Cashew living fence on a ditch next to an irrigation channel (Stefan Graf)

Cashew living fences (Cambodia)ដំណំ◌ាចនីដំ◌ា របងរស់ (Khmer)

DESCRIPTION

Living fences of cashew, reinforced with bamboo and/or barbed wire, are used to keepLiving fences of cashew, reinforced with bamboo and/or barbed wire, are used to keepthe cattle off the garden or the rice seedbed.the cattle off the garden or the rice seedbed.Cashews (Anacardium occidentale) are fast growing, waterlogging tolerant tropical treesthat can be used as living fences. The cashews act as fence posts, and are reinforced withbamboo poles and/or barbed wire. The living fences are used to either fence cattle intofields or fence them off, usually around the house. The fenced areas can be plantedduring the dry season. Without fences, the cattle are free roaming and use to destroy thecrops.Besides fencing the cattle, the purposes of cashew living fences are the production ofnuts and fruits, fuel, and soil enhancer. The nuts are sold, but there is no market for thefruits, thus they are fed to cattle or let to rot. The wood is used to cook or to producecharcoal; the ash is added to the compost. The leaves are gathered as well and added tothe compost.Although cashews can stand waterlogged conditions, they prefer a well-drained soil.Thus a small berm is built up on the emplacement of the fence, and sown with cashewseeds spaced from 0.5 to 3 m. Cashews grow faster when directly sown than whentransplanted. The spacing varies according to the farmers’ purpose. If a higherproduction of nuts is intended, the spacing is wider; if the fence is more important, theplants are grown closer. Cattle do not eat the leaves and branches, thus do not needprotection from grazing. One year after sowing the cashews, the trees are tall enough toact as fence posts and support bamboo pole as well as barbed wire. The bamboo iseither gathered from the wild or grown in the fields and home gardens. The bamboo isfixed to the living posts with natural fibers/vines or old clothes, and has to be replacedevery two to three years to withstand cattle.The analysed area is flat (slope < 2%), with a tropical climate (dry season from Novemberto May and wet season from June to October), and the soils are mostly sandy or loamy.The soil has a low fertility, contains little organic matter, and acidifies. The area has beendeforested a long time ago, and the groundwater table is rather high (1-2 m during thedry season, on the surface during wet season). Due to climate change, farmers notice more erratic rainfalls, temperature rises andmore recurrent droughts. Rice is the predominant crop grown in the area, since it servesas staple food (mix subsistence and commercial activities). Cattle are usually grazing onthe fields after the harvest, without much control. Thus the cattle grazes too often andtoo much on the same spot, leading to degradation.The increasing migration rate (the young generation leaves the villages to work in thecities, garment industry or abroad) results in a decrease of available labour force in thearea which has detrimental effects on the agricultural activities. Furthermore, the civilwar in the 1970s (Khmer Rouge) led to the loss of agricultural knowledge. Several NGOsare trying to re-establish the knowledge.

LOCATION

Location:Location: Krang Liav, Rolea Pha-er,Kampong Chhnang, Cambodia

No. of Technology sites analysed:No. of Technology sites analysed:

Geo-reference of selected sitesGeo-reference of selected sites104.55439, 12.22968

Spread of the Technology:Spread of the Technology: evenly spreadover an area (approx. < 0.1 km2 (10 ha))

Date of implementation:Date of implementation: 10-50 years ago

Type of introductionType of introductionthrough land users' innovation✓as part of a traditional system (> 50years)during experiments/ researchthrough projects/ externalinterventions

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Cashew living fence on a ditch next to an irrigation channel(Stefan Graf)

Close view on a cashew living fence, with bamboo poles andbarbed wire. (Stefan Graf)

CLASSIFICATION OF THE TECHNOLOGY

Main purposeMain purposeimprove productionreduce, prevent, restore land degradationconserve ecosystem✓protect a watershed/ downstream areas – in combination withother Technologiespreserve/ improve biodiversityreduce risk of disastersadapt to climate change/ extremes and its impactsmitigate climate change and its impactscreate beneficial economic impactcreate beneficial social impact

Land useLand useMixed (crops/ grazing/ trees), incl. agroforestryMixed (crops/ grazing/ trees), incl. agroforestry - Silvo-pastoralism

