Technologies

Radical Terraces [Rwanda]

Amaterasi y'indinganire

technologies_1553 - Rwanda

Completeness: 80%

1. General information

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

Key resource person(s)

SLM specialist:
SLM specialist:
SLM specialist:
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)
FAO Food and Agriculture Organization (FAO Food and Agriculture Organization) - 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

1.5 Reference to Questionnaire(s) on SLM Approaches (documented using WOCAT)

Top down approach
approaches

Top down approach [Rwanda]

This is a top down approach to technology development and dissemination with limited involvement of intended beneficiaries.

  • Compiler: Desire Kagabo

2. Description of the SLM Technology

2.1 Short description of the Technology

Definition of the Technology:

Locally referred to as ‘radical terracing’, the method involves earth moving operations that create reverse-slope bench terraces which have properly shaped risers stabilized with grass or trees on embankment to avoid collapse.

2.2 Detailed description of the Technology

Description:

In Rwanda, a unique method of back-slope terracing originally introduced by missionaries growing wheat in the Northern Province in the 1970s, has been widely adopted by smallholder farmers in many parts of the country. The farmers are careful to isolate the topsoil, then they re-work the subsoil to create the required reverse-slope bench, after which the topsoil is spread over the surface. The riser is planted with short runner grass for stabilization, all within the same day. Radical terracing is usually done manually with hoes and shovels, mostly by communal group-work involving hundreds of farmers (see left photo). Thus, a hillside can be terraced in one day. Where radical terraces have been constructed, the effects have been dramatic, achieving optimum water and soil conservation on slopes exceeding 50%, while adoption rates have been quite extensive. This high adoption of radical terracing is related to the existing policies and programs such as land consolidation, land management and crop intensification programs. These policies/programs boost the use of radical terraces by providing farmers more opportunities to easily access inputs such as improved seeds and manure for increasing the productivity of constructed radical terraces. Recent studies (e.g. Fleskens, 2007, Bizoza and de Graaff 2012 and Kagabo et al. 2013) assert that radical terraces in the highlands of Rwanda are only financially viable when the opportunity cost of labour and manure are below the local market price levels and when agriculture area on these radical terraces can be substantially intensified. Ten to 30 metric tons of manure (organic) are required to restore the soil fertility of newly established radical terraces.

Purpose of the Technology: In Rwanda, radical terraces are principally designed (1) to reduce soil losses through enhanced retention and infiltration of runoff, (2) to promote permanent agriculture on steep slopes and (3) to promote land consolidation and intensive land use.

Establishment / maintenance activities and inputs: Newly established radical terraces should be protected at their risers and outlets, especially in the first or second year of the establishment. After establishing a terrace, a riser is shaped and grasses or shrubs/trees are planted soon after. Napier grass is commonly planted and is used as forage for livestock. Risers on radical terraces are seen as a new production niche of forage as a result of land shortage and a strict zero grazing policy.

Natural / human environment: Radical terraces have the potential of improving farmers’ livelihoods and increasing the resilience of a degraded environment.

2.3 Photos of the Technology

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

Country:

Rwanda

Region/ State/ Province:

Rwanda

Further specification of location:

Kayonza District (Eastern province)

Specify the spread of the Technology:
  • evenly spread over an area
If the Technology is evenly spread over an area, specify area covered (in km2):

10.3

Comments:

Total area covered by the SLM Technology is 10.3 km2.

2.6 Date of implementation

If precise year is not known, indicate approximate date:
  • less than 10 years ago (recently)

2.7 Introduction of the Technology

  • Government
Comments (type of project, etc.):

The Government introduced it through local leaders and agronomist. It was established in 2004

3. Classification of the SLM Technology

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

Cropland

Cropland

  • Annual cropping
  • Perennial (non-woody) cropping
Annual cropping - Specify crops:
  • root/tuber crops - sweet potatoes, yams, taro/cocoyam, other
Perennial (non-woody) cropping - Specify crops:
  • pineapple
Number of growing seasons per year:
  • 2
Specify:

Longest growing period in days: 120; Longest growing period from month to month: September- January; Second longest growing period in days: 90; Second longest growing period from month to month: March - June

Comments:

Major cash crop: Sweet potato and pineapple

Major land use problems (compiler’s opinion): Soil erosion due to high runoff on the steep slopes, deforestation, intensive cultivation and lack of suitable land management methods.

