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Agricultural success from Africa: the caseof fertilizer tree systems in southern Africa(Malawi, Tanzania, Mozambique, Zambia andZimbabwe)Oluyede Clifford Ajayi a , Frank Place b , Festus Kehinde Akinnifesi a &Gudeta Weldsesemayat Sileshi aa World Agroforestry Centre , PO Box 30978, Lilongwe 03, Malawib World Agroforestry Centre , PO Box 30677, Nairobi, KenyaPublished online: 08 Jun 2011.
To cite this article: Oluyede Clifford Ajayi , Frank Place , Festus Kehinde Akinnifesi & Gudeta WeldsesemayatSileshi (2011) Agricultural success from Africa: the case of fertilizer tree systems in southern Africa (Malawi,Tanzania, Mozambique, Zambia and Zimbabwe), International Journal of Agricultural Sustainability, 9:1,129-136
To link to this article: http://dx.doi.org/10.3763/ijas.2010.0554
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Agricultural success from Africa: thecase of fertilizer tree systems in southernAfrica (Malawi, Tanzania, Mozambique,Zambia and Zimbabwe)Oluyede Clifford Ajayi1*, Frank Place2, Festus Kehinde Akinnifesi1 and Gudeta Weldsesemayat Sileshi1
1 World Agroforestry Centre, PO Box 30978, Lilongwe 03, Malawi2 World Agroforestry Centre, PO Box 30677, Nairobi, Kenya
In response to the declining soil fertility in southern Africa and the negative effects that this leads to, such as food
insecurity besides other developmental challenges, fertilizer tree systems (FTS) were developed as technological
innovation to help smallholder farmers to build soil organic matter and fertility in a sustainable manner. In this paper,
we trace the historical background and highlight the developmental phases and outcomes of the technology. The
synthesis shows that FTS are inexpensive technologies that significantly raise crop yields, reduce food insecurity
and enhance environmental services and resilience of agro-ecologies. Many of the achievements recorded with FTS
can be traced to some key factors: the availability of a suite of technological options that are appropriate in a range
of different household and ecological circumstances, partnership between multiple institutions and disciplines in the
development of the technology, active encouragement of farmer innovations in the adaptation process and
proactive engagement of several consortia of partner institutions to scale up the technology in farming communities.
It is recommended that smallholder farmers would benefit if rural development planners emphasize the merits of
different fertility replenishment approaches and taking advantage of the synergy between FTS and mineral fertilizers
rather than focusing on organic vs. inorganic debates.
Keywords: agricultural innovation; agroforestry; development partnership; research for development; soil fertility;
Background of the problem addressedby technological innovationLow soil fertility is widely recognized as a majorobstacle to improving agricultural productivity in sub-Saharan Africa (Sanchez, 2002). In most regions ofAfrica, soil fertility degradation is caused by threeinterlinked factors: (i) the breakdown of the traditionalfallow system as a result of an increase in humanpopulation and decreasing per-capita land availability,which forced farmers to crop continuously andencroach on marginal lands in search of more fertilelands; (ii) inadequate adoption of soil managementinvestments such as conservation or crop residue
incorporation; and (iii) sub-optimal use of fertilizersby a majority of smallholder farmers due to highcost and constraints to access them. The situationbecame more challenging after the removal of farminput subsidies and the collapse of para-state agricul-tural inputmarketing agencies beginning in the 1980s.For example, after the removal of fertilizer subsidiesin Zambia, the price ratio of nitrogen and maizewent up by 400 per cent, resulting in a 70 per centdecline in fertilizer use by smallholder farmers(Howard and Mungoma, 1996).Given the strong linkage between soil fertility and
food insecurity, addressing the decline in soil fertilityremains an important challenge for those faced withformulating Africas development policy agenda
*Corresponding author. Email: firstname.lastname@example.org
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(NEPAD, 2003). There is a need for technologicaloptions that replenish soil fertility as quickly as poss-ible for a range of ecologies and agricultural systemsand that are suitable for different types of farm house-holds. Fertilizer tree systems (FTS) are one option thathas been developed to meet such challenges.
Description of the technological innovationFTS [The term fertilizer tree system does not implythat the trees provide all the major nutrients: they arecapable of fixing only N, which is the most limitingmajor soil nutrient. The trees can recycle the soilsphosphorus (P), calcium (Ca), magnesium (Mg) andpotassium (K), but these macronutrients must besourced externally when they are highly depletedfrom the soil.] involve the planting or regenerationof fast-growing nitrogen-fixing trees or woodyshrubs that produce high-quality leaf biomass, andare adapted to the local climatic and soil conditions(Kwesiga and Coe, 1994; Akinnifesi et al., 2008).The principle underlining the concept of FTS comesfrom the fact that although nitrogen is the most limit-ing macronutrient in the soil, it is highly abundant inthe atmosphere. Through biological nitrogen fixation,trees replenish the soil fertility by transforming atmos-pheric nitrogen and making it available in the soil.Depending on the species, trees grow for one ormore years, after which they are cut down and thebiomass gets incorporated into the soil. When thetree biomass decomposes, it releases nitrogen forcrops use, thus replenishing the soil fertility andimproving crop productivity. FTS help farmers toproduce the needed plant nutrients by using landand labour instead of cash, which most farmers lack.Over the years, different types of FTS have
been developed including sequential fallows,semi-permanent tree/crop intercropping, annualrelay cropping and biomass transfer. To ensure sub-stantial contribution in terms of amount of nitrogenfixed and biomass production, the choice of FTS pro-moted in a given area takes cognisance ofagro-ecology and soil conditions. Technical detailsof FTS have been documented elsewhere (Mafongoyaet al., 2006; Akinnifesi et al., 2010).
