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Local knowledge and the social shaping of soil investments: critical perspectives on the assessment of soil degradation in Africa

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Local knowledge and the social shaping of soil investments: critical perspectives on the assessment of soil degradation in Africa
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  Land Use Policy 22 (2005) 33–41 Local knowledge and the social shaping of soil investments:critical perspectives on the assessment of soil degradation in Africa James Fairhead a, *, Ian Scoones b a Department of Anthropology, University of Sussex, Falmer Brighton BN1 9SJ, UK  b Institute of Development Studies, University of Sussex, Brighton BN1 9RE, UK  Received 24 January 2003; received in revised form 16 June 2003; accepted 1 August 2003 Abstract This paper explores local knowledge and practices in soil management and investment that have frequently gone unrecognised inassessments of soil fertility transformations and trends. Case material drawn largely from the Guinea savannas of West Africa isused to challenge the assumptions and methods that agronomists have been using to assess soil fertility transformations and trends.It outlines the need for an approach to the study of soil fertility that engages more comparatively with local knowledge, andappreciates the social and moral orders which shape the ways both African farmers and western agronomists use and understandsoils. r 2004 Elsevier Ltd. All rights reserved. Keywords:  Soil; Africa; Local/indigenous knowledge Introduction Issues concerning environmental change have recentlybecome highly polarised. This involves, in part, a newgeneration of work that questions the methods, assump-tions and deductions involved in characterising soilchanges, and that questions the validity and generalisa-bility of the strong conclusions that have been drawnconcerning soil degradation. Yet such critique is notnew. Consider, for example, the radical reappraisal of shifting cultivation forwarded by Nye and Greenland(1960) in the 1950s. Such critique is part of scientificadvance. What is new in this new generation of work,however, is the argument forwarded by some critics thatorthodox views, assumptions and methods in currentresearch into soil degradation are not only problematic,but are shaped by and reproduce wider relations of power.Since the 1960s, the social sciences have been forcedto reappraise how they came to know the cultures andsocieties that they studied across the world. This wasstimulated by struggles for political independence, andthe emergence of critical scholarship among academicsfrom those countries. In the social sciences this wasexemplified in Said’s (1978) classic work,  Orientalism ,that reconsidered how Western academic social scien-tists, and in particular the ‘Orientalists’ who wererepresenting Egypt and the Middle East in their work,came by their truths. Critical scholars did not merelyreappraise colonial social science, but explored howearlier research reflected the institutional and financialrelations of colonialism, and how the truths it estab-lished served to reproduce these relations. This criticaltradition in social science has now expanded to embracethe natural sciences, analysing the way African soils(and forests) and their cultivators come to be proble-matised not simply within soil science, but within thefinancial and institutional world in which soil science isembedded, and that shapes its practice. Thus, whilstthere are now many works that question the continentaland national scale analyses of soil and site degradation(e.g. Stocking, 1996; Mortimore, 1998; Lomborg, 2001), several consider explicitly how these generalisationshave been shaped by the political economy of research(Keeley and Scoones, 2000, 2003; Leach and Mearns, 1996; Fairhead and Leach, 1996), and indeed, by colonial legacies (Grove, 1995). ARTICLE IN PRESS *Corresponding author. E-mail addresses:  j.r.fairhead@sussex.ac.uk (J. Fairhead),i.scoones@sussex.ac.uk (I. Scoones).0264-8377/$-see front matter r 2004 Elsevier Ltd. All rights reserved.doi:10.1016/j.landusepol.2003.08.004  The recent recognition and appreciation of ‘localknowledge’ (sometimes called indigenous, or ruralknowledge) does not necessarily escape this criti-cal tradition. Several appraisals have considered thestudy of local knowledge to involve assessing thevalidity of local agro-ecological beliefs and practices interms of the conceptual apparatus of Western agricul-tural science and economics. Those working from thisperspective