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Nutrient Management and Farmers' Concept of SoilFertility and Fertilisers: A Case Study in SouthernVietnamA. Hedlund a , E. Witter a , M. H. Hoang Fagerström a & Bui Xuan An ba Department of Soil Sciences, Swedish University of Agricultural Sciences, PO Box 7014,SE-750 07, Uppsala, Swedenb Department of Animal Husbandry, University of Agriculture and Forestry, Thu Duc, HoChi Minh City, VietnamVersion of record first published: 26 May 2011.

To cite this article: A. Hedlund , E. Witter , M. H. Hoang Fagerström & Bui Xuan An (2004): Nutrient Management andFarmers' Concept of Soil Fertility and Fertilisers: A Case Study in Southern Vietnam, International Journal of AgriculturalSustainability, 2:3, 180-189

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Nutrient Management and Farmers’ Concept of Soil Fertility andFertilisers: A Case Study in Southern Vietnam

A. Hedlund1, E. Witter1, M.H. Hoang Fagerstrom1 and Bui Xuan An2

1Department of Soil Sciences, Swedish University of Agricultural Sciences, PO Box 7014, SE-750 07 Uppsala, Sweden;2Department of Animal Husbandry, University of Agriculture and Forestry, Thu Duc, Ho Chi Minh City, Vietnam

Nutrient management in Vietnam was exposed to major

changes with the introduction of the reform policy (‘doimoi’), which entailed the introduction of new crops andnew fertilisers and increased consumption of mineral

fertilisers, leading to higher yields but also possibly tohigher losses of nutrients to the environment.However, sustainable nutrient management optionscan be developed through merging scientific and local

concepts. Participatory methods were used to gatherinformation about the farmers’ concept of soil fertility,the fertilisers available and their features, and the infor-

mation available. The farmers’ concept of soil fertilitywas more directly connected to the ability of thewhole system to promote good yields than the scientific

concept of soil fertility as the soil’s ability to deliver suf-ficient nutrients and water to the plant. The farmers’concept of fertilisers included a wide range of amend-

ments that were added to promote good conditions forplant growth, rather than to provide nutrients for thecrop. The study revealed an information systemwhereby some innovative farmers were the keys to

other farmers’ access to external information on nutrientmanagement. The results show that any attempt madeby outsiders to improve nutrient use efficiency must

be applicable to the farmers’ concepts.

Keywords farmers’ concepts, fertiliser, nutrientmanagement, peri-urban, PRA/RRA-methods,soil fertility, Vietnam

Introduction

Nutrient management is just one aspect of farmmanagement and has to be seen in the context offarmers’ struggle to adjust investments in cropand livestock production to the needs, know-ledge, interests and health of all members of thehousehold. Furthermore, agricultural productiontakes place in an unpredictable environmentwhere weather, pests, market and legislation

often give rise to surprises and new challenges.After the government of Vietnam introducedthe reform policy (‘doi moi’) in 1986, farmersexperienced dramatic changes in both legislationand the way their markets operated. This processwas further enhanced by the lifting of the USembargo in 1994. The reform comprised de-collectivisation of agriculture and elimination ofmost subsidies and price controls. The openingup of the economy entailed the introduction ofnew crops and fertilisers, and resulted in theconsumption of mineral fertilisers in Vietnamincreasing by 350% between 1990 and 1999(FAO, 2000). This development was most pro-nounced in many peri-urban areas and thedensely populated river deltas (the Red Riverdelta and the Mekong River delta). The reformpolicy has offered new opportunities to thefarmers, but has also put new demands onfarmers’ knowledge and ability to adapt. Mostorganic waste products and wastewaters weretraditionally recycled to agricultural land inVietnam (Nguyen van Bo, 2001), but nowadaysfarmers’ interest in using human and animalmanures has decreased due to the increasedavailability of cheap chemical fertilisers and adecreased availability of farm labour. The some-times excessive use of chemical fertilisers,together with heavy use of pesticides, mayresult in contamination of groundwater andsurface waters through leaching and runoff(Richter & Roelcke, 2000).

