indigenous views of soil erosion at fandou béri, southwestern niger

Indigenous views of soil erosion at Fandou Beri,

southwestern Niger

Andrew Warrena,*, Henny Osbahra,Simon Batterburyb, Adrian Chappellc

aDepartment of Geography, University College London, 26 Bedford Way, London WC1H 0AP, UKbDepartment of Geography and Regional Development, The University of Arizona,

409 Harvill Building, Box #2, Tucson, AZ 85721-0076, USAcSchool of Environment and Life Sciences, University of Salford, Manchester M5 4WT, UK

Abstract

Soil is being eroded from the village lands of Fandou Beri, in southwestern Niger, at rates of over

30 t ha� 1 year� 1, as measured by the 137Cs method. These figures exceed those that were used to

label the Sahel a ‘‘hot spot’’ for soil erosion. The response to these data in international agronomic

research organisations has been to make large investments in soil erosion research, but this contrasts

with the meagre relative commitment to the problem by local Djerma (Zarma) and Fulani farmers.

Farmers are more concerned about the loss of fertility than the loss of soil, per se, a viewpoint that

embeds decisions about land use and conservation in a much broader decision-making process.

Practices like paillage (laying of millet stalks) could be interpreted as tacit acknowledgement of

erosion, but they have many other purposes. We ask, who is correct in their assessment of erosion—

the villagers or the agronomists? By comparing scientific evidence, local views and measurements of

erosion, we conclude that the farmers’ opinions are a valid contribution to a complex argument that

consists of short-, medium- and long-term issues. Short-term effects are acknowledged by both

farmers and scientists. They include sand blasting of young crops, the burial or exposure of crops by

floods or windstorms, and the removal of organic matter and nutrients. However, the amounts and

values of the losses incurred in these ways are difficult to establish. In the medium term, significant

losses of water- and nutrient-holding capacity only occur where erosion has drastically reduced soil

thickness, but this affects very few fields. We believe that most of the soils in Fandou Beri are deep

sands that can withstand many years of erosion before they lose significant production capacity. The

longer-term issue is whether farmers should be asked to conserve soil for some abstract and distant

purpose? The negative effects of erosion, at whatever scale, must be balanced against the

maintenance of a community that depends on a holistically conceived system of risk-avoidance

0016-7061/02/$ - see front matter D 2002 Published by Elsevier Science B.V.

PII: S0016 -7061 (02 )00276 -8

* Corresponding author.

E-mail addresses: [email protected] (A. Warren), [email protected] (H. Osbahr),

[email protected] (S. Batterbury), [email protected] (A. Chappell).

www.elsevier.com/locate/geoderma

Geoderma 111 (2003) 439–456

agriculture in which erosion may be unavoidable, given the current constraints of labour and the

imperative to get a crop each year in the face of variable and unpredictable rainfall. The imposition of

a rigorous system of soil conservation might threaten the cohesion of the community. Only a more

open and productive debate between the scientific community, the state, and farmers can reach a

more satisfactory framing of the ‘erosion problem’.

D 2002 Published by Elsevier Science B.V.

Keywords: Fandou Beri; Soil erosion; Niger

1. Introduction

An assault on the West African Sahel by drought, desiccation and degradation is said to

be creating one of the most seriously degraded of environments (Gritzner, 1988; Mainguet

and Chemin, 1991; Warren and Khogali, 1992; Warren et al., 2001a). Land degradation is

said to include nutrient mining (Breman et al., 2001) and soil erosion, in which respect the

Sahel has been claimed as a global ‘‘hot spot’’ (Crosson, 1997).

The scientific data on soil erosion in the Sahel, good as they are in global context, are

not yet sufficient to verify these claims (Warren et al., 2001a). Scientific data alone are

insufficient to judge the severity of the problem, as it relates to the requirements and

techniques of indigenous agriculture. Mazzucato and Niemeijer (2000, 2001) are also

sceptical about the evidence for soil degradation in the Sahel. They find little evidence for

worsening degradation in regional crop production data, or in their detailed fieldwork in

specific locations in Burkina Faso.