Major land use problems (land users’ perception): Low crop production, soil erosion and lack of fodder

3.4 Water supply

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

3.5 SLM group to which the Technology belongs

  • cross-slope measure

3.6 SLM measures comprising the Technology

vegetative measures

vegetative measures

  • V2: Grasses and perennial herbaceous plants
structural measures

structural measures

  • S1: Terraces
Comments:

Type of vegetative measures: aligned: -contour

3.7 Main types of land degradation addressed by the Technology

soil erosion by water

soil erosion by water

  • Wt: loss of topsoil/ surface erosion
  • Wo: offsite degradation effects
Comments:

Secondary types of degradation addressed: Wo: offsite degradation effects

Main causes of degradation: over-exploitation of vegetation for domestic use, overgrazing (Grazing and fodder), other natural causes (avalanches, volcanic eruptions, mud flows, highly susceptible natural resources, extreme topography, etc.) specify (Extreme topography: steep slopes in many cases over 50%), population pressure (High density (in rural area over 400 inhabitant per ha))

Secondary causes of degradation: deforestation / removal of natural vegetation (incl. forest fires) (Use of cooking energy (fire wood)), 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:
  • reduce land degradation
Comments:

Secondary goals: prevention of land degradation, rehabilitation / reclamation of denuded land

4. Technical specifications, implementation activities, inputs, and costs

4.1 Technical drawing of the Technology

Technical specifications (related to technical drawing):

The farmers are careful to isolate the topsoil, then they re-work the subsoil to create the required reverse-slope bench, after which the topsoil is spread over the surface. The riser is planted with short runner grass for stabilization, all within the same period.

Location: Nyamirama. Kayonza/West/Rwanda

Date: 2013

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

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

Main technical functions: control of concentrated runoff: retain / trap

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

Aligned: -contour
Vegetative material: G : grass
Number of plants per (ha): 2000
Vertical interval between rows / strips / blocks (m): 1
Spacing between rows / strips / blocks (m): 4
Vertical interval within rows / strips / blocks (m): 0.2
Width within rows / strips / blocks (m): 0.2

Grass species: Pennisetum

Slope (which determines the spacing indicated above): 35%

If the original slope has changed as a result of the Technology, the slope today is (see figure below): 0%

Gradient along the rows / strips: 0%

Terrace: bench level
Vertical interval between structures (m): 2
Spacing between structures (m): 4

Slope (which determines the spacing indicated above): 20-50%

If the original slope has changed as a result of the Technology, the slope today is: 0%

Lateral gradient along the structure: 0%

Vegetation is used for stabilisation of structures.

Author:

Kagabo Desire and Ngenzi Guy, RAB, 5016 Kigali

4.2 General information regarding the calculation of inputs and costs

other/ national currency (specify):

Rwandan francs

If relevant, indicate exchange rate from USD to local currency (e.g. 1 USD = 79.9 Brazilian Real): 1 USD =:

640.0

Indicate average wage cost of hired labour per day:

1000

4.3 Establishment activities

Activity Timing (season)
1. Cuttings of grasses Rain season
2. Transport of grass cuttings Rain season
3. Planting of grass cuttings Rain season
4. Land surveying (slope determination, soil structure and texture analysis) any time
5. Construction of bunds (risers) with soil from upper and lower sides dry season
6. Level terraces bed (surface soil moved from upper to lower part of terraces) dry season
7. cutting subsurface soil, leveling and refilling surface soil dry season
8. Make lips on edges of terraces dry season
9. Compact risers dry season
10. Plant grasses including agro-forestery trees. rainy season
11. Input/ application of farmyard manure and liming rainy season

4.4 Costs and inputs needed for establishment

Specify input Unit Quantity Costs per Unit Total costs per input % of costs borne by land users
Labour Cuttings of grasses persons/day/ha 2.0 1000.0 2000.0 60.0
Labour Transport of grass cuttings persons/day/ha 10.0 1000.0 10000.0
Labour Planting of grass cuttings persons/day/ha 20.0 1000.0 20000.0 100.0
Labour Land surveying (slope determination, soil structure and texture persons/day/ha 6.0 20000.0 120000.0
Fertilizers and biocides Lime kg/ha 2500.0 40.0 100000.0
Fertilizers and biocides Famyard manure kg/ha 30000.0 5.0 150000.0
Fertilizers and biocides Mineral fertilizers kg/ha 300.0 500.0 150000.0
Other Labour: Construction of bunds persons/day/ha 100.0 1000.0 100000.0
Other Labour: Level terraces bed persons/day/ha 250.0 1000.0 250000.0
Other Labour: Cutting subsurface soil persons/day/ha 250.0 1000.0 250000.0
Other Labour: Make lips on edges of terraces persons/day/ha 10.0 1000.0 10000.0
Other Labour: Compact risers persons/day/ha 50.0 1000.0 50000.0
Other Labour: Plant grasses including agro-forestery trees persons/day/ha 50.0 1000.0 50000.0
Total costs for establishment of the Technology 1262000.0
Total costs for establishment of the Technology in USD 1971.88
Comments:

Duration of establishment phase: 1 month(s)

4.5 Maintenance/ recurrent activities

Activity Timing/ frequency
1. Weeding Before crop planting/each cropping season
2. Manure application Before crop planting/annually
3. Grass streaming Throughout the year
4. Cleaning of channels and drains through out the year
5. Regular repair of destroyed risers through the year

4.6 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 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 Cleaning of channels and drains persons/day/ha 10.0 300.0 3000.0 100.0
Other Labour: Regular repair of destroyed risers persons/day/ha 6.0 333.3333 2000.0 100.0
Total costs for maintenance of the Technology 22000.0
Total costs for maintenance of the Technology in USD 34.38
Comments:

Machinery/ tools: Small hoes and machete, Hoes, machete, spade, A.fram, macako and meters.

The cost is calculated using the rate of US dollars at present time and were estimated according to the cost of construction of one radical terrace. At present the labor is 1.6$ per day. This was calculated on 25/07/2011.

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

Factors that affect the cost are labor, soil structure and slope

5. Natural and human environment

5.1 Climate

Annual rainfall
  • < 250 mm
  • 251-500 mm
  • 501-750 mm
  • 751-1,000 mm
  • 1,001-1,500 mm
  • 1,501-2,000 mm
  • 2,001-3,000 mm
  • 3,001-4,000 mm
  • > 4,000 mm
Specifications/ comments on rainfall:

1000-1500 mm: September - December

1500-2000 mm: February - June

Agro-climatic zone
  • sub-humid

Thermal climate class: tropics. All months are above 18 degree C.

5.2 Topography

Slopes on average:
  • flat (0-2%)
  • gentle (3-5%)
  • moderate (6-10%)
  • rolling (11-15%)
  • hilly (16-30%)
  • steep (31-60%)
  • very steep (>60%)
Landforms:
  • plateau/plains
  • ridges
  • mountain slopes
  • hill slopes
  • footslopes
  • valley floors
Altitudinal zone:
  • 0-100 m a.s.l.
  • 101-500 m a.s.l.
  • 501-1,000 m a.s.l.
  • 1,001-1,500 m a.s.l.
  • 1,501-2,000 m a.s.l.
  • 2,001-2,500 m a.s.l.
  • 2,501-3,000 m a.s.l.
  • 3,001-4,000 m a.s.l.
  • > 4,000 m a.s.l.

5.3 Soils

Soil depth on average:
  • very shallow (0-20 cm)
  • shallow (21-50 cm)
  • moderately deep (51-80 cm)
  • deep (81-120 cm)
  • very deep (> 120 cm)
Soil texture (topsoil):
  • coarse/ light (sandy)
  • medium (loamy, silty)
Topsoil organic matter:
  • low (<1%)
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 low

Soil drainage / infiltration is good

Soil water storage capacity is low - medium

5.4 Water availability and quality

Ground water table:

> 50 m

Availability of surface water:

poor/ none

Water quality (untreated):

poor drinking water (treatment required)

Comments and further specifications on water quality and quantity:

Water quality (untreated): Good drinking water available but very far to fetch.

5.5 Biodiversity

Species diversity:
  • low

5.6 Characteristics of land users applying the Technology

Market orientation of production system:
  • subsistence (self-supply)
  • commercial/ market
Off-farm income:
  • less than 10% of all income
Relative level of wealth:
  • very poor
  • poor
Individuals or groups:
  • individual/ household
Level of mechanization:
  • manual work
Gender:
  • women
  • men
Indicate other relevant characteristics of the land users:

Population density: 50-100 persons/km2

Annual population growth: 2% - 3%

75% of the land users are poor and own 60% of the land.
25% of the land users are poor and own 40% of the land.