There is growing concern about the risk of con-tamination of waters, soils and agricultural pro-ducts in rapidly urbanising areas of Asia due toheavy, or inappropriate, use of organic wastes,fertilisers, pesticides and poor quality irrigationwater. For example, a nutrient balance study inthe village of An Son, southern Vietnam,

INTERNATIONAL JOURNAL OF AGRICULTURAL SUSTAINABILITY Vol. 2, No. 3, 20041473-5903/04/03 0180-10 $20.00/0 # 2004 A. Hedlund et al.

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showed that plant nutrients were apparentlyadded in great excess, indicated by a nutrientsurplus (the balance between nutrient input andnutrient removal in harvested products) of upto 1736 kg N, 1292 kg P and 913 kg K ha21 peryear (Hedlund et al., 2003). These yearly sur-pluses seem agronomically unwarranted andincrease the risk for contamination of waterresources. Fertiliser demand is determined byfarmers’ perception of the role different types offertilisers can play in enhancing soil fertility andcrop production, which may be based on a para-digm of input expansion. The results of Hedlundet al. (2003) clearly suggest the need for a movetowards increased nutrient input use efficiency,especially in peri-urban areas. Peri-urban areasof the tropics also represent a new and challen-ging domain for applying farmer participatoryapproaches because the pace of change isfast and interactions amongst producers andconsumers are more immediate, creating abroad stakeholder base to which impacts ofdecisions are visible (Pretty, 1995).

The main objective of this study, which wascarried out in a peri-urban area outside Ho ChiMinh City in southern Vietnam, was to gain aninsight into some of the perceptions of farmersthat lie behind the decisions they make in nutri-ent management. Another objective was tostudy sources of external information in soil man-agement, in order to understand other factorsimpacting on farmers’ decisions.

Materials and Methods

Site description

The study was carried out in the village of AnSon (118N, 1068E), Thuan An district, BinhDuong province, southern Vietnam. Fieldsurveys were conducted from July to September2000. An Son has 1100 households, of whichabout half derive their main income fromfarming activities. The study village is situated30 km north west of Ho Chi Minh City on aflood plain of the Saigon river (0.5–2 m abovesea level), and consists of five hamlets (An Phu,An Quoi, An My, An Hoa and Phu Hung). Theclimate is tropical with an average yearly pre-cipitation of approximately 1900 mm (Personalcommunication Vo Khac Tri, 2000, Southern Insti-tute of Water Resources Research). Due to its lowaltitude, the village is protected by a dyke system

and the land is drained by a network of canalsand ditches which also serve as an irrigationsystem during the dry season. Some floodingevents occur every year during the rainy season,but usually last for no more than two to threedays. Depending on altitude and land use, thesoils are classified as sulfic endoaquents or sulfa-quents (Soil Survey Staff, 1999) implying that thesoils have a pyrite layer at a depth of between 30and 45 cm. This pyrite layer in combination witha watertable at about 40 cm makes the soils acidicdue to oxidation of the sulphidic material (vanBreemen, 1982). Soil pH varies between 3.9 and6.6 (Hedlund et al., 2003) and the crops have ashallow rooting depth (approximately 15–40 cm).

Farm size in the study village is in the range0.09–3 ha, and the crop systems in the studyarea consist of annual and/or perennial crops.The annual crops are rice (Oryza sativa L.),sugar cane (Saccarum spp.), taro (Colocasia anti-quorum S), maize (Zea mays L.), and differentvegetables. The perennial crops are various fruittrees, for example citrus bushes (Citrus spp.)and jasmine (Jasminum multiflorum L.). The mostcommon livestock system is pig production forproduction of piglets or fattening pigs. Thefarmers mostly sell their products to localmiddle-men. Off-farm employment opportu-nities as farm labourers or factory workers arealso easily available. The village is served by theextension service centre in Binh Duong province.The extension service centre operates in thevillages through extension clubs; the one in AnSon has around 40 members. The extension cluborganises about 10 meetings every year coveringvarious agricultural issues.

Participatory Rural Appraisal/Rapid RuralAppraisal (PRA/RRA) methods

The PRA/RRA study was carried out in threeparts. The first part provided background dataon the farming systems in the whole village.The aim was to identify the dominant crop and/or livestock systems in the village. This wasdone in group meetings in each of the fivehamlets with groups of seven to 13 well-informedfarmers who were willing to participate. Thecharacterisation procedure is further describedby Hedlund et al. (2003).