Who developed the technological orinstitutional innovation?Diagnostic research identified the key obstacles toagricultural production and farming systems in theregion. In particular, nitrogen was identified as the
most important missing nutrient and this lack of nitro-gen is responsible for low yields of maize, the stapleand politically strategic food crop in the region.Given that farmers in the region do not traditionallyplant trees to improve soil fertility, an ethno-botanicalsurvey was carried out to establish an inventory ofindigenous tree species that grow quickly to amasssufficient biomass, tolerate periodic droughts orwaterlogging and survive under nitrogen-limitingconditions. The initial attempts to fertilize soilsusing trees through the alley cropping techniquewere discontinued because the technology did nottechnically fit in parts of the region (Ong, 1994).Efforts were then directed to research on improvedtree fallows and modification of the alley croppingconcept to improve the performance of nitrogen-fixing trees in a semi-permanent intercroppingsystem. Research on FTS was initiated in the late1980s through the collaboration of researchers fromthe World Agroforestry Centre (ICRAF) and nationalagricultural and forestry institutions in four southernAfrican countries: Malawi, Tanzania, Zambia andZimbabwe. Improved (sequential) fallows weredeveloped and first tested in Zambia (Kwesiga andCoe, 1994). Annual relay fallows and Gliricidiamaize intercropping were both developed and werefirst tested on-station and on-farm in southernMalawi (Akinnifesi et al., 2008).FTS on-station experiments conducted in the early
1990s showed promising results of increasing cropyield through Sesbania sesbanwith orwithout the appli-cation of mineral fertilizers (Kwesiga and Coe, 1994).To avoid the potential genetic risk associated withusing only one plant species and to diversify optionsto meet the preference of different typologies of house-holds, other plant species and provenances were evalu-ated alongside Sesbania. These include Cajanus cajan,Tephrosia vogelii and Tephrosia candida, which aredirectly sown and hence save labour inputs on nurseryestablishment and transplanting. The others are Glirici-dia sepium, Leucaena spp., Calliandra calothyrsus andAcacia spp. The work on a treecrop intercrop systemusing G. sepium was developed by ICRAF in southernMalawi to address small landholding size (Akinnifesiet al., 2010). It is a modification to address key short-comings that affected crop performance, includingeliminating the hedge competition effect. It allowsconcurrent cultivation of trees with crops during farmseasons and fallow during off-season up to 20 yearswithout replanting (Akinnifesi et al., 2008). It is cur-rently the fertilizer tree species most preferred by small-holder farmers in Malawi.
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What partnerships helped?The development of FTS was based on multi-institutional and cross-disciplinary partnership andcollaboration between researchers and farmers. Overtime, researchers placed increasing emphasis ontesting FTS under the realities of farmers fields andincreasing the involvement of farmers as key partnersto refine and develop the technology further.Researchers began to test the technologies on-farmand involve farmers as partners in the process insouthern Africa in the late 1980s. The first set ofon-farm testing was designed and wholly managedby researchers (Type 1 trials). The second stage ofon-farm testing of FTS was designed by researchersbut managed by farmers (Type 2 trials). In the thirdstage, on-farm testing was wholly designed andfully managed by farmers (Type 3 trials).At national and sub-national levels, two major part-
nerships were formed in the course of development ofthe technology. One was the adaptive participatorytrial, which focused primarily on ensuring collabor-ation with farmers in on-farm trials of FTS. Theother partnership was a network of key stakeholdersinvolved in FTS drawn from government and non-government institutions. These were christened asConsultative Forum on Agroforestry in Zambia,National Agroforestry Research and DevelopmentForum in Malawi and National Agroforestry Steer-ing Committee in Tanzania and Zimbabwe.Members of the network met once a year to reviewactivities from the preceding year, share researchresults and experiences regarding field performancesof FTS, and plan for the coming year.More recently, through the Agroforestry Food
Security Programme (AFSP) currently beingimplemented in Malawi, ICRAF has been scaling upthe testing and dissemination of fertilizer trees withmore than 20 Research for Development stakeholdersin Malawi since 2007. In this scaling-up approach,stakeholders undertake annual joint planning andbudgeting and implementation in 13 agricultural dis-tricts. ICRAF provides research and science backstop-ping, training and information, and ensures qualitygermplasm provision.
To what extent was social capitaldevelopment a part of the project?Following one cycle of researcher-managed exper-imentation, a constructivist approach was adopted,that is, farmers were encouraged to experiment andshare their experiences with the technology. Muchof the training and planning took place through
farmer groups, which were important for colla-borative nursery management. From research andfarmer findings, it became apparent that efforts mustbe focused on shortening fallow period, identifyingcheaper methods of plant establishment and encoura-ging wider farmer participation in technology devel-opment and adaptation. As a result, farmers madeseveral modifications and adaptations based on theirexperiences (Kwesiga et al., 2003; Akinnifesi et al.,2008), including
intercropping maize with trees during the first yearof tree establishment to reduce the waiting periodbefore trees start to impact on soil fertility;
using bare-rooted seedlings instead of the rec-ommended potted seedlings, to reduce labourinputs; and
pruning Gliricidia simultaneously with weedingrather than performing these two operationsseparately.
The details of these innovations have been documen-ted elsewhere (Katanga et al., 2007). In addition, inrecent years, studies have been carried out to obtainsystematic feedback about FTS through a betterunderstanding of farmers knowledge, attitude andpractices on soil fertility FTS (Ajayi, 2007).
The number of farmers adopt...