Actualité scientifique
N° 396
February 2012
More than three quarters of
the land in Mexico is
suffering from erosion.
Desertification is
accentuated partly by the
aggressive climate and
rugged topography but
mostly by human activity. The
phenomenon has led to
much activity since 1995:
politicians, authorities and
local communities have been
working together to create
sustainable management of
the natural resources in
water, forests and soil.
The drainage basin of
Morelia, the capital of
Michoacán, is emblematic of
the situation. A FrancoMexican team of researchers
from the IRD, UNAM,
UMSNH and ColPos1 have
selected the region as a pilot
study as part of the
REVOLSO, STREAMS and
DESIRE2 programmes, to
define the runoffs and
develop suitable strategies.
Actions have included
hydrological monitoring,
agronomic essays and
socio-economic studies, with
participation from local
communities, political bodies
and the authorities3.
Cultivation of alternative
crops such as agave – used
in the production of mezcal4
– has been initiated, enabling
a reduction in harm to the
environment and also a
improvement in revenue and
quality of life for local
inhabitants.
Actualidad cientifica
Rehabilitation of
eroded land in Mexico
© IRD / C. Prat
Scientific news
Extreme soil erosion, particularly in the Morelia region, is largely due to overgrazing.
Mexico is faced with a serious problem of soil degradation: 80 % of the land is subject to erosion. The
central state of Michoacán has one of the highest
levels of soil erosion, with more than 2 million
hectares affected, 70 % of the surface area. An
aggressive climate, rugged and changeable topography and fragile soils indicate that nature has
played a part. But it is human activity that is the main
cause, due to overgrazing. The derisory prices of
agricultural products has led to crop cultivation becoming a secondary resource for farmers, who have
either turned to livestock farming or abandoned their
land in order to migrate to the cities or the United
States.
A longstanding awareness
It has been over 15 years since political, civil and
scientific leaders decided to act together to face this
problem, initiating a programme of research and
actions. In 1995, Mexico ratified the United Nations
convention to combat desertification and created an
arsenal of laws and institutions that would protect its
natural resources. Since then, the number of multidisciplinary research programmes, both national
and international, has greatly increased, with the
intention of guaranteeing sustainable development.
Taking place over several years, they have developed to include an increasing number of social
partners, drawn equally from civil groups and from
the world of politics and administration.
Water erodes all in its path
The catchment area for Morelia, the capital of
Michoacán, is representative of the scale of erosion
in Mexico as a whole. The basin is surrounded by
chains of volcanoes up to 3,500 m in height, with the
steep slopes accelerating the runoff and thus the
hydraulic erosion. A Franco-Mexican research team
from the IRD, UNAM, UMSNH and ColPos1 have
selected this drainage basin as a pilot area to study
FOR MORE INFORMATION
Contacts
the phenomenon and its impacts, part of the
REVOLSO, STREAMS and DESIRE 2 research
programmes. The initial results have recently been
published.
Since 2002, researchers have been carrying out a
series of experiments and measures, notably monitoring erosion and flooding via hydrological monitoring. They have demonstrated deterioration of the
soil and diminished agricultural production, a
decrease in the infiltration of water into the soil that in
turn feeds the aquifers, an intensification of flash
flooding, as well as an increase in pollution of watercourses and at the Cointzio dam, which supplies
20 % of drinking water to the city of Morelia.
A participatory process
These works are the result of a shared initiative
between scientists, political authorities, administrative institutions3 and local populations, who have
been active for ten years in the region though consultations. For example, the inhabitants of the drainage
basin have played an active role in the studies,
through a process of community monitoring of hydrometric techniques and an adapted system of
sampling. The characterisation of the soil and its
physical and temporal decay, as well as the monitoring of water and sediment flow, has been made
possible due to their contribution. The choice of
crops and agricultural techniques tested has also
been the result of dialogue at participatory workshops. If suitable strategies are to be developed, the
environmental projects on offer should also be
economically viable. In particular, the agricultural
activities that are developed should ensure sufficient
revenue to attract and retain the young generation in
the rural area.