Part two involved the identification of soilfertility problems in the village, which wasdone at the same time as the identification offarming systems, but only in three of the

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hamlets: Phu Hung, An Phu and An Hoa. Thefarmers identified problems with soil fertility(kho khan dinh duong dat trong), which were laterorganised into problem flows, from root causesto effects. The farmers were also asked tosuggest solutions to the problems identified(results not shown).

The third part of the study dealt with thefarmers’ perception of fertilisers and appraisalof information sources. Four group meetingswere held with farmers in which each group (ofsix to nine farmers) represented each of the fol-lowing farming systems: annual crops; annualcrops in combination with pig production; peren-nial crops; and perennial crops in combinationwith pig production. These represent the mostcommon types of agricultural production in thisarea (Hedlund et al., 2003).

Scoring procedures were used to assess thefarmers’ perception of fertilisers. To identify thefertilisers most used, the farmers were asked tolist the fertilisers (phan bon) they have access to.The list of fertilisers was then written across thetop of a sheet of paper and each farmer allocateda number of maize seeds to each fertiliser toreflect how much they used each fertiliser. Thisscoring procedure resulted in a ranking list ofthe fertilisers most used for each group offarmers. The same procedure was repeated withregard to the criteria the farmers used in orderto select fertilisers. The criteria were then listedon the left-hand side of the paper, forming acriterion � fertiliser matrix. The farmers in thegroups scored, individually, the different attri-butes for each fertiliser by allocating a numberof maize seeds by the side of the criterion. Thisprocedure resulted in a summary of thefarmers’ perception of the characteristics ofdifferent fertilisers, which was further discussedin the groups. A similar procedure was used byGold et al. (2002) in a farmer participatory apprai-sal study when assessing selection criteria ofMusa cultivars in Uganda.

Pair-wise ranking was used to assess thefarmers’ appraisal of different informationsources. The information sources listed by thefarmers were compared in pairs. Each time apair of information sources was compared, thesource judged to be the most trusted was givena score. The information source receiving mostscores was judged to be the most trusted.

In parallel with the group meetings, a studyusing the ranking method was carried out withseven representative individual farmers to

obtain a better understanding of farmers’ con-cepts regarding the quality of plant nutrientsources. To cross-check, fill information gapsand to complement the problems identified, agroup meeting was held with key informants,including all hamlet leaders and vice hamletleaders, who were all experienced farmers. Forthe same reason, semi-structured interviewswere carried out with three fertiliser retailers,two fertiliser agents and one extension workerin the area.

The PRA/RRA team consisted of one Swedishsoil scientist and one Vietnamese animal husban-dry scientist, who also acted as an interpreter. Allthe group meetings were held in the homes ofindividual farmers. The participants were noti-fied a day before the meetings. Written recordswere kept by the researchers.

Results

Farmers’ perceptions of problems connectedto soil fertility

The problems identified by the farmers couldbe classified into three major groups; acidity,market and flooding. The most importantproblem perceived by the farmers was themarket. When asked about problems experiencedwith soil fertility for crop production, theresponse from all three groups involved in thestudy was the unstable price of agriculturalproducts (Figure 1). This was confirmed by thefindings of interviews with key informants(hamlets leaders) and fertiliser retailers. The ferti-liser retailers also reported that farmers facedhardship in financing fertiliser inputs since theyobtained them on credit and repaid their debtsafter harvest. One group of farmers related theproblem of low product prices to a surplus of pro-ducts because ‘many people have invested inagriculture’, resulting in increased competition.A newly established orchard area that had juststarted to give yields was cited as an example ofthis. All three groups mentioned that priceinstability had led to an under-investment infertilisers, leading to a decline in yields. However,sugar cane was the only crop specifically men-tioned as receiving less, in fact no, fertiliserinputs due to low prices for the product. Whenquestioned in depth, the farmers also offeredother explanations for the perceived declinein yield of some crops, for example growing

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the same crop repeatedly on the same land (man-gosteen, Garcinia mangostana L.), or changes in theclimate. A suggested solution to counteract theunstable market was the introduction of newcrop varieties and better post-harvest processingtechniques (e.g. canning) in order to bettercompete on the market. The farmers alsoclaimed that the unstable market led to lack ofon-farm labour, as young people preferred towork off-farm in the nearby industrial area,since this provided a more stable income.

