TechnicalReport

RestorationofDegradedLandsinWestAfricaSahel:ReviewofexperiencesinBurkinaFasoandNiger

WrittenbyBoubieVincentBado(ICRISAT)

PatriceSavadogo(ICRAF)MamanLaminouSanoussiManzo(ICRISAT)

Submittedto

WorldAgroforestryCentre(ICRAF)

FortheProjectTitled,RestorationofdegradedlandforfoodsecurityandpovertyreductioninEastAfricaand

theSahel:takingsuccessesinlandrestorationtoscale

Fundedby,InternationalFundforAgriculturalDevelopment(IFAD)

Thisworkisbeingundertakenaspartofthe

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TableofContents

1. Introduction..........................................................................................................................................32. LanddegradationinWestAfricaSahel........................................................................................43.HistoryofrestorationofdegradedlandsinWestAfricaSahel...............................................43.2BurkinaFaso....................................................................................................................................5

3.1Niger....................................................................................................................................................5

4.Experiencesofrestorationofdegradedlands..............................................................................64.1Valleranisystem.............................................................................................................................6

4.2Plantingtrenches...........................................................................................................................6

4.3Contourridges/tiedridges........................................................................................................7

4.4Contourbunds................................................................................................................................7

4.5Contourstonebunds....................................................................................................................8

4.6Contourlinecultivation..............................................................................................................8

4.7Vegetativestrips............................................................................................................................9

4.8Mulching............................................................................................................................................9

4.9Sanddunestabilization...............................................................................................................9

4.10FarmerManagedNaturalRegeneration........................................................................10

4.11Stonebunds-farmernaturalregeneration.................................................................10

4.12Zaïtechnique.............................................................................................................................11

4.13Zaï-Stonebunds........................................................................................................................12

4.14Zaï-Stonebunds-FarmerManagedNaturalRegeneration.....................................12

4.15Semicircularbunds.................................................................................................................12

4.16Agroforestry-Semicircularbunds.....................................................................................12

4.17Bio-reclamationofdegradedlands..................................................................................13

4.18Agroforestryparklandsystems.........................................................................................13

5.Conclusion...............................................................................................................................................136. References...........................................................................................................................................15

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1. IntroductionWaterconstraintsandtheinherentsoilpovertyarethemajorfactorsthatlimitcropyieldsandproductivity of cropping systems inWest Africa Sahel (WAS). Livestock is notwell integratedwithagriculturalactivitiesandcropresiduesareusuallyexportedfromthefarmforhouseholdneeds and animal feeding. In traditional systems, soil fertility maintenance was based on arelatively longfallowperiod(10-15years) followedbyashortcroppingperiodof3to5years.Buttheincreasedpopulationpressurehasresultedinsignificantchangesofthetraditionalbush-fallowsystem.Landsarenowcontinuouslycultivatedfor longperiodwith lowexternal inputs,leadingtosoilfertilitydeclineovertime(BationoandMokwunye1991;Bekundaetal.2010).Inadditiontobiophysicalaspects,awiderangeofsocio-economicfactorssuchasthelowfinancialcapacitiesofpoorfarmerstoinvestinagriculturalinputs,highpressureonecologicalresourcesfor food, fodder or energy, also add to the stress on the systems. Failure by the smallholderfarmers to intensifyagriculturalproduction inamanner thatmaintains soilproductivity is themaincauseoflanddegradation,particularlyinthefragileecosystemsofWAS.

Land degradation is defined as a process that leads to the reduction of land productivity foruseful purposes, and is typically a result of soil, wind, or water erosion; soil salinization;waterlogging; chemical deterioration; or any combination of these factors (Adeel 2003). Landdegradationisaglobalproblem,particularlyinthedryareas,hometoalargepopulationofpoorfarmers, where land degradation and water scarcity are major threats to food security. Theimpactsoflanddegradationaresevereonbothhumansocietyandecosystems.Desertificationisoftenwronglyattributedsolelytodroughts,butitisthedeadlycombinationofcontinuedlandabuse during periods of deficient rainfall that results in unproductive land, and ultimatelydesertification (UNESCO2003).Combatingdesertificationby rehabilitatingdegraded landscanbedonesuccessfully,usingexisting,oftentraditionaltechniques.