Christian Prat, IRD researcher
Tel. : +33 (0)6 31 52 05 29
christian.prat@ird.fr
A new concept: agave forestry
UMR 012 Laboratoire d’étude des transferts
en hydrologie et environnement – LTHE (IRD /
Université Joseph Fourier, Grenoble / CNRS /
Institut polytechnique de Grenoble - INP)
Nicolas Gratiot, IRD researcher
Tel. : +33 (0)4 76 82 50 92
nicolas.gratiot@ird.fr
The field reports and socioeconomic studies have
thus led to the testing of alternative cultivation
methods and types, enabling a better preservation of
the soil on the one hand, and economic and social
benefits on the other. Community greenhouses for
the cultivation of local species have been established. In particular, the cultivation of agave has
been developed. Used in the production of mezcal4,
this plant has a dual advantage in that it has strong
economic potential and also forms a barrier to
erosion. Associated with trees and shrubs, it can halt
runoff and also enable protection and recovery for
the soil.
Address
LTHE
Domaine universitaire
BP 53
38041 Grenoble cedex 9
References
Duvert Clément, Gratiot Nicolas, Némery Julien,
Burgos A., Navratil O. Sub-daily variability
of suspended sediment fluxes in small
mountainous catchments-Implications for
community-based river monitoring. Hydrology
and Earth System Sciences, 2011, 15 (3), p.
703-713. doi:10.5194/hess-15-703-2011
Prat C., A. Martínez Palacios et E. Ríos Patrón.
Restauration de sols dégradés de l’altiplano
mexicain par agaveforesterie. E. Roose et al.
Eds, In : Restauration de la productivité des sols
tropicaux et méditerranéens, IRD Montpellier,
250 p. In press.
Such results have led to the Morelia drainage basin
being adopted by the authorities, who have recently
declared it as a priority zone for action. Given the
current context of climatic and anthropic change, the
Mexican example shows that action in cooperation
with local institutions and populations can lead to the
establishment of sustainable solutions and offer rural
communities alternative sources of revenue, not just
a means of survival.
Schwilch, G., Hessel, R. and Verzandvoort, S. (Eds).
DESIRE for greener land. Options for Sustainable
Land Management in Drylands. Publishers
University of Bern - CDE, Alterra, Wageningen
UR and ISRIC - World Soil Information WOCATFAO. 250 p. In press.
Bravo Espinosa M., Mendoza M. E., Medina Orozco
L., Prat C., Garcia Oliva F., Lopez Granados E.
Runoff, soil loss, and nutrient depletion under
traditional and alternative cropping systems in
the transmexican volcanic belt, central Mexico.
Land Degradation and Development, 2009, 20
(6), p. 640-653. doi:10.1002/ldr.953
by Gaëlle Courcoux
www.desire-project.eu
Keywords
Mexico, degradation, erosion, water, soil,
cultivation
1. Universidad Nacional Autónoma de México, Universidad Michoacana San Nicolas de Hidalgo, Colegio de Postgraduados en Agrociencias
2. REVOLSO – Alternative agriculture for a sustainable rehabilitation of deteriorated volcanic soils in Mexico and Chile (UE 2002-2006)
STREAMS – Sediment transport and erosion across mountains (ANR 2005-2007) – DESIRE – Desertification mitigation and remediation land - A global approach for local solutions (UE 2007-2012).
Coordination
Gaëlle Courcoux
Information and Culture Department
Tel: +33 (0)4 91 99 94 90
Fax: +33 (0)4 91 99 92 28
fichesactu@ird.fr
www.ird.fr/la-mediatheque
3. The Secretaría de Medio Ambiente y Recursos Naturales (SEMARNAT), the Comisión nacional del agua (CONAGUA), etc.
4. alcoholic drink produced in Mexico from agave, much like tequila.
Indigo, IRD Photo Library
Daina Rechner
Tel: +33 (0)4 91 99 94 81
indigo@ird.fr
You can find IRD photographs on this topic, free
for media reproduction without additional:
www.indigo.ird.fr
Hydraulic measures in drainage basins, workshop with rural community as part of STREAMS and DESIRE and planting of agave to limit erosion and for mezcal
production.
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© IRD / C. Prat
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