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)

The Transboundary Agro-ecosystem Management Project for the Kagera River Basin (GEF-FAO / Kagera TAMP )

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

Food and Agriculture Organization of the United Nations (FAO) - Italie

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

Rwanda Agriculture Board (Rwanda Agriculture Board) - Rwanda

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:

Trenches combined with living hedges or grass lines are slow-forming terraces to control soil erosion by changing the length of the slope and progressively reducing the slope gradient; he slope steepness decreases progressively by hydric and tillage erosion.

2.2 Description détaillée de la Technologie

Description:

Trenches combined with living hedges or grassed lines are less labour-intensive method that is practiced in the highlands of Rwanda. The method involves digging trenches which have grass-stabilized banks, or simply planting grass strips and vegetative barriers across the slope to reduce runoff. This method, locally referred to as ‘progressive terracing’, is more adaptable by individual farmers across the country. In the study conducted by Kagabo et al. (2013) in the highlands of Buberuka Region of Rwanda, it was noted that net increment in yields and returns on investment increased with the age of terraces, since the capital costs of terracing were easily recovered. These terraces also showed more resilience, some being over 30 years old and still effective. Along the contour band, soil from the upper parts of the slope is removed and deposited above by creating a series of discontinuous trenches in order to extend the flat terrain. Over 5-10 years, the terraces become enlarged and form a terrace along the contour, such that the slopes are transformed over time into level bench terraces (but never %).

Purpose of the Technology: The main purpose of this technology is to reduce runoff and soil erosion on the slope and to improve soil quality and soil moisture retention. Grass strips or living hedgerows are intended to both trap sediments and facilitate the slow formation of terraces.

Establishment / maintenance activities and inputs: The establishment of trenches combined with living hedges or grassed lines is less labor intensive and requires less skilled labor. Regular maintenance banks on which living hedges are planted, to seasonally stream living hedges to minimize the competition of nutrients and water with plants. To efficiently use these terraces it is advisable to introduce intensive and rentable cropping systems or agroforestry with fruits and forage trees.

Natural / human environment: This technology was reported to be very resilient as trenches combined with living hedges or grassed lines of 20+ year old are still effective in controlling soil erosion. However, the soil quality on these formed terraces between alleys does not homogenize 100% over the course of time. Large soil fertility gradients with marked spatial difference in both soil quality and crop yield from their upper parts downwards of the terraces is observed. The soil in the lower parts of the terraces showed as much as 57% more organic carbon content and 31% more available phosphorous than the soil in the upper parts of the terraces (Kagabo et al. 2013).

2.3 Photos de la Technologie

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

2.6 Date de mise en œuvre de la Technologie

Si l'année précise est inconnue, indiquez la date approximative: :

• il y a entre 10-50 ans

2.7 Introduction de la Technologie

• Government

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

Commentaires:

Major land use problems (compiler’s opinion): Soil erosion, water contamination due to sediment loads, decrease of soil fertility and soil depth, loss of vegetation cover

Major land use problems (land users’ perception): Soil erosion, contamination of water (the turbidity of water is high) therefore the domestic use of water is a problem.

Future (final) land use (after implementation of SLM Technology): Cropland: Ca: Annual cropping

Si l'utilisation des terres a changé en raison de la mise en œuvre de la Technologie, indiquez l'utilisation des terres avant la mise en œuvre de la Technologie:

Grazing land: Ge: Extensive grazing land

3.3 Informations complémentaires sur l'utilisation des terres

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

• pluvial

Précisez:

Longest growing period in days: 150; Longest growing period from month to month: September – February; Second longest growing period in days: 120; Second longest growing period from month to month: March – July

Densité d'élevage/ chargement (si pertinent):

10-25 LU /km2

3.4 Groupe de GDT auquel appartient la Technologie

• Amélioration de la couverture végétale/ du sol
• mesures en travers de la pente

3.5 Diffusion de la Technologie

Spécifiez la diffusion de la Technologie:

• répartie uniformément sur une zone

Si la Technologie est uniformément répartie sur une zone, indiquez la superficie couverte approximative:

• 10-100 km2

Commentaires:

The area covered by this technology has been estimated

3.6 Mesures de GDT constituant la Technologie

Commentaires:

Type of vegetative measures: aligned: -contour, aligned: -along boundary

3.7 Principaux types de dégradation des terres traités par la Technologie

Commentaires:

Secondary types of degradation addressed: Wg: gully erosion / gullying, Wo: offsite degradation effects

Main causes of degradation: deforestation / removal of natural vegetation (incl. forest fires) (Used as energy (fire wood)), other natural causes (avalanches, volcanic eruptions, mud flows, highly susceptible natural resources, extreme topography, etc.) specify (Steep slopes in many cases are over 60%), population pressure (High density (in rural area over 400 inhabitant per ha))

Secondary causes of degradation: soil management (Less use of organic manure), crop management (annual, perennial, tree/shrub) (No proper crop rotation and all crop residues are exported), over-exploitation of vegetation for domestic use (Fodder), poverty / wealth (Farmers have low income and have less access to off farm income or remittances), education, access to knowledge and support services (High rate of irriteracy)

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:

• prévenir la dégradation des terres
• réduire la dégradation des terres

Commentaires:

Secondary goals: prevention of land degradation

4.1 Dessin technique de la Technologie

4.2 Spécification/ explications techniques du dessin technique

Trenches are dug in trapezoidal shape with 40 cm of height, 30 cm of base length and 50 cm of top lengths. An empty space of 40 cm is left between two consecutive trenches along a contour line.