Land restoration involves restoring the fertilityofdegraded lands.Thesocial syndromewherediminishingavailabilityof lands, inherent low fertility, continuoussoilerosion,andcontinuousnutrient removalwithout replenishment, results in a spiraling downfall in productive capacityand a diminished resilience of the soil system to provide a suitablemedium for crop growthneeds tobeaddressed.Smallholder farmersareat thecenterofbothsoil fertilitydeclineandrestorationprocess.Theirdecisionstomanage,toutilizetechnologiesandtoimproveorrestoresoilfertilityareguidedbythesocioeconomicconditionsandtheoverallbenefitsthatwillaccruefromproduction(SangingaandWoomer,2009;Bekundaetal.2010).Asustainablemanagementoflandsundercultivationandtherestorationofdegraded landscouldbeachievedbyaffordablestrategic management innovations; taking into account the socioeconomic conditions offarmers.Whileindividualtechnologiescancontribute;amoreintegratedsystemsthatcombinestechnologies, crops, and trees such as the agroforestry systems could better contribute forsustainablemanagementofnaturalresources.

Manyeffortshavebeeninvestedtodevelopingstrategiesandapproachesforbothsustainablemanagement of natural resources and restoration of degraded lands inWAS. In some cases,farmercommunitieshavedevelopedsound, sustainableapproaches to landrehabilitationandmanagement but there is insufficient information on successful restoration in the context ofWAS,particularwith regards topolicy, institutionsandsocioeconomicconditionsunderwhichspecific approaches could be adapted and applied successfully (Bunning 2003). The mainobjective of this review was to investigate the main experiences of regenerating degradedlandscapes (RDL) in Niger. Going through the documentation, we found many similarities inexperiencesacrossthetwocountriesofNigerandBurkina.SomeinterestingexperienceswerefoundinBurkina,Nigeroratthesametimeinthetwocountries.Wefinallydecidedtoextend

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thereviewtothetwocountriesasarepresentativezoneoftheWAS.Thecriticalissueintakingrestoration to scale is thatecological, economicand institutional context variesat fine scales.ThemaingoalofthisreviewistoidentifythespecificitiesandthecontextofthemostefficientexperiencesofRDLthatcouldbewidelyscaledintheWAS.

2. LanddegradationinWestAfricaSahelLarge areas of WAS are prone to land degradation. There is a permanent competition formoistureandnutrients forcrops, fodder,energy,etc., leadingtotheremovalofcropresiduesandprotectivegrasscover,andwithfrequentdroughts,thisleavesthesoilhighlyvulnerabletowind erosion. Heavy grazing prevents or delays regrowth of the vegetation, wind erosionremovestopsoil,whileblownsandmaydamagecropsorcovercroplands.Heavyrainsfollowinga longdryperiod,maysealthesoilsurface,causerunoffs,anderodebaresoil.ManyareasofWAShavebecomemorevulnerabletodegradation,particularlyfrom1930sto1960s(Bunning2003).

Degradationandrestoration isacontinuousprocess.Corecomponentsof landrestorationarerecoveryofvegetationandtheimprovementandmaintenanceofthesoilhealth.Reductionoflandproductivityandthehighpopulationgrowth leadstohighpressureonthecultivatedandmarginallands.Theimmediatecausesaredeforestation,poormanagementofwaterresources,decreaseinsoilfertility;increaseofcultivatedlands;theviciouscycle(Adeel,2003).

Themainagro-silvo-pastoralzoneofBurkinaandNigerarelocalizedinthedrysemi-aridzoneofWAS (Figure 1). In Burkina Faso, 34% (92,345 million ha) of cropland are degraded. It isestimated that 100,000 to 250,000 ha of land are annually degraded and 74% of land aredegradedorpronetodegradation (Hien2015. InNiger,40-50%of the landswereaffectedbydeforestationinlessthan30years(between1958and1997).Around80,000to120,000haareannuallydegraded.ThecountriesofWAShaveputmanyeffortstocombatdesertificationandrestoration of the degraded lands. An intergovernmental institution named ‘’Inter StateCommitteeagainstDesertificationintheSahel’’(CILSSinFrench)wascreatedafterthedroughtintheyears1970s.ManyprogramsandprojectshavebeenimplementedbyCILSSinitsmembercountries. Somewere regional, covering twoormore countries but othersweredesigned fornationalorlocalspecificactions.Manysuccessfulexperienceswereobtained,alongwithsomefailures. The CILSS has made an effort to document its 40 years experiences to combatingdesertification(Hienetla.,2015.ApartfromthisdocumentationofCILSS,therehavebeenafewsyntheses on the broad effectiveness to address land degradation and the restorationexperiencesalthoughtherehavebeenmanyaccountsofindividualsuccessfuleffortsthathavebeensummarizedasgoodpractice,includingasetoflessonslearnedfromtherehabilitationofdegraded lands (UNESCO,2003;Blayetal. 2004). Fewof theseeffortshavegone so faras tocriticallyassesstheelementsthatallowedthemtomakelarge-scaleimpacts.Beforemakingthereview of technologies and experiences, the history of the actions against land degradationcould help to better capture the evolution of the concepts, strategies and the innovativeadaptations.3.HistoryofrestorationofdegradedlandsinWestAfricaSahelThe countries of the WAS were already working on RDL before the creation of CILSS, theintergovernmentalinstitution.Dependingofthecountry,differentinitiativesandprojectswereimplementedatlocalornationallevels.

