1.2 Coordonnées des personnes-ressources et des institutions impliquées dans l'évaluation et la documentation de la Technologie

Nom du projet qui a facilité la documentation/ l'évaluation de la Technologie (si pertinent)

Nom du ou des institutions qui ont facilité la documentation/ l'évaluation de la Technologie (si pertinent)

1.3 Conditions relatives à l'utilisation par WOCAT des données documentées

Le compilateur et la(les) personne(s) ressource(s) acceptent les conditions relatives à l'utilisation par WOCAT des données documentées:

Oui

1.5 Référence au(x) Questionnaires sur les Approches de GDT (documentées au moyen de WOCAT)

Participatory catchment rehabilitation (Participación comunitaria para la rehabilitación … [Pérou]

Promoting the rehabilitation of ancient terrace systems based on a systematic watershed management approach.

• Compilateur : Philippe Zahner
• 16 jan. 2009 00:00

2.1 Courte description de la Technologie

Définition de la Technologie:

Repair of ancient stone wall bench terraces, and of an associated irrigation and drainage system.

2.2 Description détaillée de la Technologie

Description:

The level bench terrace system in the Colca valley of Peru dates back to 600 years AD. Since then the terraces have been continuously used for crop production, but due to lack of maintenance they have deteriorated, and the population has lost its traditional knowledge of repair.
The rehabilitation of the terraces recreates their original structural design. Broken sections are cleared and the various materials - stones, topsoil, subsoil and weeds - are removed and separated. The foundation is re-established, followed by construction of the stone wall (the ‘riser’). Backfilling with subsoil then takes place; this is consolidated and finally covered with topsoil. Simultaneously the complementary irrigation and drainage systems are reconstructed.
The rehabilitated terraces efficiently conserve soil and water on steep slopes, and they create a favourable microclimate for crops, reducing loss of stored heat at night by minimising air movement (preventing frosts) and mitigating dry conditions through moisture conservation. The main economic benefits are from increased yields and crop diversification.
Terraces are spaced and sized according to slope, eg on a 50% slope, terraces are 4 m wide with a 2 m high riser between terrace beds. Stones of ancient terraces had been widely used to build walls for boundary marking after privatisation of land, therefore a large amount of stone had to be provided by splitting rocks and transporting from other locations.
The area is characterised by steep slopes with loamy-sandy, moderately deep soils (on the terrace beds). Most of the annual precipitation (ca. 350 mm) falls within a period of 3 months, which makes irrigation necessary. The farmers in the area own, on average, 1.2 hectares of arable land, divided into around six plots in different agro-ecological zones. Production is mainly for subsistence. Important supportive technologies include agronomic measures such as improved fallow, early tillage, ridging, and intercropping. Tree and shrub planting at the base of terrace walls is an optional measure with the aim of stabilising the walls, diversifying production and again ensuring a good microclimate. On average 250 trees/ha are planted; these are mainly native species such as c’olle (Buddleia spp.), mutuy (Cassia sp.), molle (Schinus molle: the ‘pepper tree’) and various fruit trees including capulí (Prunus salicifolia).

2.3 Photos de la Technologie

2.5 Pays/ région/ lieux où la Technologie a été appliquée et qui sont couverts par cette évaluation

Pays:

Pérou

Région/ Etat/ Province:

Río Colca,Caylloma, Arequipa

Commentaires:

Total area covered by the SLM Technology is 100 km2.