Soil acidity and poor soil structure were alsomentioned as problems related to low yields(Figure 1). According to one group of farmers,soil acidity was indicated by yellow precipitatesin ditchwater. A method to counteract soilacidity practised by the farmers was to add pow-dered lime, superphosphate or manure. Poor soilstructure was mentioned as a consequence of soilacidity and could be improved through additionof rice husk ash and by selecting suitable crops. Inone group, the farmers mentioned how they hadstopped growing mango trees (Magniferra indicaL.) since this tree had proved to be sensitive topoor soil structure.

Flooding was a problem mentioned in allgroups and was perceived as being caused by achange in rainfall patterns, which had led to

more rain; both heavy rain during the dryseason and more rain during the rainy season.Discharges from a dam upstream during heavyrains were also thought to contribute to flooding.Because many of the crops grown are sensitiveto flooding, this resulted in lower yields. Asuggested solution to the flooding was to buildhigher dykes, which would require investmentcapacity.

Farmers’ use of fertilisers

When asked what fertilisers they used thefarmers mentioned urea, NPK, superphosphate,ash, pig manure, chicken manure, quail manureand peanut cake. Lime was also used andreferred to as a fertiliser. The ash originatedfrom firewood (wood ash) or rice husks (ricehusk ash) burnt in the kitchen, the potteries inthe area, or the brick factories in the Mekongdelta. Solid pig and chicken manure was alwaysstored before use, and sometimes mixed withash. Liquid pig manure refers to the water fromwashing the urine and faeces from pigsties. Itwas only used to a small extent and was dilutedbefore use. The peanut cake was a residue frompeanut oil production. The most frequentlyused fertiliser (by volume) was wood ash, NPK

Figure 1 The farmers’ perception of problems with soil fertility. The problem flow shown here is a summary ofthree problem flows constructed in three different group meetings with between 7 and 13 farmers in eachgroup and represents as closely as possible the farmers’ presentations. The number in brackets indicateswhether the issue was mentioned in one (1), two (2) or three (3) of the group meetings

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and stored pig manure on the farms where pigswere kept (Table 1).

Criteria used by farmers when selectingfertilisers

When asked on what basis the farmers selectedfertilisers, they mentioned a wide range of cri-teria. To make evaluation easier the researchersgrouped the criteria into three categories: ‘practi-cal’, ‘pest management’ and ‘functional’. ‘Cheap’,‘easy to find’ and ‘easy to use’ were grouped inthe criteria ‘practical’. ‘Kills pests’ and ‘repulsestermites’ belonged to ‘pest management’, while‘promotes fast growth’, ‘promotes root growth’,‘reduces soil acidity’, ‘makes the soil soft’; ‘long-term effect’; and ‘promotes soil fertility’ weregrouped into ‘functional’ criteria (Table 2).Farmers with annual crops tended to consider‘low price’ important, while farmers with peren-nial crops valued ‘long-lasting effect’ more. Yieldwas only mentioned indirectly by criteria such as‘promotes grain filling’, ‘promotes fast growth’,

etc. The need to alleviate deficiency of a specificnutrient was not mentioned as a criterion whenselecting a fertiliser, but several of the criteriarelated to improving the fertility of the soil.

Characteristics of different fertilisersaccording to farmers

Farmers were asked to evaluate each fertiliseraccording to their own list of criteria (Table 2).The resulting scoring matrix (Table 3) gives anoverview of the characteristics the farmersassigned to the fertilisers. Most fertilisers,except quail manure, peanut cake and liquidpig manure, scored high on one or more of the‘practical’ criteria. All of the modern fertilisers,i.e. urea, NPK, diammonium phosphate (DAP)and superphosphate, were considered to beeasily available, which for the traditionalfertilisers was only true for ash from rice husks.Among the modern fertilisers only superphos-phate was considered cheap. Other cheap fertili-sers were rice husk ash and chicken manure.