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Figure1.EcologicalzonesofBurkinaandNigerinWestAfricaSahel.

3.2BurkinaFasoTheinitiativesofRDLinBurkinastartedin1960withtheproject"GERESVolta"(Hien2015).Thisproject aimed to create a “psychological shock" to raise awareness of the degradation ofagriculturallandsusingtraditionaltechniques.Theprojectsetup120,000haofdegradedlandstreated with anti-erosion techniques using the earthen benches. With the participation ofcommunities, treesand stripsAndropogoneaewereplantedalong thebenches.Otheractionswere undertaken in the 1970s. The program '’Development of Authority Volta Valleys’’ (AVV)whichbecame ‘’NationalOffice for LandManagement’’ (ONAT), introduced the techniquesof"stripes". In 1976 the Water and Rural Equipment Fund (FEER) launched a program onRestorationof soils (DRS). From1980sand takingadvantageof theexperienceof FEER,moreintegratedapproachesweredevelopedwiththe"integrateddevelopmentprojects".Theearthbenches were replacing by stone bunds. Many NGOs and projects have investedmajorly inthese integrated management techniques. Most innovations in RDL originate from theseexperiences.

3.1NigerAsinBurkina,thefirstactionsofRDLinNigerstartedin1960(Hienetal.,2015).Thetechniquesof half-moons, stone bunds and benches were introduced later. The strategies of "food forwork"and/or"cash forwork"wereusedtomobilizecommunities,but theactionswereoftenpunctualwithlimitedimpacts.SignificantresultswereobtainedintheRDLsincethedroughtof1970s,withstrongpoliticalengagement.AnewstrategyinvolvingthecommunitieswasadoptedasanessentialelementofsustainablemanagementandRDL.Thenationalstrategystatesthat:'the fight against desertification for food security must contribute to improving productionsystemsaspartofthesearchforfoodself-sufficiency’’.Manyconcreteactionshavesupportedthispoliticalcommitment.Followingtheseverefoodcrisisof1984-1985,IFAD'ssupportthrough

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itsSpecialProgrammeforsub-SaharanAfricancountries,strengthenedtheactionsofRDLintheSahel, particularly in Niger. Building on indigenous practices and technologies, the programcontributedsignificantlytotheRDLinNiger.4.ExperiencesofrestorationofdegradedlandsThe techniques of RDL vary from simple individual technologies to more complex systemscombiningoneormoretechnologieswithmanagementpractices.TheindividualtechnologiesofRDLaregenerallydeveloped,adaptedorimprovedfromtraditionalpracticesbyresearchers.Inthe scaling process, farmers tend to adapt or combine the new technologies with their ownpractices.Atfarmer’slevel,thereisnoclearbarrierbetweentechnologiesforRDLorsustainablemanagementoflands(SML).Dependingofthebiophysicalandsocioeconomicconditions,theyadoptoradaptone,twoormoretechniquestomanagetheircroppingsystem.Manyofthemhavebeen identified. Somearewidelyusedat regional levelwhileothers aremore localized.TheCILSSmadeadescriptiveinventoryofthesetechniquesandtheirperformances(Hienetal.,2015). An inventory from individual technologies to more complex systems could helpunderstandthetechnicalprogressunderRDLinWAS.

4.1ValleranisystemThe Vallerani system is a relatively new system of water harvesting where a special tractor-pulled plough is used to automatically constructwater-harvesting catchments. This system isideally suited for large-scale reclamationwork. The Vallerani implement is amodified ploughnamed Delfino3, pulled by a heavy-duty tractor (Figure 2). The Delfino3 plough has a singlereversible ploughshare that creates an angled furrow and piles up the excavated soil on thelower(downhill)sideofthefurrow.Thissoilformsaridgethatstopsorslowsdownrunoffwateras it flows downhill. The Vallerani system is intended for use with direct sowing of seeds ofshrubsandtrees.Seedsaresownalongtheridgesofthebasinsandinthewakeoftheripper.Withmoremoistureavailableforalongerperiodoftime,treesgrowrapidlyandtheherbaceouscoverimprovesinqualityandinquantity;providing20-30timesmorelivestockfodder(1,000-2,000 kg dry herbaceous biomass/ha/year), and also helps conserve the soil (Schmidt et al.2010;MekdaschiStuderandLiniger2013;RayandSimpson2014).

