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)

Book project: where the land is greener - Case Studies and Analysis of Soil and Water Conservation Initiatives Worldwide (where the land is greener)

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

Book project: SLM in Practice - Guidelines and Best Practices for Sub-Saharan Africa (SLM in Practice)

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

Ministry of Agriculture, Livestock and Fisheries (MoA) - Kenya

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)

2.1 Short description of the Technology

Definition of the Technology:

Multipurpose Grevillea robusta trees planted along farm boundaries, on terrace risers and occasionally scattered in cropland.

2.2 Detailed description of the Technology

Description:

While Grevillea robusta (the ‘silky oak’, an Australian native tree) was originally introduced from India to East Africa as a shade tree for tea and coffee estates, it is now more commonly associated with small-scale farming areas. There are three main forms of grevillea agroforestry systems: (1) most commonly trees are planted along farm boundaries, initially at a close spacing (0.75-1 m), then later thinned to 1.5-3 m, giving approximately 400 plants/ha; (2) scattered grevillea trees associated with annual or perennial crops: resembling open forests with multi-storey layers; (3) grevillea is sometimes grown in a form of ‘alley cropping’ on terraces, with 4–8 m interval between the rows and a spacing of 3-5 m within the rows.
Grevillea is primarily used in combination with annual (maize/beans) and perennial crops (coffee). It can be easily propagated and established and is relatively free of pests and diseases. Trees are managed through periodic pollarding - the pruning of side branches (for use) while maintaining the trunk. This gives the visual impression of ‘telegraph poles’, but competition with crops (which is little, in any case) is reduced and pruned branches rapidly regrow. An additional measure for avoiding competition with crops is to dig a small trench around the trees, thus cutting the superficial roots.
Grevillea is planted for a number of purposes. These include marking property boundaries, supplying fuelwood and building materials, providing shade and for ornamental value. Simultaneously it can control raindrop splash (when an understorey of litter builds up beneath), increases organic matter, and provides mulching materials to improve ground cover in the farm. Grevillea reduces wind speed, and encourages nutrient recycling due to its deep rooting.
While the climate in the case study area is subhumid, and the slopes moderate to steep with soils of medium erodibility, grevillea can be planted over a wide range of agroecological zones - from semi-arid to humid zones, and from sea level up to 2,000 metres and higher. It is ideally suited to intensive areas of small-scale mixed farming, where grevillea is valued primarily for the supply of products (fuel and construction wood in particular) to meet various household needs: it is not mainly targeted at soil erosion control though this is achieved in various ways as explained above. To effectively combat soil erosion problems on slopes, grevillea planting must be combined with additional measures such as fanya juu and bench terraces, grass strips and other vegetative and agronomic forms of conservation.

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:

• more than 50 years ago (traditional)

2.7 Introduction of the Technology

Specify how the Technology was introduced:

• as part of a traditional system (> 50 years)

Comments (type of project, etc.):

Trees initially sourced from nurseries

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

Land use mixed within the same land unit:

Yes

Specify mixed land use (crops/ grazing/ trees):

• Agroforestry

Comments:

Main products/ services: grevillea trees, maize/beans, coffee, macadamia and banana

Major land use problems (compiler’s opinion): - land degradation, mainly by water erosion
- soil fertility decline due to continuous cropping and few inputs
- lack of fuelwood, building materials, and other tree related products

Major land use problems (land users’ perception): Soil fertility decline

Type of cropping system and major crops comments: After land preparation, maize is planted followed by the legumes (mainly beans), depending on the rainfall regime

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

• agroforestry
• improved ground/ vegetation cover
• improved plant varieties/ animal breeds

3.6 SLM measures comprising the Technology

Comments:

Main measures: vegetative measures

Secondary measures: structural measures

Type of vegetative measures: scattered / dispersed

3.7 Main types of land degradation addressed by the Technology

Comments:

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

Main causes of degradation: deforestation / removal of natural vegetation (incl. forest fires) (Common access to resources (communal land ownership))

Secondary causes of degradation: over-exploitation of vegetation for domestic use (Increased population pressure on land), other human induced causes (specify) (Agricultural causes - Opening up of more agricultural land), land tenure (Before land registration, land users were reluctant to undertake long term investment)

3.8 Prevention, reduction, or restoration of land degradation

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

• reduce land degradation

Comments:

Main goals: mitigation / reduction of land degradation

4.1 Technical drawing of the Technology

4.2 General information regarding the calculation of inputs and costs

Specify currency used for cost calculations:

• USD

other/ national currency (specify):

Kenya shilling

4.3 Establishment activities

	Activity	Timing (season)
1.	Dig planting pits	before rainy seasons
2.	Purchase seedlings from nurseries/collection of wildings	Onset of the rains
3.	Transplant	Onset of the rains

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	Digging holes	ha	1.0	25.0	25.0	100.0
Equipment	Tools	ha	1.0	10.0	10.0	100.0
Plant material	Seedlings	ha	1.0	125.0	125.0	100.0
Total costs for establishment of the Technology					160.0
Total costs for establishment of the Technology in USD					160.0

Comments:

Duration of establishment phase: 24 month(s)

4.5 Maintenance/ recurrent activities

	Activity	Timing/ frequency
1.	Weeding around seedlings when necessary	rainy season /when necessary
2.	Pruning as necessary (pruned branches are dried and used for	Dry season /annual
3.	Pollarding (pruning of side branches; ensures large and straight	Dry season /annual, after crop harvest
4.	Root pruning: dig a trench (60 cm from tree, 25 cm deep) and cut
5.	Felling some trees to reduce density as they grow bigger	Dry season /when necessary
6.	Replanting if/when trees are harvested for timber.	Onset of rain /when necessary