Table 1 Farmers’ use of different fertilisers

Farmingsystem

A1 (n ¼ 6) APi2 (n ¼ 9) Pe3 (n ¼ 8) PePi4 (n ¼ 8)

Ranking order Fertiliser

1 Wood ash Urea Diammoniumphosphate

Stored pig manure

2 Super phosphate Wood ash NPK Wood ash

3 Rice husk ash/NPK Stored pig manure Wood ash NPK

4 Diammoniumphosphate

Super phosphate/Ricehusk ash

Rice husk ash Urea

5 Stored pig manure Diammonium phosphate/Peanut cake5

Lime Rice husk ash

6 Urea/Stored chickenmanure

NPK Stored pig manure Diammoniumphosphate/Storedchicken manure/Lime

7 Peanut cake5 Lime Stored chickenmanure

Liquid pig manure/Peanut cake5,6

8 Lime Stored chicken manure

9 Stored quail manure Liquid pig manure

The ranking indicates the farmers’ preference for a certain fertiliser expressed as the volume of fertiliser used. Rankingorder 1 indicates the most used fertiliser. The ranking is the result of a scoring procedure where each farmer distributed amaximum score in a list of fertilisers decided by the group. The maximum score was decided by the group.1Farmers with annual crop.2Farmers with annual crop and pig production.3Farmers with perennial crop.4Farmers with perennial crop and pig production.5A residue from peanut oil production.6Was mentioned, but not used by any of the farmers in the group.

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Lime was the only fertiliser that was used for pestmanagement. All fertilisers except urea scoredhigh on one or more of the ‘functional’ criteria.It was noticeable that, except for superphosphate,only the traditional fertilisers scored high on cri-teria related to long-term soil fertility, whereasthe modern fertilisers scored high on criteriamore directly related to crop growth andproduct quality.

When asked which fertilisers were used forspecific crops, the farmers indicated that urea,NPK, DAP and superphosphate could be usedfor any crop. However, urea was not suitablefor old fruit trees since it made the branchesfragile. Superphosphate was given to all cropsat planting, which explains why it was so littleused on farms with perennial crops. All thedifferent kinds of stored animal manure couldbe used for all crops except durian (Durio zibethi-nus Murr.) and jackfruit (Artocarpus heterophyllusLam.) since it had adverse effects on the colourof the pulp, as oppossed to lime which hadgood effects on the colour of the pulp of thesefruits.

It became clear during the interviews that thefarmers indicated fertiliser quality by the terms‘hot’ (nong) and ‘cool’ (mat). ‘Cool’ fertiliserswere considered to be preferable to ‘hot’ fertili-sers. A ‘hot’ fertiliser could ‘burn’ the leaves,but could be ‘cooled’ through dilution withwater. When individual farmers were asked to

rank common fertilisers on a scale from ‘hot’ to‘cool’, ash from firewood and stored pigmanure were indicated to be the ‘coolest’ fertili-sers, while fresh manure was the ‘hottest’ fertili-ser (results not shown). Mineral fertilisers wereapparently difficult to place on the ‘hot’ and‘cool’ scale since different farmers judged themdifferently.

Farmers’ appraisal of information sources

When asked to list the sources of informationavailable on nutrient management, the farmersfound it difficult to separate nutrient manage-ment from other farming practices, so they wereinstead asked to list the sources of informationavailable on farming in general. The farmerslisted both the information sources they usedand the information sources they knew of: experi-ence, self-experimentation, neighbours, tradition,radio/TV, and the extension club in the village,the extension service in the province, advertise-ments and books. Pair-wise rankings wereintended to be used to reveal the most trustedinformation sources but the farmers insteadranked the information sources according touse, arguing that the most trusted informationsources were also the ones they used mostoften (Table 4). In the rankings the farmers alsomerged experience and self-experimentation,

Table 2 Farmers’ assessment of important criteria when selecting fertilisers

Farming system A1 APi2 Pe3 PePi4

Ranking order Criteria

1 Cheap Promotes soil fertility Long term effect Long term effect

2 Promotes grain filling Promotes rootgrowth/Cheap

Promotes soil fertility Promotes soil fertility

3 Reduces soil acidity Reduces soil acidity Promotes good fruit quality Reduces soil acidity

4 Promotes fast growth Promotes fast growth Repulses termites/Cheap Promotes fast growth

5 Kills pest/Easy to find Easy to use Reduces soil acidity Cheap

6 Long term effect Makes the soil soft Easy to use

7 Promotes root growth Kills pest

8 Makes the soil soft Makes the soil soft

9 Easy to use Easy to find

Ranking order 1 indicates the most important criterion. The ranking is the result of a scoring procedure whereby eachfarmer distributed a maximum score in a list of criteria decided by the group. The maximum score was decided by thegroup.1Farmers with annual crop.2Farmers with annual crop and pig production.3Farmers with perennial crop.4Farmers with perennial crop and pig production.