Figure2.Velleranisystemtocreatewaterharvestingcatchments.Photo:W.CritchleyfromMekdaschiStuderandLiniger(2013)

4.2PlantingtrenchesThemain purpose of this technique is to restore tree cover and prevent soil erosion on theslopes by reducing water flow that threatens the land in the downstream. The established

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trenchesreducegullyerosionandsedimentationofareaswithafragilesoilstructure.Itpermitsthereintroductionoftreesondegraded,unfertilelandandcontributestodissipatingtheforceofrunoffandincreasesinfiltration.Areasrestoredusingplantingtrenchescansubsequentlybeexploitedtoalimitedextentinaccordancewithcarefulmanagementpractices.Theinfiltrationof water into planting trenches can contribute to groundwater recharge. This technique hasproved effective inrestoring forest/ rangeland on highly degradedsites. The progressivedevelopmentofgrassandtreecovercontinuesonthesesitesforyearsafteritsestablishment.However, the young trees must be monitored for several years to ensure that stray grazinganimalsdonotdamagethemanddriedupplants/treesmustbereplaced(GIZ,2012;RayandSimpson2014).

4.3Contourridges/tiedridgesContourridgesorcontourplowing,arecommonlyusedworldwideincropproduction.Thisisamicrocatchment technique.Ridges followthecontourataspacingofusually1 to2m.Runoffcollects and is stored in the furrow between ridges. Crops are typically planted on the ridgetops.Additionally,tiescanbeaddedtothesystem,consistingoflowridgedorbarrier,betweentheprincipleridges,thuscreatingmicrocatchmentswithinthefurrows.Theuseoftiesishelpfulinpreventingwaterfromaccumulatinginlowspotsandpotentiallybreachingridgesonslopes.Thetiesareparticularlyusefulonundulatingterrain,orinsituationswhereprecisecontouringisnotpossible.Thesystem,withorwithoutties,issimpletoconstructandamenabletousewithanimaltractionortractors.Specialattachments(foranimaltractionandtractors)areavailabletofacilitatecreationof“ties.”Theyieldofrunofffromveryshortcatchmentlengthsisextremelyefficientandwhendesignedandconstructedcorrectlythereshouldbenolossofrunoffoutofthe system. Another advantage is an even crop growth due to the fact that each plant hasapproximatelythesamecontributingcatchmentarea(DeusonandSanders1990;Critchleyetal.1991;RayandSimpson2014).

4.4ContourbundsContour bunds are used in crop agriculture and the establishment of trees. As the nameindicates, thebundsareestablishedfollowingthecontour,atclosespacing.Withtheoptionalinclusionofsmallearth“ties,” formedlaterallybetweenthebunds,thesystemcanbedividedinto individualmicro catchments (Figure 3). The construction of contour bunds lends itself tomechanization (animal-traction and/or tractors). The technique is therefore suitable forimplementationona largerscale.Themajoradvantageofcontourbunds is their suitability tocropcultivationbetween thebunds.Aswithother formsofmicrocatchmentwaterharvestingtechniques, theyieldof runoff ishigh,andwhendesignedcorrectly, there isno lossof runoffoutofthesystem(Critchleyetal.1991Naganoetal.2002;RayandSimpson2014).

Figure3.ContourBundsfortrees,Caffreyetal.(2014).Credit:Critchleyetal.1991

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4.5Contourstonebunds

Theuseofbunds,orlinesofstones,isatraditionalpracticeofSahelianWestAfrica,notablyinBurkina Faso (RayandSimpson2014).Contour stonebundsareused to slowdownand filterrunoff, thereby increasing infiltration and capturing sediment. The water and sedimentharvested leaddirectly to improvedcropperformance (Figure4).This technique iswell suitedfor small-scale applicationon farmer’s fields and, givenanadequate supplyof stones, canbeimplementedquickly and cheaply over large areas. The great advantageof systemsbasedonstoneisthatthereisnoneedforspillways,wherepotentiallydamagingflowsareconcentrated.The filteringeffectof the semi-permeablebarrierprovidesabetter spreadingeffectof runoffthanearthbunds,whichattempttocapturerunoff.Furthermore,stonebundsrequiremuchlessmaintenance,althoughperiodicmaintenanceisrequired,especiallytorepairdamagecausedbycattlemovement.Theuseofstonebundsforwaterharvestinghasevolvedintovariousforms,making it an effective technique which is both popular and quickly mastered by farmers(Critchley et al. 1991; Soméet al. 2000;Nyssen et al. 2007; Ray and Simpson2014). But onemainconstraintofthistechniqueistheunavailabilityofstonesinsomeplacessuchasinregionswithsandysoil.