Water supplyWater supply

Number of growing seasons per year:Number of growing seasons per year: 1Land use before implementation of the Technology:Land use before implementation of the Technology: n.a.Livestock density:Livestock density: 25-50 LU /km2

rainfedmixed rainfed-irrigated✓full irrigation

Purpose related to land degradationPurpose related to land degradationprevent land degradationreduce land degradation✓restore/ rehabilitate severely degraded land✓adapt to land degradationnot applicable

Degradation addressedDegradation addressedsoil erosion by windsoil erosion by wind - Et: loss of topsoil

chemical soil deteriorationchemical soil deterioration - Cn: fertility decline andreduced organic matter content (not caused by erosion)

biological degradationbiological degradation - Bc: reduction of vegetationcover, Bl: loss of soil life

SLM groupSLM groupintegrated crop-livestock management

SLM measuresSLM measuresvegetative measuresvegetative measures - V1: Tree and shrub cover

TECHNICAL DRAWING

Technical specificationsTechnical specifications

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Author: Stefan Graf, Switzerland

On a dike cashews (Anacardium occidentale) wereplanted a few years back. After they grew up, thefence was done with barbed wire and bamboopoles.Kampong ChhnangDate: 2014

Technical knowledge required for field staff /advisors: lowTechnical knowledge required for land users: lowMain technical functions: increase of biomass(quantity), spatial arrangement and diversificationof land useSecondary technical functions: increase in organicmatter, increase in nutrient availability (supply,recycling,…), improvement of water quality,buffering / filtering water, reduction in wind speed

Aligned: -along boundaryVegetative material: T : trees / shrubs, F : fruit trees/ shrubsVertical interval within rows / strips / blocks (m):0.5-3mFruit trees / shrubs species: Cashew, seeded.

ESTABLISHMENT AND MAINTENANCE: ACTIVITIES, INPUTS AND COSTS

Calculation of inputs and costsCalculation of inputs and costsCosts are calculated:Currency used for cost calculation: n.a.n.a.Exchange rate (to USD): 1 USD = n.aAverage wage cost of hired labour per day: 5.00

Most important factors affecting the costsMost important factors affecting the costsThe costs are most determined by the availability of bamboo. Ifit is not grown in the garden, it has to be gathered in the forestthat is related to time consuming transportation. Or barbedwire has to be purchased. Note: The time used to gather theleaves for the compost or to cut the branches to makecharcoal/ash as soil amendment was not included in therecurrent activities as these activities are neither related to themain purpose of living fences nor done by all the farmersapplying this technology.

Establishment activitiesEstablishment activities1. Building small bound to sow the cashews. (Timing/ frequency: Dry season, before sowing)2. Sowing cashews on the bounds (Timing/ frequency: Beginning of rainy season)3. Gathering bamboo in the forest, building the fence (Timing/ frequency: None)

Establishment inputs and costsEstablishment inputs and costs

Specify inputSpecify input UnitUnit QuantityQuantityCosts perCosts perUnit (n.a.)Unit (n.a.)

Total costsTotal costsper inputper input

(n.a.)(n.a.)

% of costs% of costsborne byborne by

land usersland usersLabourLabourlabour 1.0 17.5 17.5 100.0EquipmentEquipmenttools 1.0 12.0 12.0 100.0barbed wire 1.0 21.0 21.0 100.0Plant materialPlant materialseeds 1.0 1.0 1.0 100.0Total costs for establishment of the TechnologyTotal costs for establishment of the Technology 51.551.5

Maintenance activitiesMaintenance activities1. Gathering bamboo in the forest, building the fence (Timing/ frequency: Every 2-3 years)

Maintenance inputs and costsMaintenance inputs and costs

Specify inputSpecify input UnitUnit QuantityQuantityCosts perCosts perUnit (n.a.)Unit (n.a.)

Total costsTotal costsper inputper input

(n.a.)(n.a.)