understand their work to be evaluating theaccuracy of local knowledge. They have sought to‘empower’ people vis  " a vis scientists and planners whomight only be convinced of local wisdom through such‘solid’ scientific assessment. However important this is,there is an assumption that the agronomic sciences arein a position to evaluate local perspectives. This doesnot allow the possibility that these perspectives mightactually question concepts, methods and assumptionsembodied in Western soil science traditions. Yet soilresearchers openly acknowledge that they have only apartial knowledge about the agro-ecological phenomenawhich underlie resource users’ existing knowledge andpractices. Much research still needs to be conducted.For example, the current TSBF programme researchthemes point to the continued need for research into soilbiota and their manipulation to enhance nutrientcycling, and into synchronisation of nutrient releasefrom organic sources with crop demands. Both of theseprocesses are central to local fertility managementpractices in much of Africa (e.g. Fairhead, 1992).Equally, researchers evaluating the anthropogenic blacksoils of the Amazonian region ( terra preta ) remainunsure of the processes that generate them and renderthem so fertile (Woods and McCann, 1999). Since the1940s there has been sporadic research attention on theways that farmers valorise and direct the activity of different termite species in their fertility management.Progress has been made on understanding the impact of termite fungal cultivators on soil properties and mycor-rhiza, and their impact on nutrient availability and cropgrowth. Are agronomists yet in a position to evaluatelocal experience and knowledge in terms of this research,or are they themselves still learning?Attention to local experience and knowledge alsoreveals an appreciation of the complex and interactingfactors that influence soil fertility, including nutrientstatus, soil structure, water properties, organic matter,acidity, soil fauna and flora. It tempers any tendencytowards reductionism that can be observed, for example,in academic reasoning that gives strong priority to anyparticular factor, such as nutrient balances.Attention to the history of soil science in Africa showsthat farmer perspectives  have  often reshaped scientificinquiry, but that this has been often unrecognised. Fromthe early 20th century, many tropical agronomists drewinspiration from observation of local practices andrationale (e.g. around rice farming), and used this topose new research questions (Richards, 1985). Morerecently, the emergence of research into agroforestryand into intercropping could be examined in this way(Amanor, 2001). Indeed, the current engagement of agricultural sciences with local knowledge has pro-foundly altered contemporary sciences. It has exposedthe pitfalls of exporting temperate sciences to thetropics: of assuming climatic stability on climates whichdisplay extreme variability (e.g. Scoones, 1999; Morti- more, 1998; see Maley, 2002); of assuming ‘equilibrial’ dynamics on non-equilibrial environments (e.g. Holme-wood and Rogers, 1987; Behnke and Scoones, 1993), and of assuming fertility to be linked to soils, and not tosites (Nye and Greenland, 1960), wider landscapes(Scoones, 2001), or timing (e.g. Lansing, 1987, 1999). As the perspectives of African farmers can challengeexpert soil science traditions and assumptions, engage-ments with local knowledges need to be more compara-tive than evaluative; more of a conversation than anassessment.A second critical perspective in local knowledgeresearch starts from an appreciation that researchmethods, concepts and assumptions on which modernagricultural science is grounded (its epistemology) hasbeen conditioned not only by the particular ecologicalcontexts in which it arose, but also by the particularsocial and economic contexts in which it has developed.Assumptions embedded in the world of commercialagriculture can be challenged by those for whomfarming is embedded in very different ways of life, andespecially where farming practices have moral as well astechnical dimensions. Assessing soil fertility through thecalculus of nutrients in which fertility status is under-stood as if it were a bank account, is challenged by thosewho have a wider social calculus on the determinants of soil and site fertility. For example, soil fertility is attimes understood as determined primarily by marshal-ling the labour needed to enable the necessary invest-ments; by the orchestration of irrigation water; by thesocial orchestration of crop and irrigation timing (e.g.Lansing, 