Map

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2.7 Introduction de la Technologie

Spécifiez comment la Technologie a été introduite: :

• par le biais de projets/ d'interventions extérieures

3.1 Principal(aux) objectif(s) de la Technologie

• améliorer la production
• réduire, prévenir, restaurer les terres dégradées
• créer un impact économique positif

3.2 Type(s) actuel(s) d'utilisation des terres, là où la Technologie est appliquée

Terres cultivées

• Cultures annuelles

Cultures annuelles - Précisez les cultures:

• céréales - maïs
• cultures fourragères - luzerne
• légumineuses et légumes secs - fèves
• plantes à racines et à tubercules - pommes de terre

Précisez:

Longest growing period in days: 120 Longest growing period from month to month: Dec - Apr

Pâturages

Pâturage intensif/ production fourragère :

• Affouragement en vert/ zéro-pâturage

Commentaires:

Main crops (cash and food crops): Major food crop: Potatoes, maize,beans, etc
Main animal species and products: Alfalfa (cut and carry)

Major land use problems (compiler’s opinion): - Loss of productive capacity: 30% of the agricultural land lost due to degraded terraces, severe deforestation (through
cutting for fuelwood), overgrazing and burning of grazing areas.
- Inefficient irrigation practices (flooding) due to poor maintenance of irrigation system (and drainage system in poor
condition), flood irrigation leads to deterioration of terraces.
- Loss of traditional knowledge of ancestral crop management practices (abandonment of appropriate rotation practices, lack of residue incorporation/recycling, unsystematic crop layout).

3.4 Approvisionnement en eau

Commentaires:

Water supply: mixed rainfed - irrigated and rainfed

3.5 Groupe de GDT auquel appartient la Technologie

• mesures en travers de la pente
• gestion de l'irrigation (incl. l'approvisionnement en eau, le drainage)
• dérivation et drainage de l'eau

3.6 Mesures de GDT constituant la Technologie

structures physiques

• S1: Terrasses

Commentaires:

Main measures: structural measures

Secondary measures: agronomic measures, vegetative measures

3.7 Principaux types de dégradation des terres traités par la Technologie

érosion hydrique des sols

• Wt: perte de la couche superficielle des sols (couche arable)/ érosion de surface
• Wg: ravinement/ érosion en ravines

dégradation chimique des sols

• Cn: baisse de la fertilité des sols et réduction du niveau de matière organique (non causée par l’érosion)

dégradation hydrique

• Ha: aridification

Commentaires:

Main type of degradation addressed: Wt: loss of topsoil / surface erosion, Wg: gully erosion / gullying, Cn: fertility decline and reduced organic matter content, Ha: aridification

3.8 Prévention, réduction de la dégradation ou réhabilitation des terres dégradées

Spécifiez l'objectif de la Technologie au regard de la dégradation des terres:

• restaurer/ réhabiliter des terres sévèrement dégradées

4.1 Dessin technique de la Technologie

Spécifications techniques (associées au dessin technique):

Rehabilitated ancient terraces with high stone risers. Two options for irrigation and drainage of excess water are shown: outlets in the risers (left) and a broad water channel cutting perpendicularly through the terraces (right).

Technical knowledge required for field staff / advisors: high

Technical knowledge required for land users: moderate

Main technical functions: control of dispersed runoff: retain / trap, reduction of slope angle, reduction of slope length, increase of infiltration, water harvesting / increase water supply, improvement of microclimate

Secondary technical functions: control of dispersed runoff: impede / retard, control of concentrated runoff: impede / retard, increase in organic matter, increase / maintain water stored in soil, sediment retention / trapping, sediment harvesting, improvement of soil structure

Auteur:

Mats Gurtner

4.3 Activités de mise en place/ d'établissement

4.4 Coûts et intrants nécessaires à la mise en place

4.5 Activités d'entretien/ récurrentes

4.6 Coûts et intrants nécessaires aux activités d'entretien/ récurrentes (par an)

Commentaires:

Machinery/ tools: A-frame,tape measure,motor drill,wheelbarrow,shovel,pick,steel bar,sledgehammer,hoe,hand compressor.