There are at least four ways to evaluate the role of erosion in Sahelian agriculture at

the village scale. The first is to analyse erosion rates themselves and their effects on

yield, using a wide range of measurement and modelling techniques (such as the EPIC

model), but these have proved difficult to apply to smallholder agriculture (Michels et al.,

1998). Second, resource economics, as deployed by de Graaf (1996) and Kunze (2000),

assesses the monetary value of erosion to a household or individual, and/or the

‘‘willingness-to-pay’’ for soil conservation. This methodology, we believe, has been

inconclusive because of the difficulty of reducing values to money, and making

inferences from aggregate survey data in communities where there is a great variety of

knowledge and practice (Osbahr and Allan, 2002, this issue; Warren et al., 2001a). Third,

is the finer-grained, multi-disciplinary analysis of household behaviour in relation to

erosion, combining surveys with scientific measurements. We have explored this route in

an earlier paper (Warren et al., 2001a), where we showed some data to support the case

that it was the fields of households that had more livelihood options that suffered more

erosion because these farmers relied less on fertile soils for their livelihood. A fourth

approach is the ethnographic analysis of farmers’ own views, assessing their technical

and practical knowledge of erosion through local taxonomies and value systems.

Elements of this ethnopedological approach appear frequently in this special issue of

Geoderma.

The best understanding, of course, comes from cross-fertilisation between all these

approaches and the adoption of multiple research techniques, particularly from compar-

A. Warren et al. / Geoderma 111 (2003) 439–456440

isons of local taxonomies with appropriate science. In this respect, the francophone Sahel

has proved a fertile ground. In Burkina Faso, several studies have successfully combined

economic, ethnographic, and scientific data to produce a rounded picture of how erosion is

perceived and combated, but also how it affects livelihood systems. These include

Reenberg (1994), Reenberg et al. (1998), Batterbury (1998), Gray (1999) and Mazzucato

and Niemeijer (2000). In Niger, they include Baidu-Forson and Ibro (1996), Lamers et al.

(1995), Rinaudo (1996), Sterk and Haigis (1998), Bielders et al. (2001), and Hassane et al.

(2000). Brouwers (1993), and Enyoung et al. (1999) have worked on these issues

elsewhere in West Africa.

We are, indeed combining some of these approaches at our field site, in Fandou Beri.

Our objective in this paper, accordingly, is to compare the opinions of agronomists and

farmers, using a combination of survey and ethnographic research, combined with

scientific measurement of erosion itself.

2. Site and methods

The research reported here focuses Fandou Beri, in southwestern Niger, which is the

same village as that is described by Osbahr and Allan (2002, in this Geoderma Special

Issue). Osbahr and Allan provide details of the location and most of the methods used in

the research reported here. In brief, a set of nested interdisciplinary studies included

studies of soil erosion (Chappell, 1995; Chappell et al., 1998; Warren et al., 2001a,b),

ethnographic work on social and environmental histories (Batterbury et al., 1996, 1999;

Batterbury, 2001), and studies of soil management and fallowing (Osbahr and Allan, 2002;

Osbahr, 1997, 2001).

The measurement of soil erosion at Fandou Beri, however, is central to this paper and

therefore requires more explanation. Our first problem was to choose a technique for

measuring erosion that was appropriate to the issue of village-level impacts. There are

many ways to measure or estimate soil flux, but most are labour-intensive and expensive

(Higgitt, 1991), and few adequately reflect the extreme variations over space and time that

characterise the process, at many scales. Direct measurement, as by sediment trapping,

rarely produces data that adequately cover this variability. Strenuous efforts to overcome

this problem, as by Sterk et al. (1996), are of value in evaluating damage to one crop, but

would be prohibitively expensive to apply to the evaluation of impacts at the scale of the

household (fields rather than plots and runs of years rather than hours or less). For this

mesoscale, we chose the 137Cs technique. Although it is rare to have household data for the

30–40 year period over which this method produces data, there were no readily available

methods that covered intermediate scales.

The 137Cs technique has an extensive literature (see bibliography by Ritchie and

Ritchie, website available 25.10.01). In brief, 137Cs (Caesium-137) is an artificial isotope

that is produced in nuclear reactions. Large quantities were released to the atmosphere by

bomb testing in the early 1960s. They were mixed within each hemisphere and deposited

on soil surfaces by rainfall, after which they were adsorbed to clays in the upper parts of

soil profiles. The present 137Cs content in a soil profile (compared to a reference sample)

gives a measure of soil loss (or gain) over a 30- to 40-year period. Chappell (1999) and

A. Warren et al. / Geoderma 111 (2003) 439–456 441

Chappell et al. (1998) discussed the particular problems of working with 137Cs in

situations like those of Fandou Beri.

Between 1996 and 1997, we sampled and analysed soil samples for 137Cs, collected

using standard sampling methods, from 15 fields, one field each from those of the Djerma

and Fulani households who were the subjects of social surveys (as reported in Batterbury,

2001; Warren et al., 2001a,b; Osbahr, 2001; Osbahr and Allan, 2002). We prepared one

Fig. 1. The case study village in Niger showing location of sampled fields and terrain.


bulked sample from 30 cores in each field, taking this sample to represent the whole field.

