|
1. Definition
| Name |
AREA OF MARGINAL SOIL USED |
| Brief
definition |
Area
of soil cultivated that is less productive, or more likely to
be affected by degradation processes. |
| Unit of measure |
Ha (also %
of total cultivated area) |
| Spatial scale |
|
| Temporal scale |
|
2. Position
within the logical framework DPSIR
| Type of Indicator |
State (pressure
on some processes or issues) |
3. Target and
political pertinence
| Objective |
The
objective of this indicator is to measure the sensitive areas
which are on risk of degradation because of the land use. |
| Importance
with respect to desertification |
Marginal
soils are the most sensitive to degradation processes when being
cultivated or abandoned after cultivation. It is necessary to
measure and to protect (perhaps by aforestation) these areas
in order to avoid degradation processes. |
| International
Conventions and agreements |
The UNCCD emphasizes
that combating desertification must be tackled within the general
framework of actions to promote sustainable development.
|
| Secondary objectives
of the indicator |
Contribution
to the definition and mapping of ESAs and assessment of the
desertification risk of an area. It can also be an indicator
of the pressure that agricultural activities are putting on
environment. |
4. Methodological
description and basic definitions
| Definitions
and basic concepts |
The
main problem in defining this indicator is that there is not
a generalized definition of "marginal soil". Both
the general productivity and degradation processes have to be
considered. A brief and simple definition can be used: "soil
characterised by a low fertility status and a high risk of erosion".
As these lands are, by definition, less productive, an increased
effort is required in order to supply enough food. The methods
used tend to be not sustainable as marginal lands tend to be
steeper, more rocky, with shallow topsoil and low organic matter
levels. All of these features increase runoff and erosion rates.
It is important to mention that even though marginal soils are
usually associated with steeply sloping areas it is not always
the case. It is necessary to include soils on shallow slopes
that are also at high risk of suffering degradation processes.
Areas marginal soil are also the most likely to be abandoned
first. |
| Benchmarks
Indication of the values/ranges of value |
The area of
marginal soil used is measured in Ha. |
| Methods
of measurement |
It
is possible to measure the area of marginal soil used using
statistics, maps, GIS or, necessary in many cases, field surveys. |
| Limits
of the indicator |
The
definition of marginal soil must be specified for each area.
On shallow slopes, marginal soil is not easy to measure if not
enough data at field level are available. |
| Linkages with
other indicators |
This indicator
is linked to Land abandonment from
agriculture (since this kind of soils are the most likely
to be abandoned first). It is also linked to Soil erosion, Soil
quality index, Soil type, Land
use evolution, Area of hill slope cultivated, Tillage
operations |
5. Evaluation
of data needs and availability
| Data
required to calculate the indicator |
Area
of land cultivated in marginal soils (considering to be on steep
slopes, with low organic matter levels, rocky or with shallow
topsoil). |
| Data sources |
Necessary data
are usually available and accessible and the cost/benefit ratio
is reasonable. Agricultural statistics and data from subsidies
programs, such as agri-environmental measures programs. The
use of GIS methods is particularly useful to detect cultivated
areas on slopes. |
| Availability
of data from national and international sources |
Data can be
obtained from various regional, national or international institutions
involved in the collection and the analysis of geological data.
|
6. Institutions
that have participated in developing the indicator
| Main institutions
responsible |
University
of Murcia |
| Other
contributing organizations |
Agricultural
University of Athens , Universities of Lisbon, Greece, Basilicata,
Amsterdam, Leeds |
7. Additional
information
| Bibliography
|
Commission of the European
communities. COM 2001(144). Statistical information needed
for indicators to monitor the Integration of Environmental
concerns into the Common Agricultural Policy
Jo de baerdemaeker, Dirk
J. Oostwoud Wijdenes, Jean Poesen, Liesbeth Vandekerckhove,
Jeroen Nachtergaele. Gully-head morphology and implications
for gully development on abandoned fields in a semi-arid environment,
Sierra de Gata, Southeast Spain. Earth Surface Processes and
Landforms 24, 585-603 (1999)
|
| Other references |
|
| Contacts
Name and address |
Prof. Francisco lópez-Bermúdez
<lopber@um.es>
Jorge García Gómez <jorgegg@um.es>
Area de Geografía Física
Universidad de Murcia
Campus de La Merced
Aulario General (Lab. geomorfología)
30001 Murcia
España
|
|