Person days needed for rehabilitation of 1 ha of ancient terrace system depend on degree of deterioration, the dimensions of the wall, slope angle (the steeper the more terraces) and availability of stones. In the case of the project, under a typical situation, for physical rehabilitation of 1 ha with 6 terraces, each ca 600 m long, 3–4 m wide and 2 m high, with one third of the main structures in disrepair, 18 men and 7 women work for 5 days; shrub planting is extra. Land users bear 35% of the overall costs: they also provide food for the group during work. The programme pays the rest. 450 m3 of additional stones are required to repair the broken parts, the cost includes blasting/splitting rocks and transport to the construction site.
Supportive agronomic measures and agricultural inputs (seeds and manure) are not included. Maintenance costs vary considerably, depending on the specific situation: an average is taken here.

5.1 Climat

5.2 Topographie

Commentaires et précisions supplémentaires sur la topographie:

Landforms: Also hill slopes (ranked 2) and footslopes (ranked 3)
Slopes on average: Also hilly (ranked 2) and rolling (ranked 3)

5.3 Sols

Si disponible, joignez une description complète du sol ou précisez les informations disponibles, par ex., type de sol, pH/ acidité du sol, capacité d'échange cationique, azote, salinité, etc.

Soil fertility: Medium (ranked 1, used for maize) and low (ranked 2)
Topsoil organic matter: Low (low recycling of organic matter)
Soil drainage/infiltration: Medium

5.6 Caractéristiques des exploitants des terres appliquant la Technologie

Indiquez toute autre caractéristique pertinente des exploitants des terres:

Off-farm income specification: main source is wage labour in the valleys
Market orientation of grazing land production system: Subsistence (ranked 1) and mixed (ranked 2, 30% for market)
Market orientation of grazing land production system: Subsistence (ranked 1, complementary to crop production) and commercial/market (ranked 2, income generation to meet basic needs)

5.7 Superficie moyenne des terres utilisées par les exploitants des terres appliquant la Technologie

5.8 Propriété foncière, droits d’utilisation des terres et de l'eau

Propriété foncière:

• individu, sans titre de propriété
• individu, avec titre de propriété

Droits d’utilisation des terres:

• loué
• individuel

6.1 Impacts sur site que la Technologie a montrés

Impacts socio-économiques

Production

Revenus et coûts

Autres impacts socio-économiques

Impacts écologiques

Cycle de l'eau/ ruissellement

Sols

Biodiversité: végétale, animale

Autres impacts écologiques

6.2 Impacts hors site que la Technologie a montrés

6.4 Analyse coûts-bénéfices

Quels sont les bénéfices comparativement aux coûts de mise en place (du point de vue des exploitants des terres)?

Quels sont les bénéfices comparativement aux coûts d'entretien récurrents (du point de vue des exploitants des terres)?

6.5 Adoption de la Technologie

Si disponible, quantifiez (nombre de ménages et/ou superficie couverte):

240

De tous ceux qui ont adopté la Technologie, combien d'entre eux l'ont fait spontanément, à savoir sans recevoir aucune incitation matérielle, ou aucune rémunération? :

• 11-50%

Commentaires:

90% of land user families have adopted the Technology with external material support

2160 land user families have adopted the Technology with external material support

10% of land user families have adopted the Technology without any external material support

240 land user families have adopted the Technology without any external material support

There is a moderate trend towards spontaneous adoption of the Technology

Comments on adoption trend: There is a moderate trend towards spontaneous adoption.
40% of terraces have been rehabilitated in 7 districts (8 micro-watersheds) of the Colca valley.

6.7 Points forts/ avantages/ possibilités de la Technologie

6.8 Faiblesses/ inconvénients/ risques de la Technologie et moyens de les surmonter

7.1 Méthodes/ sources d'information

7.2 Références des publications disponibles

Titre, auteur, année, ISBN:

Mejia Marcacuzco AP Folleto de divulgación: Andenes, construcción y mantenimiento. (undated).

Titre, auteur, année, ISBN:

Treacy, JM (undated) LasChacras de Coporaque: Andenes y riego en el valle del Colca. Instituto de Estudios Peruanos. DESCO