Thus, the data are for fields, and not for microerosional patterns within fields or for larger

areas. The locations of the fields are shown in Fig. 1.

3. Results

3.1. Measurements

The results of the measurements of erosion are shown in Table 1. Most of the erosion is

by wind, as reflected by the higher rates on sandy (tassi) soils, which underlie most of the

cultivated land (the local soil terms and the distribution of soil types are explained in

Osbahr and Allan, 2002, this issue). The alarming signs of water erosion in the gullies and

sediment fans on the margins of the low plateaux in fact affect only small areas of

cultivated land. Studies of short-term rates of wind erosion on nearby sites (Bielders et al.,

1998) have produced rates of the same order of the rates shown in Table 1, which, of

course, refer to a 30-year period. The correspondence may be fortuitous, as the results of

short-term studies cannot be taken as confirmation of those at the medium term, but the

correspondence if encouraging, if nothing more.

Table 1

Soil erosion rates on selected fields at Fandou Beri (1997 data)

Field ID Erosion

(t ha� 1

year� 1)

Average Millet

productivity,

1996–1997

(t ha� 1)

Average

percent

field in

fallow

Distance to

field (km)

Area (ha) Local soil

type

F1A 41.09 366 30 0.9 4.1 botogo/

gangani

F3A 41.48 463 30 0.3 1.8 tassi

F4A 44.23 291 20 2.0 3.5 tassi

F5A 40.27 553 80 1.0 1.7 tassi

F6A 38.85 331 0 1.2 6.9 korabanda/

tassi

F7B 37.66 1350 0 1.5 1.3 gangani

F8A 26.43 955 40 1.7 3.7 tassi

F9A 35.28 338 33 1.8 5.1 tassi

F10A 42.73 800 20 0.5 1.2 tassi

F11A 45.28 360 33 0.9 3.5 tassi

F12A 46.46 405 0 0.5 1.0 tassi

F13A 40.06 706 30 0.4 2.6 korabanda/

tassi

F14A 33.12 445 20 0.1 6.4 tassi/

gangani

F15A 38.12 266 0 0.1 3.6 korabanda/

tassi

F16A 41.89 461 10 0.1 6.6 tassi

The locations of the sites are shown in Fig. 1. Explanations of the local soil names can be found in Osbahr and

Allan (2002). ‘‘Distance to field’’ is distance to each field from the family compound.


3.2. The significance of the measurements

In categorisations of erosion data at the global scale, the rates shown in Table 1 are

‘‘severe’’, given the low-relief, and semi-aridity of this landscape and the dominance of

wind erosion. They almost all significantly exceed the predictions of Lal (1993), and it was

these that had stimulated Crosson (1997) to dub the Sahel a ‘‘global hot spot’’ for soil

erosion. However, there are three major reservations to accepting the gloomy picture.

First is the argument that mere rates cannot reveal the significance of the data. They

must be assessed in the context of household farming and economic strategies, which,

moreover, are differentiated among households. When this is done, their severity is much

less apparent (Warren et al., 2001a).

Second, as we have argued for the case of Fandou Beri itself (Warren et al., 2001b),

high rates have little meaning in two situations. The first is where the depth of soil is so

great that the point at which soil depth is critical to moisture or nutrient supply will not be

reached for very many decades. We believe this to be the case for most of the tassi soils in

Fandou Beri. It is true that clay-rich B horizons occur in some of the sandy soils, and may

limit their effective depth in some circumstances, and when exposed these horizons

become gangani soils (Osbahr and Allan, 2002), whose productivity depends very much

on the seasonal rainfall (also discussed by Osbahr and Allan). We discuss the significance

of this process below. The second case would occur if the soil were to decrease in

importance as households diversify out of heavy reliance on the land for meeting their

food needs, as indeed is the current trend, and as seems very likely (Batterbury, 2001).

Third, the relationship between the soil erosion as measured for a field, and the impact

of erosion on the whole ‘farm’ portfolio is not clear. This has several aspects, depending

on scale.

First, we know little of the significance of the within-field patterns that are created by

erosion: this relates to the issue of microvariability and its management. Lamers et al.

(1995), working in two Djerma communities, conducted a small survey in which 69% of

farmer respondents ‘‘attributed growth variations in millet to microtopographical features’’

caused by wind erosion, which they feel was responsible for the small elevations (more

fertile, more vegetation) and depressions (less fertile, less vegetation) in close proximity to

one another on their fields. The details of the management of these emerging patterns are

not clear.