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arguing that to them they were the samething.

The rankings showed that the farmers pre-ferred the information sources that provided themost specific and locally adapted information:neighbours, own experience/experimentationand tradition (Table 4). Information was sharedwith neighbours in coffee shops but farmerswere cautious about sharing information withneighbours who were also considered to be com-petitors, so the shared information could notalways be trusted. Tradition was a more specificinformation source for farmers growing peren-nial crops than for those growing annual crops,which was reflected in the rankings. Althoughthe extension services received a low ranking,the farmers commented that the informationfrom neighbours could have originated from theextension service since at least some of thefarmers attended the extension club and usedinformation presented there for their own experi-ments. Other farmers complained that the exten-sion club promoted composted plant materials,which are laborious to use and not suitable forlocal conditions. Information from radio/TVwas not suitable either since the information pro-vided did not recommend the use of ash, whichshowed that it was not relevant to the conditionsin An Son. The extension service centre also pro-vided unspecific information since the infor-mation brochures available mostly describedcrops that were not grown by the farmers.Overall, the farmers did not really express ademand for more or better information; rather

they requested new crop varieties and betterpost-harvest techniques to improve their compe-titiveness on the market. The fertiliser retailersconfirmed that the farmers were usuallyconfident about their inputs and input levelsas they seldom asked them for fertiliserrecommendations.

Discussion

Despite the earlier reported excessive nutrientinputs (Hedlund et al., 2003), the results of thisstudy clearly indicated that farmers believedthe level of fertiliser input to be too low and theresult of ‘an unstable market’. As one farmerput it: ‘We know how to get maximum yield ifonly the price (of the product) is right’. Oneexplanation for this view may be a prevailingparadigm of input expansion that is common inareas that have recently experienced a ‘greenrevolution’ (Pandey, 1999).

The study further showed that the farmers’concept of fertilisers appeared to deviate fromthe scientific concept of fertilisers as primarilyplant nutrient sources, as the latter function wasnot mentioned as a criterion for fertiliser selec-tion. Instead, the farmers’ concept of fertiliserswas broader and classified as amendments thatwere added to promote good conditions forplant growth, either directly (‘promotes fastgrowth’) or indirectly by improving soil fertility,alleviating soil acidity or reducing pests, which

Table 4 Farmers’ appraisal of different information sources investigated by pairwise ranking in four groups of farmers

Farming system A1 APi2 Pe3 PePi4

Ranking order Information source

1 Experiments Neighbours Neighbours Neighbours

2 Neighbours Radio/TV Tradition Tradition

3 EC5/Tradition/Radio/TV EC5 EC5 Experiments

4 Advertisements6 Tradition Advertisements6 EC5

5 Books6

Ranking order 1 indicates the most often used information source and, according to the farmers, thereby also the highestlevel of confidence in that source.1Farmers with annual crop.2Farmers with annual crop and pig production.3Farmers with perennial crop.4Farmers with perennial crop and pig production.5Extension club in the village/extension service centre in the province.6This source of information was mentioned but received no scores.

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would subsequently lead to increased cropyields.

The farmers’ concept of fertilisers is furtherillustrated by the fact that the fertilisers favouredwere multifunctional, like the traditional fertili-sers. The terms ‘hot’ and ‘cool’ applied to thetraditional fertilisers also indicated more andother functions of a fertiliser than a source ofeasily available plant nutrients.

The absence of plant nutrients in the farmers’concept of fertilisers may have resulted in appar-ently excessive nutrient inputs exceeding nutri-ent outputs by up to 95-fold for N, 150-fold forP and 17-fold for K (Hedlund et al., 2003). Thus,fertilisers may have been added to the soilwithout recognition that nutrients were alsoadded. For example, superphosphate wasadded to overcome the soil acidity and ashwas added to aid the development of soil struc-ture, but the simultaneous addition of P andK was not considered.