% of costs% of costsborne byborne by

land usersland usersLabourLabourlabour 1.0 3.0 3.0 100.0Total costs for maintenance of the TechnologyTotal costs for maintenance of the Technology 3.03.0

NATURAL ENVIRONMENT

Average annual rainfallAverage annual rainfall< 250 mm251-500 mm501-750 mm751-1,000 mm1,001-1,500 mm✓1,501-2,000 mm

Agro-climatic zoneAgro-climatic zonehumidsub-humid✓semi-aridarid

Specifications on climateSpecifications on climate1486.45 mm 2013 in Kampong Chhnang Thermal climate class: tropics. 27-35°C

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2,001-3,000 mm3,001-4,000 mm> 4,000 mm

SlopeSlopeflat (0-2%)✓gentle (3-5%)moderate (6-10%)rolling (11-15%)hilly (16-30%)steep (31-60%)very steep (>60%)

LandformsLandformsplateau/plains✓ridgesmountain slopeshill slopesfootslopesvalley floors

AltitudeAltitude0-100 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.

Technology is applied inTechnology is applied inconvex situationsconcave situationsnot relevant

Soil depthSoil depthvery shallow (0-20 cm)shallow (21-50 cm)✓moderately deep (51-80 cm)deep (81-120 cm)very deep (> 120 cm)

Soil texture (topsoil)Soil texture (topsoil)coarse/ light (sandy)✓medium (loamy, silty)✓fine/ heavy (clay)

Soil texture (> 20 cm belowSoil texture (> 20 cm belowsurface)surface)

coarse/ light (sandy)medium (loamy, silty)fine/ heavy (clay)

Topsoil organic matter contentTopsoil organic matter contenthigh (>3%)medium (1-3%)✓low (<1%)✓

Groundwater tableGroundwater tableon surface✓< 5 m5-50 m> 50 m

Availability of surface waterAvailability of surface waterexcessgood✓mediumpoor/ none

Water quality (untreated)Water quality (untreated)good drinking waterpoor drinking water(treatment required)

✓for agricultural use only(irrigation)unusable

Is salinity a problem?Is salinity a problem?

Occurrence of floodingOccurrence of flooding

YesNo

YesNo

Species diversitySpecies diversityhighmedium✓low

Habitat diversityHabitat diversityhighmedium✓low

CHARACTERISTICS OF LAND USERS APPLYING THE TECHNOLOGY

Market orientationMarket orientationsubsistence (self-supply)mixed (subsistence/commercial

✓commercial/ market

Off-farm incomeOff-farm incomeless than 10% of all income10-50% of all income✓> 50% of all income

Relative level of wealthRelative level of wealthvery poorpooraverage✓richvery rich

Level of mechanizationLevel of mechanizationmanual work✓animal traction✓mechanized/ motorized

Sedentary or nomadicSedentary or nomadicSedentarySemi-nomadicNomadic

Individuals or groupsIndividuals or groupsindividual/ household✓groups/ communitycooperativeemployee (company,government)

GenderGenderwomen✓men✓

AgeAgechildrenyouthmiddle-agedelderly

Area used per householdArea used per household< 0.5 ha0.5-1 ha1-2 ha✓2-5 ha5-15 ha15-50 ha50-100 ha100-500 ha500-1,000 ha1,000-10,000 ha> 10,000 ha

ScaleScalesmall-scalemedium-scale✓large-scale

Land ownershipLand ownershipstatecompanycommunal/ village✓groupindividual, not titled✓individual, titled

Land use rightsLand use rights

Water use rightsWater use rights

open access (unorganized)communal (organized)✓leasedindividual✓open access (unorganized)✓communal (organized)leasedindividual

Access to services and infrastructureAccess to services and infrastructurehealth poor ✓ good

education poor ✓ good

technical assistance poor ✓ good

employment (e.g. off-farm) poor ✓ good

markets poor ✓ good

energy poor ✓ good

roads and transport poor ✓ good

drinking water and sanitation poor ✓ good

financial services poor ✓ good

IMPACTS

Socio-economic impactsSocio-economic impactsCrop production decreased ✓ increased

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Due to shading and root competition.wood production decreased ✓ increased

Used as fuel and charcoal.energy generation (e.g. hydro,bio)

decreased ✓ increased

Firewood production.demand for irrigation water increased ✓ decreased

Quality, trough bioremediation of groundwater.Difficult to quantify.

diversity of income sources decreased ✓ increased

If spaced, production of cashew nuts and apples.

Socio-cultural impactsSocio-cultural impactsfood security/ self-sufficiency reduced ✓ improved

Improved self-sufficiency on firewood.contribution to human well-being

decreased ✓ increased

Every additional income source/diversificationincreases the human well-being.

