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

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

2.1 Courte description de la Technologie

Définition de la Technologie:

Compacted soil bund constructed following a contour using a soil excavated from deep trenches on the up-slope side.

2.2 Description détaillée de la Technologie

Description:

Soil faced deep trench bund is constructed by excavating trenches of 1 m deep, 0.5 - 1 m wide and 2 - 3.5 m long with spacing between trenches of 0.3 - 0.5 m along the contour and using the excavated soil to construct a compacted bund downslope. The smaller dimensions are usually used in cultivated lands while the larger are implemented in grazing lands.

Purpose of the Technology: Soil faced deep trench bund decreases slope length, runoff velocity and soil loss; and increases runoff harvesting, soil moisture and groundwater recharge.

Establishment / maintenance activities and inputs: Construction of soil faced deep trench bund involves alignment of a contour, excavation of trenches, construction and compaction of bund and planting grass, while the maintenance involves dredging of sediment from the trenches and use it for reinforcing the embankment.

Line level, tape meter, digging hoe, shovel and grass are needed for the establishment and maintenance.

Natural / human environment: The technology is implemented in moderate (5 - 8%) and hill (8 - 16%) slopes and in medium and heavy soil types of at least 1 m depth. It reduces runoff amount and velocity thereby decreasing soil loss and desertification/land degradation. It also improves soil moisture availability and groundwater recharge by encouraging lateral and vertical movement of water respectively.

It is mostly constructed using communal labour and there is an encouraging trend of spontaneous adoption. The technology is witnessed to be increasing crop and fodder production thereby improving the livelihood of the land users. It, however, is labour intensive and slightly reduces farm size.

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:

Ethiopie

Région/ Etat/ Province:

Tigray

Autres spécifications du lieu:

Kilte Awlaelo

Spécifiez la diffusion de la Technologie:

• répartie uniformément sur une zone

S'il n'existe pas d'informations exactes sur la superficie, indiquez les limites approximatives de la zone couverte:

• 10-100 km2

Map

×

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

• réduire, prévenir, restaurer les terres dégradées

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

Terres cultivées

• Cultures annuelles
• Cultures pérennes (non ligneuses)

Cultures annuelles - Précisez les cultures:

• céréales - orge
• céréales - maïs
• céréales - sorgho
• cultures oléagineuses - tournesol, colza, autres

• wheat, teff

• elephant grass

Nombre de période de croissance par an: :

• 1

Précisez:

Longest growing period in days: 150 Longest growing period from month to month: June - November

Pâturages

Pâturage intensif/ production fourragère :

• Affouragement en vert/ zéro-pâturage
• Prairies améliorées

Commentaires:

Major land use problems (compiler’s opinion): Soil erosion, overgrazing, decline of soil fertility and productivity.

Major land use problems (land users’ perception): Soil erosion, reduced soil depth, fertility and productivity.

3.4 Approvisionnement en eau

Approvisionnement en eau des terres sur lesquelles est appliquée la Technologie:

• pluvial

3.5 Groupe de GDT auquel appartient la Technologie

• mesures en travers de la pente
• gestion des eaux souterraines

3.6 Mesures de GDT constituant la Technologie

pratiques végétales

• V2: Herbes et plantes herbacées pérennes

structures physiques

• S2: Diguettes, digues

Commentaires:

Main measures: structural measures

Secondary measures: vegetative measures

Type of vegetative measures: aligned: -contour

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 biologique

• Bc: réduction de la couverture végétale

Commentaires:

Main type of degradation addressed: Wt: loss of topsoil / surface erosion

Secondary types of degradation addressed: Wg: gully erosion / gullying, Bc: reduction of vegetation cover

Main causes of degradation: soil management, overgrazing, Heavy / extreme rainfall (intensity/amounts), population pressure

Secondary causes of degradation: crop management (annual, perennial, tree/shrub) (Crop residues are removed during harvesting), over-exploitation of vegetation for domestic use, change of seasonal rainfall, droughts, land tenure, poverty / wealth, education, access to knowledge and support services

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:

• réduire la dégradation des terres
• restaurer/ réhabiliter des terres sévèrement dégradées

Commentaires:

Main goals: mitigation / reduction of land degradation
Secondary goals: rehabilitation / reclamation of denuded land

4.1 Dessin technique de la Technologie

Spécifications techniques (associées au dessin technique):

Soil faced deep trench bunds are structures constructed by excavating trenches following the contour and using the excavated soil to establish compacted bund on the lower side.

Location: Tigray. Kilte Awlaelo

Date: 10/10/2014

Technical knowledge required for field staff / advisors: moderate

Technical knowledge required for land users: low

Main technical functions: control of dispersed runoff: retain / trap, reduction of slope length

Secondary technical functions: increase of infiltration, increase / maintain water stored in soil, increase of groundwater level / recharge of groundwater, sediment retention / trapping, sediment harvesting

Aligned: -contour
Vegetative material: G : grass
Number of plants per (ha): 1600
Vertical interval between rows / strips / blocks (m): 1 - 1.2
Spacing between rows / strips / blocks (m): 10 - 15
Vertical interval within rows / strips / blocks (m): 0.5

Grass species: Elephant grass is mostly planted on the bunds in a single row at spacing of 0.5 m.