Figure4.Implementationofthecontourstonebands.Photo:HienF

4.6ContourlinecultivationAvariationintheuseofcontourbunds,theContourLineCultivation(CLC)orAménagementenCourbes de Niveau (ACN) in French, is a holistic landscape approach to manage water andcapturerainfallonawatershedscale.TheapproachwasdevelopedinMalibyresearchersoftheInstitut d’Economie Rurale (IER) and Centre de Coopération Internationale en RechercheAgronomiquepour leDéveloppement (CIRAD). Theprincipal objectives of the CLC technologyare:a)tocaptureandretrainrainfall intreatedfields,b)assistevacuationofexcessiverainfallanddestructive surface flow thatmay runonto fieldsduringheavy stormevents. The systemconsistsofestablishingpermanentridges(Ados)about100cmwidethatareconstructedonthecontour and maintained in subsequent years. Smaller ridges are then established throughnormalplowingthatfollowthecontourindicatedbythepermanentAdos.Otherstructuresmayberequired,suchasoverfloworevacuationchannelstoremoveexcessivewater.Treatedfieldscanincreaseinfiltrationofrainwaterbyupto10%ofthetotalannualrainfall,eveninfieldswithagentle slopeof1 to3%.The increased ratesofwater infiltrationwithACNsuggest that thereduction in surface runoff of rainwater results in greater capture and deeper percolation ofwaterintothesoil(Kablanetal.2008;RayandSimpson2014)

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4.7VegetativestripsVegetativestrips,eithernaturallyoccurringorplanted,aretraditionallyusedtodemarcateandprotect fieldsbyfarmers invariouspartsofAfrica.Therecommendeduseofcontourbarriers,vegetativebarriersandhedgerowsofmultipurposetrees,havebeenpromotedinvariousformssincethe1980s.Technically,vegetativestripsarenarrowbandsofnaturallyoccurringorplantedgrasses,otherplantsandtrees.Contourlinesarelaidoutandstakedtoserveasaninitialguideforplugging,withwidestripsleftunpluggedtoallowvegetationtoestablish.Alternatively,thestakedcontoursareusedtoguidetheplantingofspecies,suchasvetivergrass.Ineithercase,rainfallrunoffflowingdownslopeisslowed,andinfiltrateswhenitreachesthevegetativestrips.As the water movement slows, suspended soil particles collect above the strips and naturalterracesformovertime.Thislevelingisassistedbypluggingalongthecontourbetweenthestripwhichcausessome‘tillageerosion’thatalsomovessoildownslope.Vegetativestripsconstitutea low-cost technique with modest labor demands for establishment and maintenance. Landusers appreciate the technique because it effectively controls soil erosion and prevents loss(throughsurfacerunoff)offertilizersappliedtothecrop.Asanoption,somefarmersplanttreesonorabovethevegetativestrip.Thismaybeduringtheestablishmentofcontourlinesorlater.Thetreesandothercashperennialsprovideanadditionalsourceofincomeatthecostofsomeshadingoftheadjacentannualcrops(Linigeretal.2011;GIZ2012;RayandSimpson2014).

Theperformancesofvegetativetripsaresimilartothoseofstonebunds.Thecanreducerunoffandsoilerosionfrom51%and34%,respectivelywithasignificantincreaseincropyields.Theyalsoprovidefodderforlivestockandmaterialforvariousdomesticneeds(home,beds,energy,etc.). It is fairly simple, cheaper and therefore accessible to poor farmers. The cost ofimplementationisestimatedatUS$100/ha(Hienetal.,2015).

4.8MulchingMulchingisanothertraditionaltechniquethatusuallyinvolvesleavingmilletandsorghumstalksinthefieldafterharvest.Incaseswherearelaycrophasbeenplanted,suchaswatermelon,thestalksservetoreducetheevaporationofremainingmoisturefromthesoilandactsasabarrierand prevents wind erosion, helping trap the thin rich dust carried by the harmattan wind.Throughactionoftermites,thestalksandbranchesarebrokendownandgraduallydecomposeto get incorporated into the soil profile, providing nutrients and improving the soil structure.Whenaccumulatedinasinglelocationandcombinedwithatemporarycoral,thestalksserveasfeed and bedding for livestock, and are effective for restoring infertile patches of cropland.Mulchingcanbecombinedwithanyothererosioncontroltechniquesuchasthecontourstonebundsorgrassstripsandisacentralcomponentofconservationagriculture(Lamersetal.1998;GIZ 2012; Ray and Simpson 2014). But the growing demand for biomass for household andlivestockneedsisalimitingfactorforthistechnique.