Location: Kamonyi/Giko. Southern province

Date: 2012

Technical knowledge required for field staff / advisors: high (Special training should be provided to field staff to be able to make an adequate design and teach land users)

Technical knowledge required for land users: low (Land users are required to only implement the technology under the supervision of field staff)

Technical knowledge required for Farmer representive: high (These farmers need to be trained so that the can easily supervise the work)

Main technical functions: control of concentrated runoff: retain / trap, reduction of slope length, improvement of topsoil structure (compaction), increase of infiltration, sediment retention / trapping, sediment harvesting

Secondary technical functions: control of concentrated runoff: impede / retard, reduction of slope angle

Aligned: -contour
Vegetative material: G : grass
Number of plants per (ha): 11114
Vertical interval between rows / strips / blocks (m): 1
Spacing between rows / strips / blocks (m): 6
Vertical interval within rows / strips / blocks (m): 0.3
Width within rows / strips / blocks (m): 0.2

Aligned: -along boundary
Vegetative material: T : trees / shrubs, F : fruit trees / shrubs, G : grass
Number of plants per (ha): 84
Vertical interval between rows / strips / blocks (m): NA
Spacing between rows / strips / blocks (m): NA
Vertical interval within rows / strips / blocks (m): 20
Width within rows / strips / blocks (m): NA

Trees/ shrubs species: Grevelea/planted

Fruit trees / shrubs species: Avocado/Planted

Grass species: Napier grass/planted

Slope (which determines the spacing indicated above): 20%

If the original slope has changed as a result of the Technology, the slope today is (see figure below): 45%

Gradient along the rows / strips: 0%

Bund/ bank: level
Vertical interval between structures (m): 1.2
Spacing between structures (m): 6
Depth of ditches/pits/dams (m): 0.4
Width of ditches/pits/dams (m): 0.5
Length of ditches/pits/dams (m): 5
Height of bunds/banks/others (m): 0.4
Width of bunds/banks/others (m): 0.4
Length of bunds/banks/others (m): 5

Bund/ bank: graded
Vertical interval between structures (m): 1.2
Spacing between structures (m): 6
Depth of ditches/pits/dams (m): 0.4
Width of ditches/pits/dams (m): 0.5
Length of ditches/pits/dams (m): 5
Height of bunds/banks/others (m): 0.4
Width of bunds/banks/others (m): 0.4
Length of bunds/banks/others (m): 5

Construction material (earth): Soil excavation in farmers land along the contour

Slope (which determines the spacing indicated above): 30%

If the original slope has changed as a result of the Technology, the slope today is: 10%

Lateral gradient along the structure: 0%

Vegetation is used for stabilisation of structures.

4.3 Informations générales sur le calcul des intrants et des coûts

autre/ monnaie nationale (précisez):

Rwandan Francs

Indiquer le taux de change du dollars en monnaie locale (si pertinent): 1 USD= :

640,0

4.4 Activités de mise en place/ d'établissement

	Activité	Type de mesures	Calendrier
1.	Cuttings	Végétale	Rainy season
2.	Transport	Végétale	Rainy season
3.	Planting	Végétale	Rainy season
4.	Identification of contour lines, digging of trenches and grass planting on risers	Structurel	dry season

4.5 Coûts et intrants nécessaires à la mise en place

	Spécifiez les intrants	Unité	Quantité	Coûts par unité	Coût total par intrant	% des coût supporté par les exploitants des terres
Main d'œuvre	Planting	persons/day/ha	20,0	1000,0	20000,0	100,0
Main d'œuvre	Identification of contour lines, digging and planting	persons/day/ha	100,0	1000,0	100000,0	100,0
Equipements	Transport	ha	10,0	1000,0	10000,0	100,0
Equipements	Tools	pieces/ha	100,0	1200,0	120000,0	100,0
Matériel végétal	Cuttings	ha	2,0	1000,0	2000,0	100,0
Coût total de mise en place de la Technologie					252000,0

Commentaires:

Duration of establishment phase: 1 month(s)

4.6 Activités d'entretien/ récurrentes

	Activité	Type de mesures	Calendrier/ fréquence
1.	Weeding	Végétale	Before crop planting/each cropping season
2.	Manure application and transportation	Végétale	Before crop planting/annually
3.	Grass streaming	Végétale	Throughout the year
4.	Clearing the ditches by removing piled up sediments.	Structurel	Rainy season