1987), and by proper household relations thatensures the social complementarity that leads tosuccessful crop production (Moore et al., 1999; Jacob- son-Widding and van Beek, 1990; Schoffeleers, 1979; Gottleib, 1982).In the above cases, ideas of soil or site fertility areoften couched in what agronomists may consider asmoral, religious, mythical or superstitious frameworks,rather than in ‘technical’ ones. Understanding soilfertility simply through ‘nutrient balances’ wouldoverlook these alternative modes of comprehension.Any crisis in soil fertility may be a crisis in labour, acrisis in morality, or a crisis in investment, rather than acrisis in soils per se. Whilst some agronomists feel thatthe nutrient balance is simply a ‘better’ and ‘moreobjective’ view (Stoorvogel and Smaling, 1993), such ARTICLE IN PRESS J. Fairhead, I. Scoones / Land Use Policy 22 (2005) 33–41 34  self-assurance presupposes that soil fertility should beunderstood as separate from the social, economic andmoral systems in which soils are used. It treats soilfertility simply as if it were a capital reserve that can bedrawn down, added to, and transferred betweenaccounts. Viewed thus, both the soil and its fertilityare treated as commodities. This understanding of soiland its fertility is compatible with neo-liberal ideas of the market, land markets and of traded inorganicfertilizer. Indeed, conceiving of fertility in this way helpsmake the social and economic assumptions of capitalistagriculture appear to be natural, and extends andembeds these views in wider society. Yet it does notnecessarily reflect the way that many African farmersconsider soil and its fertility. So it is not simply thatagronomists need to consider social, moral and eco-nomic orders and their bearing on farm or territorymanagement (which is the norm) but they need to realisethat the ways nature, soils and productivity areconceptualised are a core element of these very orders.Given that these moral orders strongly influence accessto and control over land, labour and capital, land sales,the timing of cropping and fallowing, and indeed theacceptability or otherwise of inorganic fertiliser, they areclearly extremely important determinants of soil ferti-lity. It should not be surprising that understanding of soil fertility itself is linked to them.The comparative approach that is needed if we are totake local perspectives seriously will therefore need alsoto be an exercise in comparative epistemology. It willexpose the economic and social assumptions framingcontemporary agronomic science just as much as thosethat frame the diversity of African perspectives. Atten-tion to such reflexivity will help communication betweenresearchers and farmers.In this paper we explore some cases that exemplify thesalience of both of these critiques, and come to questionframeworks that are increasingly used to consider trendsin African soil fertility and thus to qualify some of thestrong narratives concerning a crisis in African soilfertility. A strong theme of the examples is that Africaninvestments in soil improvement have often beenunrecognised, and that, as a result, African soil fertilityhas been considered more in terms of a ‘loss of srcinalfertility’ (captured in the idea of nutrient mining, e.g. inSanchez and Shepherd, 1997), than in terms of a balancebetween investment and disinvestment.Drawing on case material principally from the forest/savanna transition zone in West Africa, we considerinvestments in rainfed uplands, and then in particularsites, such as valley bottom lands, river banks andperiodically flooded areas with inherently higher levelsof available soil moisture and nutrients due to theirposition in the landscape. The cases are based aroundour own work, but we indicate their wider relevancewithin the literature. In focusing on these situations, theaim is not to suggest that they are in any wayrepresentative of all African soil management practicesand conditions. Rather, the aim is to indicate thatAfrican investments in soil fertility have been system-atically overlooked, and to consider which factorsinfluence the balance between such investment practices,and others that lead to declining land quality. Thishelps give further consideration of the way fertilitystatus of land depends on social, political and economicorders. Agricultural intensification and soil investments The first example draws on African analogues of Amazonian  Terra Preta . Throughout much of Africa,especially in its humid savannas and forest zone, farmersseek out the sites of old villages and settlements forfarming. In the south east of the