5.7 Average area of land used by land users applying the Technology

  • < 0.5 ha
  • 0.5-1 ha
  • 1-2 ha
  • 2-5 ha
  • 5-15 ha
  • 15-50 ha
  • 50-100 ha
  • 100-500 ha
  • 500-1,000 ha
  • 1,000-10,000 ha
  • > 10,000 ha
Is this considered small-, medium- or large-scale (referring to local context)?
  • small-scale

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

Land ownership:
  • individual, not titled
  • individual, titled
Land use rights:
  • individual
Water use rights:
  • open access (unorganized)
  • communal (organized)

5.9 Access to services and infrastructure

health:
  • poor
  • moderate
  • good
education:
  • poor
  • moderate
  • good
technical assistance:
  • poor
  • moderate
  • good
employment (e.g. off-farm):
  • poor
  • moderate
  • good
markets:
  • poor
  • moderate
  • good
energy:
  • poor
  • moderate
  • good
roads and transport:
  • poor
  • moderate
  • good
drinking water and sanitation:
  • poor
  • moderate
  • good
financial services:
  • poor
  • moderate
  • good

6. Impacts and concluding statements

6.1 On-site impacts the Technology has shown

Socio-economic impacts

Production

crop production

decreased
increased

fodder production

decreased
increased

production area

decreased
increased
Comments/ specify:

Reduce crop area

Income and costs

expenses on agricultural inputs

increased
decreased
Comments/ specify:

Require high quantity of FYM and mineral fertilizers

Socio-cultural impacts

food security/ self-sufficiency

reduced
improved

SLM/ land degradation knowledge

reduced
improved

livelihood and human well-being

reduced
improved
Comments/ specify:

The technology is newly established and the soil need enough farmyard manure and inputs to re-stabilize and regain its fertility

Ecological impacts

Water cycle/ runoff

water quantity

decreased
increased

surface runoff

increased
decreased
Soil

soil moisture

decreased
increased

soil loss

increased
decreased
Climate and disaster risk reduction

impacts of cyclones, rain storms

increased
decreased

emission of carbon and greenhouse gases

increased
decreased
Other ecological impacts

disturbance of fertile top soil

increased
decreased

biodiversity

diminished
enhanced

6.2 Off-site impacts the Technology has shown

downstream flooding

increased
reduced

downstream siltation

increased
decreased

damage on neighbours' fields

increased
reduced

damage on public/ private infrastructure

increased
reduced

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 increase or decrease 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
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 not known
land slides not well

6.4 Cost-benefit analysis

How do the benefits compare with the establishment costs (from land users’ perspective)?
Short-term returns:

negative

Long-term returns:

very positive

How do the benefits compare with the maintenance/ recurrent costs (from land users' perspective)?
Short-term returns:

very negative

Long-term returns:

neutral/ balanced

6.5 Adoption of the Technology

  • > 50%
If available, quantify (no. of households and/ or area covered):

150 households covering 75 percent of stated area

Of all those who have adopted the Technology, how many did so spontaneously, i.e. without receiving any material incentives/ payments?
  • 0-10%
Comments:

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

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

There is a little trend towards spontaneous adoption of the Technology

Comments on adoption trend: The real advantages of the technology are observed after 5 to 6 years with good maintenance of structures

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
It reduces soil runoff

How can they be sustained / enhanced? Good maintenance of structures
Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
It controls soil erosion

How can they be sustained / enhanced? There is a need to plant grasses or trees on risers to stabilize terraces
It increases soil water holding capacity

How can they be sustained / enhanced? Organic manure should be added to the terrace to effectively increase the soil water holding capacity.
It increases fodder availability as new niches for fodder production are created.

How can they be sustained / enhanced? High value nutritive fodder should be planted (napier grass, calliadra, tripsucum, etc.) on risers
It increases crop productivity

How can they be sustained / enhanced? Terraces should be well maintained by providing more inputs and regular maintenance of bench struactures

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 reduces the cropped land Farmers should be supported in accessing high value crops and inputs to maximize crop yield.
Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view How can they be overcome?
The establishment of radical terraces is expensive The construction of radical terraces should be subsided by the government.
The initial soil structure is disturbed (lost of soil organic matter) Heavy investments are needed to replenish the soil fertility, especially by adding organic manure.
The establishment of radical terraces decreases cropped land. Grow high value crops and use adequate quantity of inputs.
With poor maintenance or poor design of radical terraces, landslides may occur. To be much more rigorous in the design and implementation/development of terraces by making sure that professionals are involved in the whole process of establishing terraces.

7. References and links

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/

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