Second, within the strategy for the whole farm, there is the management at the field-by-

field scale of the changing pattern of soil types that is the result of erosion. Osbahr and

Allan (2002) show how farmers plant different types of soil each year so that they will get

a crop whether the season is dry or wet, suggesting that they need a variety of soil types.

Changes in the distribution of soils, created by erosion, therefore must have quite complex

repercussions on farming strategies.

Third, farmers respond differently to erosion according to their age, ethnic, economic

backgrounds and other factors; some intensify agricultural production in combination with

livestock (a ‘mixed farming’ system), some diversify away from farming, some increase

the number or frequency of their absences from the community to earn money elsewhere,

and some do all three. Farmers at Fandou Beri are, therefore, differentiated according to

whether they retreat from agriculture because of erosion (a very small minority); react by


controlling it (another small minority), or accommodate or accept it (the great majority)

(Batterbury, 2001; Osbahr, 2001). The mix of different adaptations to erosion undoubtedly

varies across other Sahelian communities (Batterbury, 1998; Gray, 1999).

We return to some of these points in the discussion below. All are also discussed in

more detail in Osbahr and Allan (2002).

3.3. Farmers’ views on soil erosion

Two distinctions are important here. First, the farmers’ knowledge of erosion has two

sources: their own experience on the farm and on migration, and those of their neighbours

in the village; and opinions gathered from others, such as extension workers (when these

were active in the village some years ago), Peace Corps volunteers (present in this village

in the 1980s), or nearby soil and water conservation projects operating into the 1990s

(Taylor-Powell et al., 1991). This distinction is made by the farmers themselves. The

second distinction, between soil erosion and soil fertility, is made in the scientific

literature, but much less so by the farmers. In short, the farmers conflate the various

elements that contribute to crop growth (such as rainfall, investment, access to ‘assets’ and

nutrients), in which mixture of factors, soil depth, as affected by erosion, is only one

element, and a minor one at that. Thus, to ask them about only one element (erosion) is to

ask for a difficult exercise in reductionism.

These distinctions must be borne in mind when interpreting of the fact that all the

farmers who took part in group and individual interviews at Fandou Beri, both in 1997 and

1998, acknowledged that water erosion and deposition (and the accompanying flooding)

damaged their crops. Approximately 60% of those questioned in 1998 judged that short-

term damage by wind and water was increasing at both field and village level (Osbahr,

2001). These findings agree with those of Sterk and Haigis (1998) who also surveyed

farmers’ knowledge of wind erosion processes and control methods in this region. Some

63% of their sample considered wind erosion as damaging to their cropping systems, while

men in a nationwide survey ranked wind erosion as the third most important environ-

mental constraint behind drought and soil fertility (Bielders et al., 2001). They listed the

pernicious effects as the sand blasting of crops and the burial of seedlings by wind-blown

sand.

It could be argued that the common, if not universal, practice of laying millet stalks

(mulching or paillage) is evidence of the farmers’ awareness and knowledge about wind

erosion, at least about its short-term effects. Some stalks are left after the harvest in

October, and these remain through the dry season. In the preparation for cultivation in

February or April, the remaining stalks are cut and left to mulch on the surface. Branches

from trees and shrubs may also be cut and laid at this time (branchage). Planting is done

round these residues, so that the surface is protected from winds that may be at their most

damaging at this season (Bielders et al., 1998). These practices have indeed been shown in

field experiments to have a considerable control on wind erosion (Bruntrup et al., 1996).

But there are reservations to this interpretation, for there are other reasons for this

practice. First, the laid stalks can be grazed or cut for domestic use (especially near

homesteads). Second, they attract termites, and these are known by the farmers to be great

soil improvers, an observation confirmed by scientific research (Wezel et al., 2000; Mando


et al., 1996). Third, paillage on gangani soils (silty, ‘‘hard soils’’), which are not generally

susceptible to wind erosion, and on which the practice is even more common than on the

sandy, highly erodible tassi soils, also suggests other purposes than wind-erosion control.

The farmers claim that paillage breaks up the hard surface of gangani (which, in fact, may

make them more vulnerable to wind erosion). Besides this, these practices also recycle

organic matter into the soil, even without termites, increasing infiltration (Valentin and

Bresson, 1992; Leonard and Rajot, 1998) and fertility (Wezel and Boecker, 1998).