Ecological impactsEcological impactsevaporation increased ✓ decreased

But increased evapotranspiration.nutrient cycling/ recharge decreased ✓ increased

Nutrients are picked up from the groundwater, andput back into the cycle.

soil organic matter/ belowground C

decreased ✓ increased

Leaves used for compost.biomass/ above ground C decreased ✓ increased

beneficial species (predators,earthworms, pollinators)

decreased ✓ increased

Wormcasts could be seen under the trees. Difficult toquantify.

habitat diversity decreased ✓ increased

Tree layer.wind velocity increased ✓ decreased

Off-site impactsOff-site impactsgroundwater/ river pollution increased ✓ reduced

Bioremediation difficult to quantify.wind transported sediments increased ✓ reduced

Slowing down of wind speed.

COST-BENEFIT ANALYSIS

Benefits compared with establishment costsBenefits compared with establishment costsShort-term returns very negative ✓ very positive

Long-term returns very negative ✓ very positive

Benefits compared with maintenance costsBenefits compared with maintenance costsShort-term returns very negative ✓ very positive

Long-term returns very negative ✓ very positive

CLIMATE CHANGE

Gradual climate changeGradual climate change

Climate-related extremes (disasters)Climate-related extremes (disasters)

Other climate-related consequencesOther climate-related consequences

annual temperature increase not well at all ✓ very well

local rainstorm not well at all ✓ very well

local windstorm not well at all ✓ very well

drought not well at all ✓ very well

general (river) flood not well at all ✓ very well

reduced growing period not well at all ✓ very well

ADOPTION AND ADAPTATION

Percentage of land users in the area who have adopted thePercentage of land users in the area who have adopted theTechnologyTechnology

single cases/ experimental1-10%10-50%more than 50%

Of all those who have adopted the Technology, how many haveOf all those who have adopted the Technology, how many havedone so without receiving material incentives?done so without receiving material incentives?

0-10%10-50%50-90%90-100%

Has the Technology been modified recently to adapt to changingHas the Technology been modified recently to adapt to changingconditions?conditions?

To which changing conditions?To which changing conditions?

YesNo

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climatic change/ extremeschanging marketslabour availability (e.g. due to migration)

CONCLUSIONS AND LESSONS LEARNT

Strengths: land user's viewStrengths: land user's viewCattle are fenced in or off. The cattle do not enter the homegardens of the neighbours and cannot escape on the ricefields.Branches can be used as firewood or to make charcoal, andthe leaves can be used as compostProduction of fruits and nuts.

Strengths: compiler’s or other key resource person’s viewStrengths: compiler’s or other key resource person’s viewReduced wind speed.Bioremediation of groundwater.Increased soil cover.

Weaknesses/ disadvantages/ risks: land user's viewWeaknesses/ disadvantages/ risks: land user's view how toovercome

Shading of crops nearby. Cut back the cashews since theyare pollarding trees. However, this will drastically reduce thefruit production.Root competition with other trees. Plant next to shallowrooted crops.No more market for cashew apples as there is anoverproduction. Process as wine or dry. Can also be fed tocattle.

Weaknesses/ disadvantages/ risks: compiler’s or other keyWeaknesses/ disadvantages/ risks: compiler’s or other keyresource person’s viewresource person’s view how to overcome

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→REFERENCES

CompilerCompilerStefan Graf (graf.ste@gmx.ch)

ReviewerReviewerDeborah Niggli (deborah.niggli@cde.unibe.ch)

Date of documentationDate of documentation: Oct. 27, 2014 Last updateLast update: Feb. 28, 2017

Resource personsResource personsStefan Graf (graf.ste@gmx.ch) - SLM specialistLean Hak Khun (kleanghak@yahoo.com) - SLM specialistBin Sreytouch (Sreytouchbin@gmail.com ) - SLM specialistKhonhel Pith (khonhel@gmail.com) - SLM specialist

Full description in the WOCAT databaseFull description in the WOCAT databasehttps://qcat.wocat.net/en/wocat/technologies/view/technologies_1643/

Linked SLM dataLinked SLM datan.a.

Documentation was faciliated byDocumentation was faciliated byInstitution

Local Agricultural Research and Extension Centre (LAREC) - CambodiaSociety for Community Development in Cambodia (SOFDEC) - Cambodia

Projectn.a.

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