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

	Spécifiez les intrants	Unité	Quantité	Coûts par unité	Coût total par intrant	% des coût supporté par les exploitants des terres
Main d'œuvre	Weeding	persons/day/ha	5,0	1000,0	5000,0	100,0
Main d'œuvre	Manure application and transportation	persons/day/ha	10,0	1000,0	10000,0	100,0
Main d'œuvre	Grass streaming	persons/day/ha	2,0	1000,0	2000,0	100,0
Main d'œuvre	Clearing the ditches	persons/day/ha	30,0	1000,0	30000,0	100,0
Equipements	Tools	pieces/ha	30,0	800,0	24000,0	100,0
Coût total d'entretien de la Technologie					71000,0

Commentaires:

Machinery/ tools: Not applicable

The cost of labor is estimated based on land steepness, soil structure (deep, gravel or shallow soils). Land steepness defines the spacing between anti-erosion ditches hence affecting the cost of labor. Similarly, the soil structure (deep, gravel or shallow soils) defines the size of labor to be used per hectare.

4.8 Facteurs les plus importants affectant les coûts

Décrivez les facteurs les plus importants affectant les coûts :

The most determining factor affecting the cost is labor (the cost of labor increases with the nature of the soil structure as well as with the land steepness.

5.1 Climat

5.2 Topographie

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 is medium

Soil drainage / infiltration is good

Soil water storage capacity is medium

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: 50-100 persons/km2

Annual population growth: 2% - 3%; 3%

75% of the land users are poor and own 75% of the land.
30% of the land users are poor and own 25% of the land.

5.7 Superficie moyenne des terres détenues ou louées par les exploitants appliquant la Technologie

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

Propriété foncière:

• individu, avec titre de propriété

Droits d’utilisation des terres:

• individuel

Droits d’utilisation de l’eau:

• accès libre (non organisé)

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

Autres impacts écologiques

6.2 Impacts hors site que la Technologie a montrés

6.3 Exposition et sensibilité de la Technologie aux changements progressifs et aux évènements extrêmes/catastrophes liés au climat (telles que perçues par les exploitants des terres)

Changements climatiques progressifs

Changements climatiques progressifs

	Saison	Type de changements/ extrêmes climatiques	Comment la Technologie fait-elle face à cela?
températures annuelles		augmente	bien

Extrêmes climatiques (catastrophes)

Catastrophes météorologiques

	Comment la Technologie fait-elle face à cela?
pluie torrentielle locale	pas bien
tempête de vent locale	bien

Catastrophes climatiques

	Comment la Technologie fait-elle face à cela?
sécheresse	bien

Catastrophes hydrologiques

	Comment la Technologie fait-elle face à cela?
inondation générale (rivière)	pas bien

Autres conséquences liées au climat

Autres conséquences liées au climat

	Comment la Technologie fait-elle face à cela?
réduction de la période de croissance	bien

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

• plus de 50%

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

207 households covering 100 percent of the stated area

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

• 90-100%

Commentaires:

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

There is a strong trend towards spontaneous adoption of the Technology

Comments on adoption trend: 100% of farmers has adopted the technology

6.7 Points forts/ avantages/ possibilités de la Technologie

Points forts/ avantages/ possibilités du point de vue de l'exploitant des terres
To prevent soil erosion How can they be sustained / enhanced? Maintenance of contour lines
Grasses provide mulching How can they be sustained / enhanced? Proper maintenance of grasses on contour lines

Points forts/ avantages/ possibilités du point de vue du compilateur ou d'une autre personne ressource clé
Mitigation of land degradation due to soil erosion How can they be sustained / enhanced? Continuous sensitization and enforcement by government to land users to stabilize the technology.
Increased crop productivity How can they be sustained / enhanced? Continuous training from government and give all basic necessary support services to land users
Increased fodder production How can they be sustained / enhanced? Proper maintenance of the technology by land users

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

Faiblesses/ inconvénients/ risques du point de vue de l’exploitant des terres	Comment peuvent-ils être surmontés?
It is hard to implement mainly by older and poor land users	It is required to offer communal support or financial support from development partners

Faiblesses/ inconvénients/ risques du point de vue du compilateur ou d'une autre personne ressource clé	Comment peuvent-ils être surmontés?
It requires a lot of physical energy, elderly people can't afford	Help each other through communal work (umuganda)
Labor costs	Land users with less financial means should join their efforts by working together

7.2 Références des publications disponibles

Titre, auteur, année, ISBN:

Kagera TAMP project website

Disponible à partir d'où? Coût?

http://www.fao.org/nr/kagera/en/

Titre, auteur, année, ISBN:

Participatory Integrated Watershed Managementin the north-western highlands of RwandaMbarushimana Désiré2013

Disponible à partir d'où? Coût?

http://www.wageningenur.nl/nl/show/Desire-Kagabo-Participatory-Integrated-Watershed-Management-in-the-northwestern-highlands-of-Rwanda.htm