Republic of Guinea anyshort walk will take a traveller past sites that were onceinhabited, whether they are abandoned villages, hamletsor farm camps. The soils of these ruins ( tombon ) areknown as  tombondu  ( du  meaning soil or land). They areappreciated for farming because their soils have beenenriched over long years of inhabitation from the ash of wood fires, the excreta of humans and domestic animals,and processed crop products. Farmers say that habita-tion and gardening transform soils, making them moreworkable and productive. ‘New’ savanna land ( du-kura )which has never been cultivated tends to be hard, withlow infiltration capacity. Old village sites and theirgardens that are dug, mounded year after year become‘open’, so water can enter. Organic matter from weeds,crop residues, burnt vegetation and everyday wastes isrepeatedly dug into the soils in the vicinity of villagesenriching them and improving their structure—eventheir texture through enhanced termite activity and theimport of clay materials. Over the years, soils cultivatedin this way become, in local vocabulary, ‘oily’, andmature or ‘ripe’. They are softer and easier to hoe, havefavourable infiltration and because they encouragedeeper plant rooting and remain moist for longer, theyallow crops to better resist dry periods. Farmers say thatthe soil of old habitation sites maintains these char-acteristics long after the site has been abandoned(Fairhead and Leach, 1996).While soil improvement through organic matteraccumulation, ‘opening’ and ‘ripening’ is associatedwith settlements and their kitchen gardens, it is notconfined to such sites. Farmers suggest that regularfarming, when it mimics gardening in repeated mound-ing, and enrichment in organic matter and burntmaterial has the same effect. Planting cassava, peanuts,fonio, maize and okra in rotation can ‘ripen’ the soilafter 3–4 years. Farmers say that such a place will‘become like the soils of a ruin’, using  tombondu  as ametaphor for the result of soil change. ARTICLE IN PRESS J. Fairhead, I. Scoones / Land Use Policy 22 (2005) 33–41  35  The transformation of ‘new’ lands into this soil has animportant effect on vegetation cover when they are leftfallow. Ripened soils tend to develop a dense woodyvegetation, ending in semi-deciduous forest. In effect,savanna successions are deflected into forest successionsthat are retained through subsequent fallow cycles(Leach and Fairhead, 1995). According to farmers, thisoccurs for several linked reasons: the favourableenvironment for tree regeneration, reduced desiccationand fire intensity, and the temporary appearance of more palatable grasses that are grazed by wild animals(and termites), and the transformation and stimulationof termite activity. Thus, both old settlement sites and,analogously, improved farm lands tend to establish adistinct forest vegetation in otherwise more humidsavannas.The upgrading of savanna fallows and their enrich-ment through farming is common, at least in WestAfrica. Mitja (1990) and Mitja and Puig (1991) show that, in the humid savannas north of Man in Coted’Ivoire, when farmers cultivate savanna land on slopes(most of the area) under shifting cultivation, there issubsequently an astonishing regeneration. ‘Not only doinhabitants not degrade the region, rather they improveit’ (Mitja and Puig, 1991: 390). Sites initially coveredwith low woody savanna, come to acquire, after 7 yearsof farming and a long fallow of 10–40 years, vegetationwith a more closed, denser tree cover and fertile soilswith favourable infiltration characteristics, with moresurface pores from worm and termite activity. In Benin,Brouwers (1993) shows the establishment of denselyvegetated fallows rich in oil palms in former savannas.Mondjannagni (1969) shows the establishment of forestthicket in earlier baobab-rich savannas, achievedthrough weeding and burning practices. In Togo, Guellyand colleagues show how farmers deflect ecologicalsuccessions to create a forest formation in grasslandsavannas—creating anthropogenic forest fallows(Guelly et al., 1993). In Cote d’Ivoire, upgrading of savannas was observed by Spichiger and Blanc-Pamard(1973) who show the logic behind Ivorian farmers’assertion that ‘where they cultivate, the forest advances’.Elsewhere in Sierra Leone, and in Guinea, farmersupgrade savannas to secondary forest thicket using thesetechniques, also combining intensive grazing and theincorporation of surface organic matter into the soil(Fairhead and Leach, 1998). These soils are ‘waking up’to quote the farmers cited by Brouwers (Fairhead andLeach, 1998); there is a ‘ratchetting up’ of biomass andan acceleration of its turnover leading to increased sitefertility and to more efficient fallows.The farming techniques used to ‘wake up’ impover-ished soils, and to ‘initiate’ and make ‘oily’ soils that hadearlier been dry and sterile, have also been documentedin recent works that show that farmers tend to upgradespecific fields, generally gardens and ‘home fields’,through importing and incorporating organic matterand wood ash, derived from elsewhere in the landscape(e.g. Scoones, 2001; Osbahr, 2001). This can involve concentrating cattle on the field to manure the land,the collection of manure, the addition of hearth ash andthe addition of other sources of compost, even includingold thatch.In several cases, it is the effects of these practices ontermite species and their mounds that would appear tobe important in site transformations. Farmers through-out much of Africa deliberately select land with manyand large termite mounds, for example, in Tanzanian chitemene  and Guinean shifting cultivation farming(Mielke and Mielke, 1982; Fairhead and Leach, 1996). In parts of Malawi, mounds are owned and traded byfarmers where they are valued for gardening (L. Shaxonpers. comm.). In Benin, Iroko (citing Qu ! enum, 1980)notes how an abundance of termite mounds is taken toindicate good soils for cereal farming, and an abundanceof large mounds is considered a prerequisite for highfertility-demanding yam cultivation (Iroko, 1982). Cit-ing (Mercier, 1968), Iroko goes on to note that this doesnot only concern agricultural aspects of fertility, butalso ritual ones. Many agro-pastoralist Fulbe of Beninchoose their encampments in areas with many termitemounds, ‘signalling the presence of the goddess of fertility, of fecundity and of abundance’ (Iroko, 1982,p. 54). There has been considerable research since thecolonial period that indicates the importance Africanfarmers attribute to termites, and the potential fertilityand soil water benefits that certain termite species canbring. Benefits include (a) import of clay material, richin minerals from deep below the surface (10–15m; up to70m); (b) homogenisation of soil horizons and disman-tling of iron pans; (c) improvement in infiltration andwet season air circulation; (d) concentration of lime(calcium carbonates), with farmers breaking up themounds and distributing their soil over their fields insome regions (Iroko, 1982; cf. Laperre, 1971; Lobry de Bruyn and Conacher, 1990; Lal, 1987); (e) the facilita- tion of deep rooting suiting woody vegetation.Methods to directly influence termite activity havebeen observed throughout Africa (although ratherobscurely), whether in Zai farming in Burkina Faso,(Mando et al., 1993), in Sudan (Tothill, 1948) in Sierra Leone (Helena Black, pers. comm.). Such termitemanagement is often indirect (through manipulatingthe ecological conditions in which certain termitesthrive), but it can also be direct, as when Guineanfarmers speak of certain trees and fruits which theyconsider ‘seed’ termite mounds (Fairhead and Leach,2000). Both Mondjannagni (1975) and Iroko (1982) indicate that specific termite species are introduced inWest Africa, stressing that this is a specialist andgenerally secret endeavour. In South America, farmersalso transform soils by transplanting termites to new ARTICLE IN PRESS J. Fairhead, I. Scoones / Land Use Policy 22 (2005) 33–41 36  locations (Anderson and Posey, 1987). Like anthro-pogenically enriched soils, termite-enriched soils of abandoned mounds support specific vegetation, reflect-ing more fertile and more alkaline conditions, whetherin the Sudanian zone of Burkina Faso (Hauser, 1978), orthe forest margin zone (cf. Begu ! e, 1937; Abbadie et al., 1992).Certain trees are considered as ‘good’ in fields, andare nurtured and protected for their contribution to siteproductivity (e.g. Amanor, 1994). Reviewing the wideliterature on this subject is beyond the scope of thispaper. Equally, certain ‘weeds’ are considered ‘good’ byfarmers, and are perhaps best considered as ‘fertilizingintercrops’, as they suppress ‘bad’ weeds, and assist inthe harnessing of nutrient flushes at the beginning of therains. Following weeding, their rapid decay provides atimely re-release of the nutrients to the growing crop(Fairhead, 1990).Importantly, these processes of fertility improvementshould not be understood simply within a ‘zero sum’calculus of nutrient balance in which some land is beingsacrificed at the expense of others. First, there is more tofertility than nutrient balance. There are changes here insoil structure, edaphic qualities, organic matter status,and