AN V N T ; \. R ES(M A:~ MANA(GEMEJNT:
and Training Support (ARTS) Project,
Burkina Faso, 1990-94
Pirdue University and WinrCk International
A.1ID. Contract # 624-02 70-C-00-001 2-00
and Training Support Project
Purdue University and the
Institut d'Etudes et de Recherches Agricoles (IN.E.R.A)
in collaboration with Winrock International
A.I.D. Contract No. 624-0270-C-00-0012-00
The editors gratefully acknowledge the organizational skills of Mrs. Katy G. Ibrahim and Ms. Wendy Shorter who were responsible for the preparation of this document. Appreciation is also extended to the skilled French and English translators, Jean-Marc Boffa, Sylvie Kauffinann, Jennifer Jakovljevic, and Christian Gautier for their contributions.
This is a technical report of research in progress at the Institut d'Etudes et de Recherches Agricoles (IN.E.R.A). Although the ARTS project has ended, agricultural research in Burkina Faso is just beginning. The work done during the ARTS project will be a starting point, not an end in itself. Results will be further tested and conclusions will continue to be refined.
In this context, the usual summary of project results written by the campus staff and technical assistance team would be inappropriate. Instead this technical report is composed of "working papers" co-authored by the Burkinab6 and American scientists. These are working papers in the sense that they are not final products, but rather documents written to help researchers organize their materials and communicate preliminary results to those colleagues whose comments and criticism are essential elements in refining and polishing scientific communications.
This document is by nature a partial record oif the ARTS project accomplishments. Some activities remain to be completed. Others have yet to be analyzed and written up.
French and English versions of the technical report are being published to facilitate communication. The original language of a working paper is noted in the table of contents. Because of timing and logistical problems authors have not had the chance to proofread the translations of their papers. The version in the original language should be considered the definitive version, if the word "definitive" can be applied to a working paper.
As with all working papers, comments and criticism from readers is welcome. Comments should be addressed to the authors of individual working papers.
A complete summary of project objectives and activities can be found in the administrative report entitled "Integrated Research in AgriculturalProduction and Natural Resource Management: Agricultural Research and Training Support (ARTS) Project, Burkina Faso, 1990-1994, Administrative Report."
Table of Contents
Section I Soil and Water Conservation
Principal Production Constraints and Findings of a Selection of RSP Production Research, 1990-1994 ..........................................1
J. Dickey, E. Sankara, A. Sohoro, and S.J.-B. Taonda***
Survey: Farmer Evaluation of Zal in Donsin, 1993'. ............................17
E. Robins and M.-C. Sorgho
Economic Analysis of Compost Production in Southwestern Burkina Faso............... 29
S. Amadou, M. Bertelsen, and S. Ouedraogo**
Use of Unconventional Products in Animal Health Case: The case of Draft Animals in Burkina Faso. ..........................................37
Evolution of Sedimentation, Surface Micro-Morphology, and Millet Production in Response to Soil Conservation Practices on an Eroded Site at Yilou, Burkina Faso ........ 43 N.F. Kambou, S.J.-B. Taonda, R. Zougmor6, D. Kabor6, and J. Dickey*
Characterization of the Soil-Plant System in Bush Fields in the Tropical North Sudanian Region of Burkina Faso............ ............................. 55
S.J.-B. Taonda, J. Dickey, P. S6dogo, and K. Sanon**
Economics of Rock Bunds, Mulching and Zai in the Northern Central Plateau of Burkina Faso: A Preliminary Perspective....... ............................67
D. Kabor6, F. Kambou, J. Dickey, and J. Lowenberg-DeBoer***
The Value of Research on Indigenous Knowledge: Preliminary Evidence from the Case of Zai in Burkina Faso ................................................ 83
M. Bertelsen and S. Ou6draogo**
The Economics of Rock Bund Construction on Sorghum and Millet Fields in Burkina Faso ....... ........................91
D. Kabor6, M. Bertelsen, and J. Lowenberg-DeBoer***
Section II Cropping Systems
Farmers' Evaluations of On-Farm Tests and the State of Village Natural Resources (Results of the Farmer Opinion Surveys 1990-1994) ................... ... ..... 105
Women's Agricultural Strategies in the Central Plateau, Burkina Faso ................. 121
M.-C. Sorgho and E. Robins***
Performance of Several Sorghum Lines Under Striga hermonthica Infestation: Preliminary Results from Kawara, Burkina Faso .................................131
E. Sankara, J. Dickey, L. Butler, and G. Ejeta**
Analysis of the Production System and Farming of Rice By Women in the South West of Burkina Faso: The Case of Kawara Women in the Como6 ..............135
On-Farm Performance of Forage/Grain Varieties of Sorghum and Cowpea: Agronomic Evaluation by Researchers and Farmers.............................. 145
A. Sohoro, S.J.-B. Taonda, J. Dickey, and E. Robins*
Sorghum Variety-Fertilizer Interactions in the Village of Kamsi ...................... 155
A. Sohoro, S. Ou6draogo, and J. Dickey***
The Riskiness of Alternative Phosphate Sources in Burkina Faso..... ..... ...165
V. Hien, D. Kabor6, S. Youl, and J. Lowenberg-DeBoer***
Upland Rice: An Alternative For Cash Crop Diversification to Stabilize Farm Incomes in Western Burkina Faso.............. ........................... 175
E. Sankara, A. Sidib6, and J. Dickey***
Dynamic Recommendation Domains in Burkina Faso: A Geographic Information System as a Tool for Facilitating the FSR-Extension Connection.................... 183
M. Bertelsen, S. Ouedraogo, J. Dickey, S.J.-B. Taonda, E. Robins, and D. Kabor6***
Section III Integration of Livestock and Crop Production
Supplementary Feeding of Milking Cows with Cottonseed Meal for Improved Dry Season Productivity in Western Burkina Faso ....... ............ ...... 191