Buerkert et al. (2000) found that mulch increased yields by up to 73% in soils very

similar to those at Fandou Beri. The effects of residue on weakly buffered soils (such as

these) were found to have improved P availability, decreased peak temperatures (by 4 jC),increased water availability, to have protected seedlings, as well as acting as erosion

control. Branchage appears to benefit production more from the nutrients it introduces to

the soil than from protection from erosion (Wezel, 2000).

The same confusion of interpretation applies to other indigenous practices that have

been interpreted as indigenous forms of erosion control (Manu et al., 1991). The retention

or planting of grasses, bushes and trees between fields, does help to control erosion, but

their primary purpose may be to control conflict over land, by providing markers. Michels

et al. (1998) found that these field boundaries were poor investments, if intended to control

erosion. Fallow rotation also controls erosion (Buerkert and Hiernaux, 1998; Bielders et

al., 1998; Wezel et al., 2000), but here too there are other more important objectives: the

build-up of nitrogen from legumes; the build-up of organic matter for better tilth and

water-holding capacity, and the accumulation of nutrients from dust (Osbahr, 2001; Drees

et al., 1993). The practices of grazing and ‘kraaling’ livestock may well decrease

susceptibility to erosion (Powell and Valentin, 1997; Casenave and Valentin, 1989; de

Rouw et al., 1997), but their more immediate purpose is clearly to increase nutrient content

of the soil, since farmers apply manure preferentially to the less fertile parts of fields

(Lamers et al., 1995; Brouwer and Bouma, 1997).

If we bear in mind the distinctions that we outlined above, we must, however,

acknowledge the ambiguity of the term ‘‘erosion’’ itself, both in our questionnaire, and,

we suspect, in that of Sterk and Haigis (1998). Most of the farmers at Fandou Beri clearly

restricted the use of the term ‘‘erosion’’ to short-term damage by water or wind, which they

could easily see, but not to the slow long-term removal of soil, which is the more general

mode of loss by wind erosion, and which few acknowledged. Those who did acknowledge

long-term problems confessed that they were repeating what was told to them by extension

workers. This is clear in the rhetoric they use in describing long-term issues: ‘less

vegetation cover’; ‘more people in the village working the soil’; ‘increasing permanent

cultivation’; and ‘decreasing lengths of the fallow period’. Some farmers did claim that

there had been a loss in fertility and declining yields on some fields, but not all of them

believed that the decline was attributed to long-term increase in soil erosion. The most

common reason they gave was the constraints on their management. More significant was

the diversity of opinion among farmers about erosion, which reflects differences in their

experiences, the types of soil on their farm, their knowledge networks, gender, and their

social and economic position (Osbahr, 2001).

Many farmers positively disputed the seriousness of erosion in the long term, and

claimed to be confused by what they had been told about it by extension workers. Some


gave evidence that erosion was not serious, for example claiming that rocky patches in

fields (tondu kakasia), outside the stony plateau (laterite, ferricrete, tondu bon), had not

increased in size (we discuss this process below). Others even believed that soil erosion

had decreased because the amount of rain falling on their fields was often less than had

fallen on their father’s fields. More generally, many did not have the negative perception

of erosion that is common among agronomists, claiming that it was a process that

contributed to soil development and spatial microdiversity (an essential part of their

management strategy). They described how the wind carried loose sandy material from

higher areas, exposing the fertile, but ‘hard’ gangani soils, and depositing this loose

material to the lower lying land, building up the sandy tassi soils in that area (a perception

that closely conforms to one scientific assessment of gangani (Chappell, 1995). In a wider

context, the farmers saw land as part of a creative, ‘living’, contemporary process that led

to the genesis of two distinct types of soil, which made possible a farming strategy that

allowed them to cope with the variability and unpredictability of rainfall, this being the

main determinant of fertility (in their view). Bocco (1991) found much the same ideas

about soil in his study of farmers in Mexico. The management of soil diversity is

explained in Osbahr and Allan (2002). Furthermore, the farmers carefully selected soil

conservation and fertility strategies to suit the peculiar circumstances of each field, and

this suggests that local knowledge is important to resolving the constraints introduced by

erosion.

