evaluation of the effects of future land use and climate change
on soil erosion are enhanced if local and regional datasets are available. Principal
end-users are modellers; predictions and scenarios can then be made available
to policy makers.
The Action will address the issues of
1. the effect of changing management strategies on erosion;
2. the effect of changes of climate including the frequency of
extreme events.
These issues will be examined interactively since feedbacks occur
between management, climate and erosion.
A
management committee (MC) including the elected Chairperson, Vice-Chairperson,
Working Group (WG) coordinators and representatives appointed by the Signatories
of the MoU will be set up following the signing by the appointed number of signatories
to the MoU. The MC will work out its rule of operation at its first formal meeting
in accordance with existing COST regulations. The MC will meet twice a year
to review progress.
The partners will elect a Chairperson and a Vice-Chairperson
who will be responsible for coordinating activities and ensuring that the Action
direction meets the overall objectives.
The following three WGs will be formed:
WG 1 Linking erosional processes across spatial and temporal
scales
WG 2 Key thresholds for soil erosion
WG 3 Datasets for erosion studies.
Each WG will elect a Coordinator who will assist the Chairperson
and Vice-Chairperson in ensuring that the work is of a high standard. Overseeing
the activities of each WG will be the responsibility of the MC.
The duration of the Action is planned for five years.
The organizational structure is shown in Figure 1. Coordination
of the Action is achieved by means of Annual Workshops. Working Groups will
meet twice a year. An inaugural MC meeting prior to the first Annual Workshop
will elect Coordinators for the WGs. The Action will be concluded with a major
conference oriented to policy makers. This should be in cooperation with allied
groups such as the European Society
for Soil Conservation and MEDALUS.
Links to other research groups and dissemination of results to
a wider audience will be achieved by integration of some COST Action WG meetings
into international scientific meetings.
A major publication in a Special Issue of an international journal
or an edited book will be the end product of each WG. A publication committee
for each WG will be established at the year 3 Annual Workshop.
To facilitate interaction between meetings the Internet will
be used in two ways. The first is by means of an e-mail-based Discussion List.
This would enable dialogue to be maintained between meeting participants. The
second is by setting up a Web Site dedicated to the themes of the COST Action;
this would act as a vehicle for publicising the aims and achievements of the
Action to the wider scientific community.
The establishment of links with other groups will be important
for the success of the COST Action WGs. This is especially valuable because
much of the research activity planned under this Action is interdisciplinary.
WG 1 will establish links with GCTE
Task 3.3.1 for soil organic matter and structural stability, and with GCTE
Task 3.3.3 for interactions between soil biota, infiltration and soil detachability.
WG 2 will collaborate with the above two groups and also with
Land Use and Cover Change (LUCC): a joint
project of IGBP and the
International Human Dimensions Programme (IHDP).
WG 3 will explore links with Past Global Changes (PAGES)
of IGBP.
A related but quite distinct programme is the Concerted
Action on Mediterranean Desertification (EC DG XII, Climatology
and Natural Hazards Unit). It is envisaged that there will be cooperation with
this Concerted Action particularly in the area of indicators of land quality
which is part of Theme 3. Several researchers are common to both the Concerted
Action and the planned COST Action and these links are regarded as extremely
beneficial. Several potential researchers also have strong links to past and
current EU-funded programmes such as CORINE
(Coordinated Information on the Environment) and MEDALUS.
The Action will also explore cooperation on erosion issues with the European
Environment Agency, the Climate
and Environment Programme of DG XII, and the European Soil Bureau at
ISPRA, particularly in relation to the development of the 150 000 scale
soil map of Europe.
The
following COST countries have actively participated in the preparation of the
Action: (1) Belgium, (2) France, (3) Germany, (4) Greece, (5) Italy, (6) the
Netherlands, (7) Spain, and (8) the United Kingdom.
On the basis of national estimates provided by the representatives
of these countries and taking into account the coordination cost to be covered
over the COST budget of the European Commission, the overall cost of the activities
to be carried out under the Action has been estimated at 1997 prices, at roughly
ECU 46,5 million. The figure is based on estimates of numbers of researchers
working on soil erosion issues in each country with a notional cost of ECU 75 000
per man-year for a full-time research position: Belgium (20 researchers), France
(50), Germany (7), Greece (3), Italy (3), the Netherlands (9), Spain (12)
and UK (20).
The estimate is valid on the assumption that all the countries
mentioned above, but no others, will participate in the Action. Any departure
from this will change the total cost accordingly.
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