4.9SanddunestabilizationStabilizationof active sanddunes is achieved through a combinationofmechanicalmeasures(such as palisades) and biological measures (such as live fences and sowing grass) (Ray andSimpson2014).Thesemeasuresseektostopsandencroachmentandstabilizesandduneson-site inorder toprotect villages, cultivated land, roads,waterwaysandother infrastructure. Inaddition to moderating temperatures and mitigating the impact of wind, benefits of dunestabilization includes increase in: a) soil cover; b) biomass/aboveground carbon sequestrationandstorage;c)animalcarryingcapacityandd)soilfertility,leadingtomoreproductionofwoodandfodder.Thetechnologyiscurrentlyappliedonalarge-scalewithintheNigerRiverbasin.Asestablishment of these systems requires high labor inputs, it makes them unattractive tofarmersinSahel,outsideofdonorfinancedprojects(RayandSimpson2014).

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4.10FarmerManagedNaturalRegenerationAs described by Pye-Smith (2013), the farmer managed natural regeneration (FMNR) orRégénérationNaturelleAssistée(RNA)inFrenchorsassabinzamaniinHausa,alocallanguageinWAS,isapracticewhichinvolvesidentifyingandprotectingthewildlingsoftreesandshrubsonfarmland. FMNR is a systematic regeneration of living stumps and emergent seedling ofindigenous trees, which previously had been slashed and burned in field preparation. Mostsuitable are specieswith deep roots that do not competewith crops and have good growthperformanceevenduringpoorrainyseasons.Itdependsontheexistenceoflivingrootsystemsandseeds.Shootsfromrootsgrowmorerapidlythansaplingsfromseed,andtheymakeupthebulkoftheprotectedwoodymatteronfarmsinsouthernNiger.Farmerswillgenerallychooseabout five of the strongest stems from the stumps theywish to retain on their land, pruningawaytheremainder.Thesestemscanperiodicallybeharvestedtoprovidefirewoodandtimber.Farmerswilloftenallowonestemtodevelopintoafull-sizetree.Thespeciesfavoredvaryfromplace toplace; as does thedensity of trees. Someprojects have advised farmers to keep thenumberoftreesat40/ha,butdensitiesofover150/haarenotunusual.FMNRisasimple,low-costmethodofre-vegetation,accessibletoallfarmers,andadaptedkeepinginmindtheneedsof smallholders. It reduces dependency on external inputs; is easy to practice and providesmultiple benefits to people, livestock, crops and the environment. More broadly, FMNRrepresentsabroadcategoryofpracticesand thusdoesnotadhere to specific, fixed technicalaspects and suitability criteria. There are different FMNR practices for different agro climaticzonesandfarmingsystems(Linigeretal.2011;RayandSimpson2014).

FMNR can be considered as an innovative successful agroforestry system, which made asignificant impact,particularly in theMaradi regionofNiger sinceyearly1980sandultimatelycoveringmorethan50,000ha(Sendzimiretal.,2011;Haglundetal.2011).Overall,thechangesbroughtaboutbyFNMR, including improvedsoil fertilityand increasedsupplyof food, fodderand firewood, have been estimated to be worth at least US$56/ ha each year (Holt andLegroscollard2013).Morefarmersquicklyadoptedthepractice,andfromthosefirst95villages,FMNR has now spread across southern Niger and even into neighboring countries, includingBurkinaFaso,MaliandSenegal.ThesuccessofFMNRhasbeenwidelydocumented.Morethan5millionhaoflandhavebeenrestored,withover200milliontreesre-establishedorplantedinNiger(Rinaudo,2007;Rinaudo,2010;Pye-Smith2013).

Figure5.FieldcultivatedwithFarmerManagedNaturalRegenerationoftreesinNiger(RegionofMaradi).Photo:SavadogoP

4.11Stonebunds-farmernaturalregenerationThisinnovativeexperiencecombinesthestonebundswithFMNR.Thesystemisnewlyidentified

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onlyinSenegal(Kaffrine,Tabacounda,Villigara).Butitseemstobeinteresting.Thestonebundscouldhelpimprovingtheregenerationoftrees.