4. Discussion

The opinions among the farmers of Fandou Beri about the long-term effects of erosion

on agricultural productivity are in contrast with the prevailing international discourse

about the Sahel (Higgins et al., 1982; Mainguet, 1998; Mainguet and Chemin, 1991;

Ramaswamy and Sanders, 1992; World Bank, 1996). These opinions are derived from

many sources, one of which is the literature of agronomy, although there is a plurality of

view among agronomists on this issue. The concern for erosion in the agronomic

community, or at least among those who fund and direct it, is nonetheless implied by

the large investment in research into wind erosion and its mitigation made in Niger in past

years by the International Crops Research Institute for the Semi-Arid Tropics (ICRISAT,

once the largest research organisation in the country) and its associates such as the

programmes of the University of Hohenheim and Wageningen University, whose outcome

is a stream of research, as in the papers by Buerkert et al. (1996), Sterk and Spann (1997),

Buerkert and Hiernaux (1998), Lamers et al. (1998, 1995), Buerkert and Lamers (1999),

Bielders et al. (1998, 2001), among others. The Institut de Recherche et Developpement

Niger office (IRD, formerly ORSTOM) has also invested in research on erosion in Niger

and elsewhere in the Sahel (see Casenave and Valentin, 1989; Valentin, 1994; Rajot et al.,

1996; and earlier work summarised in Warren et al., 2001a). This research includes work

on the effects of wind erosion, the effects of mitigation, as from windbreaks (Renard and

Vandenbeldt, 1990; Brenner et al., 1995; Baidu-Forson and Napier, 1998; Michels et al.,

1998), and agricultural extension that conveys concern about the problem (Sterk and

Haigis, 1998). More practical endeavours have included large conservation projects


elsewhere in the country, initiated by organisations including the FAO, USAID, the

European Community, and German Technical Assistance (GTZ).

Despite some excellent research and development work carried out by these and other

organisations, the framing of the problem has serious implications for communities like

those in Fandou Beri. On the one hand, ‘misframing’ could, and indeed has, led to some

inappropriate interventions that have taken insufficient account of local knowledge and

practices, notably when they have reduced—rather than enhanced—flexibility in local

livelihood systems. On the other hand, very costly science might be applied to the wrong

questions about the constraints to production in these agricultural systems, and could

therefore be better targeted and applied. There are three scales at which the a discussion of

these differing viewpoints about soil erosion can be brought together, each with different

kinds and magnitudes of disagreement, and each with a different combination of scientific

and nonscientific elements.

4.1. Erosion and conservation in the short term

It is about the short-term impact of erosion that there is most agreement between

farmers and scientists, but there is neither unanimity nor certainty about the processes,

their effects or the need or effectiveness of control measures. One problem at this scale is

the sand blasting of crops early in the season, which can be a serious problem, as

acknowledged by the farmers and shown by agronomic research (Armbrust, 1984). Crops

are frequently unearthed or lost in this way, and farmers may have to resow up to six times

in a year for this reason or for the reason that crops are lost in dry spells. If it did not

involve great new investments in cash or labour, measures to tackle this problem would

probably be welcomed by farmers.

Another short-term problem is the winnowing of organic matter, clays and nutrients

from the soil. Research has shown that organic matter and nutrients are preferentially

bonded to clays, and that these are both more susceptible to erosion, and more likely to be

removed far from the point of erosion, and thus lost to the local agro-ecosystem (Leys and

McTainsh, 1994). As the fine fractions are lost, the topsoil becomes coarser (as the farmers

observe), so that the remaining soil has less capacity to hold nutrients and water. In Niger

itself, in conditions very like those at Fandou Beri, Sterk et al. (1996) showed that there

was a significant loss of nutrients in wind-eroded material from agricultural fields.

There would be little disagreement between scientists and farmers about the beneficial

qualities of organic matter. If the breakdown products of manure, roots, stover or cut

branches are retained in the soil, they both help to prevent erosion by forming wind-stable

aggregates (Tisdall and Oades, 1982), and act as a store for nutrients (and in the poor soils

in Fandou Beri, this contribution can be significant). Wind erosion is almost certainly a

large part of the explanation for the loss of organic matter over the last few decades, which

is reported (and regretted) by the farmers.

The case concerning nutrients is more complex. Most soil chemists working in Niger

believe that phosphorus is the most important limiting factor in crop production, yet

because these soils are somewhat acidic, phosphorus is rapidly fixed after application.

Thus, phosphorus that is not quickly taken up by a crop is lost to the cropping system

(Buerkert and Hiernaux, 1998), and the subsequent removal by erosion of phosphorus


fixed to clays and unavailable to crops may therefore be inconsequential. The supply of

calcium and potassium, which are other valuable crop nutrients, or at least soil condi-

tioners, may be satisfied by the annual input from Harmattan dust (at least for these low-

input, low-output agricultural systems, Bationo and Ntare, 2000; Herrmann et al., 1996),

so that their subsequent loss in erosion may also not be as serious as may first appear. Only

a careful analysis farm- and field-level nutrient budgets, over several years, would reveal

the answer to these questions, and this has not yet been carried out.