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, prunning etc.	ha	1.0	65.0	65.0	100.0
Equipment	Tools	ha	1.0	25.0	25.0	100.0
Total costs for maintenance of the Technology					90.0
Total costs for maintenance of the Technology in USD					90.0

Comments:

Basis of costing: boundary planting (assuming average plot size of 25 m x 25 m (0.16 ha) and an average spacing of 1 m between trees = 1,000 trees/ha. 1 person plants 50 trees in one day. The labour required for management (pruning and pollarding) of established trees is high. Seedling purchase price is also high, but this can be reduced by collecting ‘wildings’ (seedlings growing in the wild) as well as establishment of personal or group nurseries.

4.7 Most important factors affecting the costs

Describe the most determinate factors affecting the costs:

high labour demand for nagement (pruning and pollarding) of established trees. Seedling purchase price is also high and increases as demand rises.

5.1 Climate

5.2 Topography

Comments and further specifications on topography:

Landforms: Also footslopes and valley floors

Slopes on average: Also moderate and steep

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 depth on average: Also moderately deep

Soil fertility is very low - medium and soils are exhausted due to continous cropping and few inputs. Soil erosion is also a big threat.

Topsoil organic matter is low - medium because crop residues rarely left to allow fertility to build-up. Some manure added but generally insufficient.

Soil drainage / infiltration is good because of the slopy and deep well drained nitosols

Soil water storage capacity is low - high

5.6 Characteristics of land users applying the Technology

Indicate other relevant characteristics of the land users:

Population density: > 500 persons/km2

Annual population growth: 2% - 3%

5% of the land users are rich and own 3% of the land.
60% of the land users are average wealthy and own 80% of the land.
30% of the land users are poor and own 15% of the land.
5% of the land users are poor and own 2% of the land.

Off-farm income specification: Few land users have off farm employment.

Market orientation of production system: Coffee, macadamia nuts, grevillea timber, and milk

5.7 Average area of land used 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

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

Biodiversity: vegetation, animals

Climate and disaster risk reduction

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	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	well
local windstorm	not known

Climatological disasters

	How does the Technology cope with it?
drought	well

Hydrological disasters

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

Comments:

High tolerance to temperature changes and rainfall, Grevillea grows in a wide variety of climates

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

• 11-50%

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

120 household in an area of 1.5 sq km (>500 persons/sq km)

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

• 91-100%

Comments:

100% of land user families have adopted the Technology without any external material support

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

Comments on spontaneous adoption: survey results

There is no trend towards spontaneous adoption of the Technology

Comments on adoption trend: 100% of land users have adopted the technology, but harvested trees are immediately replaced.

6.7 Strengths/ advantages/ opportunities of the Technology

Strengths/ advantages/ opportunities in the land user’s view
Reduction of runoff and raindrop strength

Strengths/ advantages/ opportunities in the compiler’s or other key resource person’s view
Multipurpose tree, meeting various socio-economic needs: provision of fuelwood (for household energy needs) and timber, boundary marking, ornamental function; leaves provide fodder during severe drought How can they be sustained / enhanced? Selfsustaining (no action needed).
Ease of propagation with minimal technical skill How can they be sustained / enhanced? Self-sustaining (no action needed).
Income generation opportunities (eg selling tree products) How can they be sustained / enhanced? Improvement in rural access roads to facilitate transport of tree products and other farm produce to market; encourage diversification: eg furniture making.
Microclimate improvement.
Crop yields are boosted by the tree nutrient recycling, fallen leaves add organic matter on decomposition. Reduction of runoff and hence soil erosion can be significant. The tree canopy associated with an understorey of litter reduces raindrop impact while the roots hold soil in place.

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?
On the slopes, the effectiveness of agroforestry is limited, in the fight against soil erosion	Combine with agronomic and vegetative measures (contour plowing, mulching, grass strips) and if necessary with structural measures (terraces, bunds and ditches)

Weaknesses/ disadvantages/ risks in the compiler’s or other key resource person’s view	How can they be overcome?
Seedlings and wildings not always readily available	Encourage local seed collection and setting up of group tree nurseries.
Timber susceptibility to pests attack	Timber treatment with appropriate chemicals; breeding of more pest tolerant varieties – particularly against weevils.
Livestock sometimes damage the young seedlings	Protection by fencing.
Dry periods result in low seedling survival rates: planting not possible in dry areas	With water harvesting and moisture management techniques, the technology could spread to lower rainfall areas.
Cultural conflicts	Trim the branches of the trunk regularly; Dig a small trench around the trees to cut the superficial roots

7.2 References to available publications

Title, author, year, ISBN:

ICRAF. 1992. A selection of useful trees and shrubs in Kenya. ICRAF, Nairobi

Title, author, year, ISBN:

Guto et al. 1998. PRA report, Kiawanja catchment, Nembure division, Embu District-Kenya. Ministry of Agriculture, Nembure division, Embu

Title, author, year, ISBN:

Harwood CE. 1989. Grevillea robusta: an annotated bibliography: ICRAF, Nairobi

7.3 Links to relevant online information

Title/ description:

Rocheleau D., F. Weber and A .Field-Juma. 1988. Agroforestry in dryland Africa: ICRAF, Nairobi

URL:

http://www.ces.uga.edu/pubcd/b949-w.html , http://www.winrock.org/forestry/factpub/factsh/grevillea.html