4.12ZaïtechniqueTheZaïortassaholestechnologyandotherRDLtechnologiesarewelldocumented(Rooseetal.1999; Mekdaschi Studer and Liniger 2013; Ray and Simpson 2014. Traditionally, plantingpitswere used on a small-scale torehabilitate barren land (zipélé in Burkina) and hardpanareas where rainfallcould no longer infiltrate. The promotion of Zaï became popular in theearly1980sinvariouslocationinWAS.Theyaredugbyhand,withtheexcavatedearthformedintoasmallridgedownslopeofthepitformaximumcaptureofrainfallrunoff.Manureisaddedtoeachpitbeforesowing(Figure5).Theimprovedinfiltrationandincreasednutrientavailabilitybringsdegradedlandintocultivation.Thetechnologydoesnotrequireexternalinputsorheavymachineryandisthereforeeasilyadopted.Zaïholesareoftencombinedwithstonelinesalongthecontour to furtherenhancewater infiltration, reducesoilerosionandsiltationof thepits.Grass growing between the stones helps increase infiltration further and accelerates theaccumulationof fertile sediment. Investigationonmany fieldsof theMossi Plateau (northernpartofBurkinaFaso)hasshownarangeofvariationsoftheZaïsysteminrelationtosoiltexture,availabilityoflaborandorganicmatter(Rooseetal.1999).The Zaï can increase crop yields from 50% to 69% compared to untreated fields (Hien et al.,2015).After2to7yearsofaZaïcroppingsystemonabare,crusted,degradedsoil(eutropept),Rooseetal.(1999)foundthatthissystemincreasedtheproductionofbothcerealgrains(from150to1,700kg/ha)andstraw(from500to5,300kg/ha),andalsoreintroducedalargediversityofusefulplants(22speciesofweedsand13speciesofforageshrubs)thatmayhelptheprocessofdegradedsoilrestoration.

Figure5.TheZaïtechniqueforrestorationofdegradedland.Photo:HienandFatondji

Butthemainconstraintof implementingthistechniquecomesfromthe laborneedtodigtheholes. This operation is time consuming.While theperformance improveswith applicationofsmalldosesoforganicand/ormineralfertilizer,theiravailabilityissometimesaconstraintwhenlivestock is not integrated in the system of farmers.Many research efforts tomechanize thediggingoftheholeswithsmalltoolsbyanimaltractionareon-goinginBurkinaandNiger.SomeexperiencesinNigershowedthatthetimeofimplementationcouldreducefrom300hours/hawiththemanualsystemto50hours/hawithmechanizedsystem(Hienetal.,2015).TheZaïtechnologyhasbeenwidelymodifiedandadaptedbyfarmerstothecroppingsystemsindifferentcountries.Twoofthemhavebeenidentifiedwithdifferentvariants.

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4.13Zaï-StonebundsTheZaï-Stonebunds(ZSB)isaninnovativeexperiencedevelopedbyfarmers.Itisacombinationofthetwotechniques:ZaïandStonebunds.Thegoal istotakeadvantageofbenefitfromthetwo technologies to achieve: i) protectionof soil against erosion, ii) rainwaterharvesting, iii)exploiting all advantages of zaï technologies in terms of better use of rainwater, soil fertilityimprovementandiv)bettermanagementofthecroppingsystem.ThissystemiswellknowninBurkinaandNiger.ThesystemisparticularlyusedinNigerintheregionofTahoua.

4.14Zaï-Stonebunds-FarmerManagedNaturalRegenerationMore than the Zaï-Stone bunds, this innovative experience adds framer assisted naturalregeneration(FMNR).ThisexperienceispopularincentralregionsofBurkina,Senegal(Kaffrine,Tabacounda, Villigara), Mali (Kayes, Segou, Mopti) and Niger (Tahoua). The return oninvestmentofthistechniqueisestimatedat63%(Hienetal.,2015).

4.15SemicircularbundsAsthenameimplies,semicircularbunds(SCB)(demi-luneormicrobasininFrancophoneWestAfrica), are earth embankments shaped in as a semi-circle, with the tips of the bunds facinguphill and aligned to the contour (Ray and Simpson 2014; Hien et al., 2015) (Figure 6).Semicircular bunds were initially developed to harvest the runoff water for growing crops.Organic residues (manure, compost) are locally applied in the SCB. The technique is usedsometimesforestablishingtrees,rangelandrehabilitationandfodderproduction.Dependingonthe configurationof the chosen site, the techniquemaybedeployedasa short slopeor longslopecatchmenttechnique.Semicircularbundsarerecommendedasaquickandeasymethodoftreeestablishmentandrangelandimprovement inthesemi-aridareas.TheSCBispopularlyusedinBurkina,Mali,NigerandSenegal.Thetechniquecanincreasecropyieldsby112%(Hienet al., 2015). As for the Zaï technique, many systems of RDL have been developed usingsemicircularbands.

