1.2 Contact details of resource persons and institutions involved in the assessment and documentation of the Technology

Name of project which facilitated the documentation/ evaluation of the Technology (if relevant)

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

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)

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

Name of the institution(s) which facilitated the documentation/ evaluation of the Technology (if relevant)

Rwanda Agriculture Board (Rwanda Agriculture Board) - Rwanda

1.3 Conditions regarding the use of data documented through WOCAT

The compiler and key resource person(s) accept the conditions regarding the use of data documented through WOCAT:

Yes

2.1 Short description of the Technology

Definition of the Technology:

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 Detailed description of the Technology

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 of the Technology

2.5 Country/ region/ locations where the Technology has been applied and which are covered by this assessment

2.6 Date of implementation

If precise year is not known, indicate approximate date:

• 10-50 years ago

2.7 Introduction of the Technology

• Government

3.1 Main purpose(s) of the Technology

• reduce, prevent, restore land degradation

3.2 Current land use type(s) where the Technology is applied

Comments:

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

If land use has changed due to the implementation of the Technology, indicate land use before implementation of the Technology:

Grazing land: Ge: Extensive grazing land

3.3 Further information about land use

Water supply for the land on which the Technology is applied:

• rainfed

Specify:

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

Livestock density (if relevant):

10-25 LU /km2

3.4 SLM group to which the Technology belongs

• improved ground/ vegetation cover
• cross-slope measure

3.5 Spread of the Technology

Specify the spread of the Technology:

• evenly spread over an area

If the Technology is evenly spread over an area, indicate approximate area covered:

• 10-100 km2

Comments:

The area covered by this technology has been estimated

3.6 SLM measures comprising the Technology

Comments:

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

3.7 Main types of land degradation addressed by the Technology

Comments:

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 Prevention, reduction, or restoration of land degradation

Specify the goal of the Technology with regard to land degradation:

• prevent land degradation
• reduce land degradation

Comments:

Secondary goals: prevention of land degradation

4.1 Technical drawing of the Technology

4.2 Technical specifications/ explanations of technical drawing

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 General information regarding the calculation of inputs and costs

other/ national currency (specify):

Rwandan Francs

Indicate exchange rate from USD to local currency (if relevant): 1 USD =:

640.0

4.4 Establishment activities

	Activity	Type of measure	Timing
1.	Cuttings	Vegetative	Rainy season
2.	Transport	Vegetative	Rainy season
3.	Planting	Vegetative	Rainy season
4.	Identification of contour lines, digging of trenches and grass planting on risers	Structural	dry season

4.5 Costs and inputs needed for establishment

	Specify input	Unit	Quantity	Costs per Unit	Total costs per input	% of costs borne by land users
Labour	Planting	persons/day/ha	20.0	1000.0	20000.0	100.0
Labour	Identification of contour lines, digging and planting	persons/day/ha	100.0	1000.0	100000.0	100.0
Equipment	Transport	ha	10.0	1000.0	10000.0	100.0
Equipment	Tools	pieces/ha	100.0	1200.0	120000.0	100.0
Plant material	Cuttings	ha	2.0	1000.0	2000.0	100.0
Total costs for establishment of the Technology					252000.0

Comments:

Duration of establishment phase: 1 month(s)

4.6 Maintenance/ recurrent activities

	Activity	Type of measure	Timing/ frequency
1.	Weeding	Vegetative	Before crop planting/each cropping season
2.	Manure application and transportation	Vegetative	Before crop planting/annually
3.	Grass streaming	Vegetative	Throughout the year
4.	Clearing the ditches by removing piled up sediments.	Structural	Rainy season

4.7 Costs and inputs needed for maintenance/ recurrent activities (per year)

	Specify input	Unit	Quantity	Costs per Unit	Total costs per input	% of costs borne by land users
Labour	Weeding	persons/day/ha	5.0	1000.0	5000.0	100.0
Labour	Manure application and transportation	persons/day/ha	10.0	1000.0	10000.0	100.0
Labour	Grass streaming	persons/day/ha	2.0	1000.0	2000.0	100.0
Labour	Clearing the ditches	persons/day/ha	30.0	1000.0	30000.0	100.0
Equipment	Tools	pieces/ha	30.0	800.0	24000.0	100.0
Total costs for maintenance of the Technology					71000.0

Comments:

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 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

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 Climate

5.2 Topography

5.3 Soils

If available, attach full soil description or specify the available information, e.g. soil type, soil PH/ acidity, Cation Exchange Capacity, nitrogen, salinity etc.

Soil fertility is medium

Soil drainage / infiltration is good

Soil water storage capacity is medium

5.4 Water availability and quality

5.5 Biodiversity

5.6 Characteristics of land users applying the Technology

Indicate other relevant characteristics of the land users:

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 Average area of land owned or leased by land users applying the Technology

5.8 Land ownership, land use rights, and water use rights

Land ownership:

• individual, titled

Land use rights:

• individual

Water use rights:

• open access (unorganized)

5.9 Access to services and infrastructure

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

Income and costs

Socio-cultural impacts

Ecological impacts

Water cycle/ runoff

Soil

Other ecological impacts

6.2 Off-site impacts the Technology has shown

6.3 Exposure and sensitivity of the Technology to gradual climate change and climate-related extremes/ disasters (as perceived by land users)

Gradual climate change

Gradual climate change

	Season	Type of climatic change/ extreme	How does the Technology cope with it?
annual temperature		increase	well

Climate-related extremes (disasters)

Meteorological disasters

	How does the Technology cope with it?
local rainstorm	not well
local windstorm	well

Climatological disasters

	How does the Technology cope with it?
drought	well

Hydrological disasters

	How does the Technology cope with it?
general (river) flood	not well

Other climate-related consequences

Other climate-related consequences

	How does the Technology cope with it?
reduced growing period	well

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?

6.5 Adoption of the Technology

• more than 50%

If available, quantify (no. of households and/ or area covered):

207 households covering 100 percent of the stated area

Of all those who have adopted the Technology, how many have did so spontaneously, i.e. without receiving any material incentives/ payments?

• 90-100%

Comments:

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 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
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

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
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 Weaknesses/ disadvantages/ risks of the Technology and ways of overcoming them

Weaknesses/ disadvantages/ risks in the land user’s view	How can they be overcome?
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

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view	How can they be overcome?
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 References to available publications

Title, author, year, ISBN:

Kagera TAMP project website

Available from where? Costs?

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

Title, author, year, ISBN:

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

Available from where? Costs?

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