fauna and flora influence. There are also practicesinfluencing the efficiency of nutrient use. What seems tobe happening is that farming techniques ‘ratchet up’biomass and its turnover, bringing soils into fertility.The metaphors of ‘waking’ them or ‘initiating’ themspeak of such a transformation. Whether throughimproved infiltration and termite activity (and asso-ciated mychorriza?), through the links with deep rootingplants, or through the grazing of cattle on other(perhaps uncultivable) lands, crops are able to accessnutrients from a much larger volume of soil than isgenerally considered. It is plausible, however, that thehigher biomass, turnover and energy of upgraded landsand associated transformation of vegetation soil fauna,flora and pH might actually improve soil nutrient statusin durable ways. This might be linked to (a) improvedN 2  fixation or capture on the site. For example, nitrogenfixing spirochetes live symbiotically within termite gutswhere they fix nitrogen, and provide up to 60% of termite nitrogen, and thus can provide an importantcomponent of the nitrogen cycle (Lilburn et al., 2001);(b) enhanced activity of plant symbionts linked toenhanced nutrient mineralisation (enhanced P deliveryvia mycorrhiza), and (c) greater accessing of nutrientrich subterranean water (via tree roots, termite hydro-logical effects—for example much subterranean water inCote d’Ivoire and Guinea, has high nitrate content (upto 200mg/l (Faillat, 1990)). It is also plausible that oncelands have been ‘woken up’ the resultant agro-ecologicalprocesses could have a positive influence on the widerlandscape (whether in acting as a source of nutrients,soil fauna, and seeds). These are research questions thatremain to be addressed. In all of these examples, farmersare manipulating vegetation dynamics less to improve‘soil fertility’ than to improve site fertility. Moreover,given the transport of organic matter, whether bylivestock, people or water, it is problematic to considerissues of site fertility outside of a landscape-wide frame,and outside of the economic and social issues whichshape the use of the landscape. Niche resources Improvements and investments are to be found inother key resources in the landscape, such as low-lyinginland valley swamps, river banks and flood plains.These areas are often sites of highly intensive produc-tion, where a wide range of high-value crops might begrown. As Scoones (1991) has shown, in many cases lowlying sites require more labour to cultivate and becomemore significant when other sites show reduced produc-tivity, or land pressures result in people seekingalternative, more costly options.At times, considerable investments have been made toimprove and enlarge inland valley swamps, such as inthe humid savannas in south eastern Republic of Guinea. Here, farmers have—over the last century— vastly increased the sizes of their swamp lands. Theliterature on the region assumes that inland valleyswamps exist ‘naturally’, and that swamp farmingmerely involves bringing them into production, andperhaps improving the conditions through irrigation.Yet farmers tell a different story. Much as their swampfarming usually begins with an existing swamp area in avalley, techniques are used to extend the area, level it,and make it more humid. First, farmers direct surfaceand ground-water movements to create, also on thegently sloping swamp margins, the more permanentlyinundated and productive conditions normally found atthe centre of the swamp. They reduce water outflow andraise water levels by fencing water courses, and buildingbanks of earth and plant residues. Reinforced bygrasses, these banks capture floodwaters, and attractsilt and its associated fertility. During cultivation, soil isalways drawn into the swamp from slopes at theswamp’s edge. Each year, the canal that is dug aroundthe edges of the swamp, to irrigate it from its margins, isshifted further into the hillside, expanding the swamparea. Over decades, these practices gradually broadenand level the swamp. Farmers testify that the area of many of their swamps has doubled in recent decades. Inthe area, management also involves considerations of ground-water. Swamps become humid as ground-waterrises. The roots of the tree  Mitragyna stipulosa  areconsidered to enhance this, as they act ‘like pipes’,channelling water into the swamp from the surroundingslopes, or some say, from great depths. Some farmerssuggest that this is enhanced when the roots of the trees ARTICLE IN PRESS J. Fairhead, I. Scoones / Land Use Policy 22 (2005) 33–41  37
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