Slope (which determines the spacing indicated above): 6.5 and 12%

Gradient along the rows / strips: 0%

Bund/ bank: level
Vertical interval between structures (m): 1 - 1.2
Spacing between structures (m): 10 - 15
Depth of ditches/pits/dams (m): 1
Width of ditches/pits/dams (m): 0.5 - 1
Length of ditches/pits/dams (m): 2 - 3.5
Height of bunds/banks/others (m): 0.75 - 1
Width of bunds/banks/others (m): 0.3 - 1.2
Length of bunds/banks/others (m): 60 - 100

Construction material (earth): Soil excavated from the trenches is used to construct bunds

Slope (which determines the spacing indicated above): 6.5 and 12%

Lateral gradient along the structure: 0%

Vegetation is used for stabilisation of structures.

Auteur:

Eyasu Yazew, P.O.Box 231, Mekelle University, Mekelle, Ethiopia

4.2 Informations générales sur le calcul des intrants et des coûts

autre/ monnaie nationale (précisez):

Birr

Indiquez le taux de change des USD en devise locale, le cas échéant (p.ex. 1 USD = 79.9 réal brésilien): 1 USD = :

18,0

4.3 Activités de mise en place/ d'établissement

4.4 Coûts et intrants nécessaires à la mise en place

Commentaires:

Duration of establishment phase: 48 month(s)

4.5 Activités d'entretien/ récurrentes

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

Commentaires:

Machinery/ tools: Digging hoe, shovel (Costs are included in the structural measures), Line level, tape meter, digging hoe, shovel

The cost was calculated for an average bund length and spacing of 80 m and 12.5 m respectively, which would result in a construction of 10 bunds per ha. In addition, an average trench length and spacing between trenches along the contour of 2.75 m and 0.4 m was considered respectively resulting in 25 trenches per bund and 250 trenches per ha.

The excavation of one deep trench and construction of the corresponding bund requires 3 person days during establishment while maintaining it needs 1.5 person days per year. A single row of grass is planted on the bunds at 0.5 m interval and a person is assumed to plant about 100 seedlings per day. The cost calculation rates apply to 2012. Accordingly, the price of single elephant grass is 0.4 Birr and the daily labour wage is 40 Birr for light work such as grass planting and 50 Birr for medium work such as trench excavation.

4.7 Facteurs les plus importants affectant les coûts

Décrivez les facteurs les plus importants affectant les coûts :

Labour, slope, landuse, soil depth.

5.1 Climat

5.2 Topographie

Commentaires et précisions supplémentaires sur la topographie:

Slopes on average: An average slope of 6.5% is taken for moderate slope and 12% for hill slope.

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 depth on average: The deep trench should usually be 1 m deep.
Soil texture: Medium (ranked 1) and fine/heavy (ranked 2, Appropriate in case of grazing lands.)
Soil fertility: Low (ranked 1) and medium (Clay soils in rehabilitated grazing lands, ranked 2.)
Topsoil organic matter: Low (more in cultivate lands, ranked 1) and Medium (more in grazing lands, ranked 2)
Soil drainage/infiltration is medium (ranked 1) and poor (in clay soils, ranked 2)
Soil water storage capacity is medium (ranked 1) and high (ranked 2)

5.4 Disponibilité et qualité de l'eau

5.5 Biodiversité

5.6 Caractéristiques des exploitants des terres appliquant la Technologie

Indiquez toute autre caractéristique pertinente des exploitants des terres:

Land users applying the Technology are mainly common / average land users
Population density: 100-200 persons/km2
Annual population growth: 2% - 3%
10% of the land users are rich and own 10% of the land.
60% of the land users are average wealthy and own 55% of the land (35 birr/person/day).
30% of the land users are poor and own 35% of the land.

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:

• état

Droits d’utilisation des terres:

• communautaire (organisé)
• individuel

5.9 Accès aux services et aux infrastructures

6.1 Impacts sur site que la Technologie a montrés

Impacts socio-économiques

Production

Revenus et coûts

Impacts socioculturels

Impacts écologiques

Cycle de l'eau/ ruissellement

Sols

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):

8735

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? :

• 51-90%

Commentaires:

27% of land user families have adopted the Technology with external material support

2541 land user families have adopted the Technology with external material support

73% of land user families have adopted the Technology without any external material support

6194 land user families have adopted the Technology without any external material support

There is a moderate trend towards spontaneous adoption of the Technology

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:

Staff members of the Kilte Awlaelo Wereda Office of Agriculture and Rural Development

Titre, auteur, année, ISBN:

Carucci, V. (2000). Guidelines on Water Harvesting and Soil Conservation for Moisture Deficit Areas in Ethiopia:the productive use of water and soil. First draft manual for trainers, Addis Ababa, Ethiopia.

Titre, auteur, année, ISBN:

Lakew, D., Carucci, V., Asrat, W. and Yitayew, A. (2005). Community Based Participatory Watershed Development: A guideline. Part I, first edition, Ministry of Agriculture and Rural Development, Addis Ababa, Ethiopia.