Perhaps more consequential is the extreme difficulty of proving losses to short-term

production from erosion in a system where production depends on very variable inputs of

rainfall and labour, and on the vagaries of attack by pests and diseases (to mention just a

few in a long list of hazards).

The farmers we have interviewed have two sets of strong arguments to support their

case that soil conservation should have low priority in their short-term management

strategies. First, there are arguments that should strike a chord with agronomists. These

concern the costs of conservation. The extra costs of conservation are hard to afford,

especially in terms of labour, which is a very limiting commodity at Fandou Beri (Warren

et al., 2001a,b; Batterbury, 2001). Moreover, erosion seems to be an unavoidable side

effect of the existing risk-averse farming system (see above), and many of the factors that

dictate an individual farming strategy, and accelerate erosion (like rainfall patterns or the

price of fertilisers) are beyond farmers’ control. Farmers are only likely to moderate their

practices if they experience: declining returns for labour, as well as to land; land scarcity;

or decline in their income from sources such as migrant labour and petty trading. None of

these situations really obtains at present, despite the problems that migrants are currently

experiencing in the politically charged environment in Cote D’Ivoire, habitually the main

migrant destination.

Second, there are arguments that may seem stronger to farmers, but harder to accept by

those involved in developing natural resource management projects in the region. These

reside in the farmers’ holistic view of fertility and crop production, in which erosion plays

a much smaller role that it does in the models and worldviews of the agronomists (Osbahr

and Allan, 2002). It can be seen that even at this scale there are ‘scientific’ and

‘nonscientific’ elements in the argument about soil erosion.

4.2. Erosion and conservation in the medium term

By ‘‘medium term’’, we mean processes that become evident in a 5- or 10-year span.

The principal process at this scale is the one in which erosion reduces the thickness of the

soil to the point beyond which it can no longer hold water or nutrients sufficient for crop

growth. This critical depth has undoubtedly been reached in some soils at Fandou Beri,

and more could succumb quite soon. However, as we described above, farmers we

interviewed believed that this was occurring on only a few fields, and it probably only

affects soils that are already degraded, and whose loss does not yet endanger the

agricultural production as a whole (Warren et al., 2001b).

The debate at the medium term must grapple with many uncertainties. The question is:

are the soils that are being lost by erosion, essential to any of the likely futures for Fandou

Beri? Indications of these futures can be sought in the changes in the present agricultural


systems of the village. For example, there was a great increase in investment in livestock

in 1998–1999; there has also been a steady increase in the exode, or labour migration; and

in intensification of cultivation over last 20 years as shown by air photographs, changes in

fallowing practices, and levels of investment in labour (Osbahr, 2001). There would be

little need in any of these evolving futures to nurture or restore the poor soils that are being

lost, because the income derived from exploiting them now or in the recent past may well

be better invested in a wider, diversified portfolio of activities that will be much more

profitable to households in the future.

A more critical issue is the effects that a strong demand to conserve these soils, issuing

perhaps from future development institutions and extension service activity (although

these are presently quite few in this part of Niger) could have on the viability of farming

enterprises. The prevailing risk-avoidance strategies among farmers (discussed by Osbahr

and Allan, 2002), inevitably lead to exposure of soil to damaging early-season storms,

despite the deployment of paillage and branchage on some fields. The clearing and

exposure of new land—and Fandou Beri does still have land available through loaning

arrangements—is cheaper and easier to do than making investments either in artificial

fertilisers (which are beyond the means of all but a few), or in deploying more labour

(frequently hired) for conservation practices or land rehabilitation. Bielders et al. (2001)

found that most farmers perceived the planting of windbreaks to be a most effective wind

erosion control technique. But because planting grasses and trees required seedlings, local

agreements, protection from animals, and because trees could harbour birds and other

pests, the planting of windbreaks is far less common than paillage and similar low-input

measures. Although NGOs and development agencies are increasingly wise to the need to

design interventions that are appropriate in the context of the whole livelihood system

(rather than selectively treating an issue like soil conservation or credit provision in

isolation), it is still quite unlikely that the policies that would enable soil erosion to

continue at present levels would be viewed as desirable, by organisations like the Peace

Corps or other NGOs and bilateral agencies. To challenge investment in soil conservation

by letting erosion happen would be to attack a sacred cow of much rural development

activity in the Sahel—that conservation is preferable to overexploitation of local ‘natural

capital’ and land-based resources.