Both the farmers’ concepts and the scientificconcepts are based on cumulative and evolvedknowledge. Farmers adopt, adapt and formulatenew ideas and innovations, try them out in differ-ent settings, evaluate and assess results, andmake decisions about their potential value forcontinuously improving their farming methods(van Veldhuizen et al., 1997). An effectiveapproach to rural development for such farmersis to assist them in their development efforts byproviding knowledge that they find difficult todiscover themselves. However, farmers seemedto be reluctant to embrace new external infor-mation, which was illustrated by their preferencefor sources that provided information specific tothe local conditions. Such traditional concepts,based on long-term experience, may serve as agood foundation to understand a stable, unchan-ging environment, but it is also essential thatrapid changes are followed by the transfer of rel-evant external information to the farmers. For asuccessful transfer of information, it is essentialthat new information is provided in a way thatcan be comprehended in terms of traditionalconcepts or formed into new ones suitable forlocal conditions (Sharland, 1997). The highreliance on neighbours as information sourcesrevealed a local information system that has apotential as a means for introducing new infor-mation or concepts to the farmers: some innova-tive farmers took general external informationprovided by the extension service centre, theextension club or the radio and TV, which they

then used for their own experiments, the resultsof which they later shared with their neighbours.These results concur with other findings thatfarmers show a higher level of adoption whennew technology options are introduced by otherfarmers (Duveskog et al., 2003). It also illustratesthe usefulness of farmer-to-farmer extensionand the practice of farmers’ field schools (FFS)(e.g. Minjauw et al., 2003).

Reliability of the findings of the study

All the methods used in this study were indir-ect in that the farmers were not asked directlyabout their perceptions or practices. Instead,their perceptions and practices were revealedindirectly through the PRA/RRA-methods. Therationale for this was to avoid intimidating thefarmers by questioning their values or practices,and to avoid any concern that the farmersmight respond on the basis of their prejudicesregarding the researchers’ expectations. Thedrawback with this method was that it produceda lot of unexpected responses that had to be putinto context, which may in turn have been theproduct of the researchers’ own prejudices.However, the responses in this study werecross-checked with other sources and the con-clusions drawn were a result of ‘immersion’ inthe farmers’ environment; staying in the villageand living with the farmers.

Gender was not taken into consideration in thisstudy, which had the result that the femalefarmers’ strategies for sharing information werenot sufficiently assessed. Even though both menand women participated in the study, thefinding that the farmers share information incoffee shop discussions largely reflects themen’s point of view since coffee shop discussionsimply drinking alcohol, which is mostly a malehabit. Any future attempt to improve the infor-mation flow to the farmers should thereforetake gender issues into consideration.

Conclusions

Introduction of new fertilisers and, as shown inthis study, their ease of access has opened upthe road to excessive nutrient inputs, with poss-ible adverse effects on the environment. Toachieve more efficient nutrient managementusing modern fertilisers, it is essential thatfarmers understand and use the scientific

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concept of plant nutrients. There is a need toassist the farmers in their development effortsby providing knowledge that they find difficultto discover themselves, e.g. the nutrient contentof different fertilisers and the nutrient require-ments of the different crops. The local infor-mation system shows that farmer-to-farmerextension and FFS may be an appropriatefollow-up to develop fertiliser managementsystems with improved nutrient use efficiency.

Acknowledgements

This project was supported by Swedish Inter-national Development Agency (SIDA). Weexpress our gratitude to Prof. David Gibbon forhis valuable comments on this manuscript, andMr Tran van Minh, An Son, for his unlimited hos-pitality. We are also grateful to the People’s Com-mittee of An Son that made it practically possibleto carry out this study; Dr Ngo Van Man and MrNguyen Quang Thieu, Miss Phuong Yen and MrsNga who provided valuable help with the trans-lations; Hanna-Metta Olsson and Charlotta Hultwho helped gather data, and Dr Vo Khac Triwho provided the rainfall data. Mr Nguyen vanKe and Mrs Pham thi Minh Tam provided valu-able help in finding the English and scientificnames of the crops. Dr Tran Kim Tinh and DrJan Eriksson provided valuable help in the classi-fication of the soils.

Correspondence

Any correspondence should be directed toA. Hedlund, SWECO VBB, Gjorwellsgatan 22,PO Box 34044, SE-100 26 Stockholm, Sweden(anna.hedlund@sweco.se).

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