Figure6.Semicircularbundsforwaterharvestingandreductionofsoilerosion.Photo:Fatondji

4.16Agroforestry-SemicircularbundsAs for the Zaï system, semicircular bands can be used to grow trees in the system. Theimprovementofhumidityandsoil fertility (manureorcompostapplication) inthestructureofSCB involves the germination of tree seedlings that coming from manure, compost or from

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winds.Itissuggestedtoselectandprovideassistancetotheselectedtreeseedlings.Then,thesystemcontributes to reforestation.The system iswell known inBurkinaandNiger. SelectingandprotectingthetreeseedlingscanbeconsideredakindofFMNRinthesystem.

4.17Bio-reclamationofdegradedlandsThe bio-reclamation of degraded land (BDL) system has been developed by ICRISAT. It is anintegrated system of RDL with different components, the semicircular bund (SCB) and Zaïstructures,forfoodandvegetablescropsandtrees.TheSCBareusuallyspacedat5x10m.TheareabetweentheSCBisoccupiedbyplantingpitsofzaï.Thevegetablecropsareplantedinthezaï holes, which also collects runoff water. Trenches are dug every 20m down the slope tofurtherharvestrunoffwater.

TheBDL is an innovativeproduction systemof horticulture crops that provides solutions to arangeofcriticalconstraintsaffectingthelivelihoodoftheruralpopulationoftheSudanoSahel.Becauseofitssimplicityanditsmanypositiveattributes,thepotentialforitsmass-adoptionisveryhigh.TheBDLisverypopularinNiger.Becausewomenhavelimitedaccesstolands,manyNGOs and projects are widely using the BDL systems as an alternative to rehabilitate thedegradedlandsforwomenassociations.

Figure7.RegenerationoftreesbythetechniqueofBio-reclamation.Photo:Fatondji4.18AgroforestryparklandsystemsThetraditionalagroforestryparklandsystem(APS)istheoldestsystemofthesemi-aridandsub-humidzonesofWestAfrica.TheAPSismoreasustainablemanagementpracticedevelopedbyfarmersoveryearsthanatypicalRDLtechnique.APSarecroplandareasinterspersedwithself-generating, indigenous tree species. Farmers systematically protect a certain density of treespecies of economic, social or medicinal interest. Among the characteristics of traditionalagroforestry parklands are the diversity of tree species and the variety of products and uses(includingfruits,fodder,etc.).Vitellariaparadoxa,Parkiabiglobosa,andFaidherbiaalbidacerealsystems are common across millions of hectares in the Sahelian zone (Breman and Kessler,1997;Linigeretal.2011;RayandSimpson2014).

5.ConclusionThemaingoalofthisreviewwastomakeaninventoryofthetechnologiesandexperiencesofRDL recorded in literature.Many technologiesandpracticesofRDLhavebeendevelopedandadaptedbyresearchers inWAS.Weidentified18mainsystemsofRDLwithdifferentvariants.Somearedevelopedfromtraditionalpractices.MostoftheindividualtechnologiesorpracticeshavebeenusedtodevelopadiversityofsystemsofRDL.Thediversityoftheinitiativesseemstobeanindicationofthedynamismoffarmers,developmentagenciesandresearcherstoimprovethemanagement, conservation and rehabilitation of degraded lands. The experiences are so

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diversified.SomeinterestingsystemsofRDLareverylocallyapplied.Themostefficientsystemswithsignificantimpactarewelldocumented,suchasthesuccessstoryofthefarmermanagednatural regeneration (FMNR) in Niger. But other systems are emerging combining differenttechnologies including the FMNR. Some interesting systems,which no longer have significantimpact, are fairlydocumented. Even though theyhavenot yetmade significant impact, somenewinnovations,locallyadaptedbyfarmers,needmoreattention.Theyare:i)Zaï+Stonebunds,ii)Zaï+Stonebunds+FMNRandiii)theagroforestrysemicircularbunds(ASCB).

Anextstepistovisitalltheseexperiencesontheground.Throughfieldsurveys,interactionwithactors through focus group discussions, etc., should help in assessing the scope, the socio-economiccontextandopportunitiestoscalingthebestexperiences.Thisreportandtheworkingstrategywillbesharedforvalidationinaworkshopinvolvingallthestakeholders.

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