The scientific contributions to the debate at this temporal scale include achieving a

better understanding of the long-term rate of soil erosion (as from our measurements) and

models of future soil flux, to predict, for example the ‘‘life’’ of various soils suffering

various erosion rates. It is also important to have a better grasp of the economics of

farming in these conditions, which means understanding the medium-term futures

envisaged by the villagers, and the capacity of households to respond to the challenges

they face on a daily basis, often without much external support.

4.3. The long-term: sustainability

We have attempted to open the discussion on the broad issues of sustainability in

Fandou Beri, as it concerns soil erosion, elsewhere (Warren et al., 2001b). In brief, we

argued that the case for ‘‘strong sustainability’’, in which erosion is minimised or

eliminated, is unfeasible at Fandou Beri. ‘‘Sensible sustainability’’ in which some loss of


soil (as ‘‘natural capital’’) is traded against the benefits this may bring in the form of

accumulation of other forms of capital (for example, human (labour) or social capital),

seems the only option, and may indeed be what is occurring in the community.

Nonetheless, this judgement cannot be verified, because of the lack of rigorous criteria

for the identification of ‘‘sensible’’ sustainability. Under this banner, some erosion might

be condoned, but the principal question at this temporal scale is: should Djerma farmers

really be asked to conserve soil for a long-term future that is very uncertain? The

scientific arguments in this debate are many, and include speculations about global

climate change and its regional variability (Nicholson, 2001). There are also some

interdisciplinary questions about how long-term population–society–environment

dynamics may evolve (Raynaut, 2001). A clearer view of these futures will depend in

part on better understanding of the history of transformations of the Sahel over the last

few centuries.

5. Conclusion

At Fandou Beri, as in much of the Sahel, soil erosion must be seen, as the farmers see it,

in the context of much more pressing agricultural problems such as poor soils, unreliable

rainfall and uncertain political and economic environments. Household strategies accom-

modate themselves to these circumstances by retaining great flexibility, both in terms of

agricultural practice, and through resort to other sources of income. Strategies are attuned

to the vastly variable circumstances of particular years and particular households. Soil

conservation can, and perhaps should, only be a small element in the overall agricultural

system, as many farmers believe. But, at whatever scale, a soil conservation strategy, if felt

necessary for some national or global purpose, could only succeed if it took into account

the opinions and circumstances of those who would be asked to implement it, and who

would in theory be the main beneficiaries.

One way to bridge the evident gaps in understanding about erosion between the policy

and scientific communities on the one hand and the farmers on the other, might be a form

of the local farmer-dominated committees in the evolving Australian ‘Landcare’ system.

These now control the expenditure on the scientific research that concerns their systems of

agriculture (Leys, in press). Leys describes the debates that follow as lengthy and at times

acrimonious. There have been disagreements about the significance and extent of natural

processes, like erosion, and also, as at Fandou Beri, about views of the future. Any such

process would need to reach a balance between current traditional structures of authority

and inclusive participatory formats, a challenging task. Nonetheless, Leys believed that in

New South Wales at least, this process was directing research more effectively than the

top-down model of research it had replaced.

In Fandou Beri, the debate might begin with an admission by the scientific community

that there are still very many uncertainties in the argument about the importance of soil

conservation, and that the farmers’ indifference, at least to its long-term effects is almost as

justifiable on the scientific evidence as is the agronomists’ and policy-makers’ anxiety.

The debate would then focus on research that might resolve the divergences; for example

into the evaluation and adaptation of crop residue and vegetation management techniques,


rather than more costly measures that requiring external aid and support, like windbreaks

and fertilizers (Bielders et al., 2001). Our discussion above shows that, in detail, there are

many issues on which there is agreement between farmers and agronomists, and many

more on which, we believe, further debate could be fruitful. The existing studies of local

knowledge of soils and agriculture in the Sahel (some of them quoted above), could be

seen as a start in this direction, although most have so far been less of a debate, let alone a

radical approach to the application of science, than a collection of localised case studies

with diverse methods and goals.

Acknowledgements

We thank the Economic and Social Research Council (UK) who funded most of the

research reported here through the Global Environmental Change programme

(L320253247, L320223003), and research student grants and the Natural Environment

Research Council (UK) for a research studentship to Adrian Chappell. Henny Osbahr was

funded by a research grant from the ESRC (R0042973459). We also thank Joe Tabor, the

editors of this special issue, the people of Fandou Beri, and our research assistants Nik

Taylor, Siddo Senyi and Micha Weigl.

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indigenous views of soil erosion at fandou béri, southwestern niger

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