A. Lalba and J. Dickey*
Use of Unconventional Products in Animal Health Care: The Case of Draft Animals in Burkina Faso .......................................................201
Dynamics and Management of Animal Traction in Western Burkina Faso: A 1990 Diagnostic Study........................... ................... 207
Section IV Agroforestry
Researching Tree Management Strategies in Thiougou Village, Central Plateau, B urkina Faso ................. ............................................... 225
The Economics of the West African Parklands Agroforestry System: Preliminary Evidence from Two Central Plateau Villages in Burkina Faso .............. 235
M. Bertelsen and D. Kabor6**
Economic Analysis of Some Activities of Women Linked to the Use of Non-Woody Products of Local Forest in the South West of Burkina.......... ......... 251
Establishment and Management of karit6 (Vitellaria paradoxa) Parklands in Sudanian Burkina Faso. ............... .............................. 259
J-M. Boffa, L. Lompo and D.M. Knudson***
Section V Research Extension Issues
Farmer Participation in a New FSR Program in Burkina Faso, West Africa ...... .. 281 E. Robins, W. Fiebig, and S.J.B. Taonda**
Extending Agricultural Innovations in the Multi-Ethnic and Multi-Cultural Societies of Western Burkina Faso............................................ 297
D. Ilboudo and E. Robins***
Collaborative Agricultural Systems Research in Burkina Faso 1992.............. .... 313
E. Robins, P. Sanou, S. Oubdraogo, and D. Ilboudo***
Definition of New Intervention Zones of the R.S.P. Program with Geographical Information Systems. ................. ...................... 317
B. Djaby, M. Bertelsen, and S. Ou6draogo
Section VI Agricultural Policy and Land Tenure Land Tenure and Farm Productivity in Western Burkina Faso......................... 325
The Challenge to Create a Durable Agriculture: The Experience of Burkina Faso ........ 333 S. Ou6draogo*
Section VII Baseline Socio-Economic Studies Farmer Participation in Generating Village Socio-Economic Profiles ................. 341
E. Robins, M. Bertelsen, and D. Kabor6** The Settling of Western Burkina: Future Trends for Village Societies ................. 353
Women's Activities in the Village Research Sites of the RSP Western Zone ............. 371
D. Ilboudo and P. Lingani*
List of Abbreviations and Mor6 Words ................................393
* Original Document in French
** Original Document in English
*** Supplied by author(s) in English and French
SOIL AND WATER CONSERVATION
Principal Production Constraints and Findings of a Selection
of RSP Production Research, 1990-1994
J. Dickey, E. Sankara, A. Sohoro, and S.J.B. Taonda
The approach of RSP during the period of the ARTS Project was similar to RSP's continuing methodology which consists of the following general steps:
- Diagnostic study (problem definition, definition of important demographic economic,
natural, social parameters)
* Identification of potential solutions, including preliminary discussions with farmers, as well
as appropriate development and research personnel
* On-farm technology testing to provide a common base of experience with technology among
farmers and researchers of various disciplines
* Field observation (observations of production, natural resource evolution, farmer opinion,
farm expenditures and income), laboratory analyses (statistical, chemical, physical, etc.), and
evaluation of results. Farmers, and ideally collaborators in development and research, take
part in field evaluation
* Restitution of results to collaborators, especially to farmers, and refinement of results by
collaborators, especially farmers.
.This process is necessarily iterative, but to the extent possible, each cycle should produce something usable by farmers, development, and/or research. The formats for communication with these groups are informal and formal. Formal means include field days, meetings, reports, technical bulletins, and scholarly presentations, articles, theses, and dissertations. Informal means are visits among small groups of individuals.
The activities of the ARTS Project were limited mostly to the Central and Western Zones of RSP, which contain 8-village sites (Figure 1). These sites encompassed a wide variety of socioeconomic and biophysical production conditions, some of which are summarized in Table 1.
zones Le Zone
* Major City East (9 P SiteWes
Table 1: RSP Village Sites, Central and Western Zones Zone Village! Animal Principal Crops Level of NR Dominant
Annual Traction Degradation Migratory
(mm) ____ ___'_Central Donsin Absent Sorghum, millet Extreme Old and recent
Central Kamsi Little Sorghum, millet Advanced Recent
Central Thiougou Dominant Sorghum, millet Moderate to Recent
723 advanced emigration
Western Yasso Dominant Sorghum, maize, -Moderate to Old and recent
S802 "cotton advanced immigration
Western, Kayao Dominant Sorghum, maize, Moderate to Recent
819 cotton advanced immigration
Central Tiano Dominant Sorghum, maize Moderate Recent
Western Kawara Little, but Maize, sorghum, Slight' 'Old immigration
1010 increasing rice
Western Dimolo, Little, but Maize, sorghum, Slight Slight, recent
1015 'increasing yam .. .. immigration
apost-969. 1 For West African sites, rainfall means including post-1969 data are considered a better indicator of current rainfall expectations than means including pre-1970 data. This is because a relatively rainy period of what appears to be a long-term climate cycle came to an end in about 1969. Post-1969 means for RSP villages are from 150 to 200 mm less than means for pre-1970 data.
A number of the papers contained in this collection are the results of work on individual research themes that made up a coordinated, evolving research program. Each work had a place in the above research process, and many were interrelated. This paper is not an exhaustive listing of all research activities. Rather, it ties a selection of activities to the principal constraints they were meant to address. The objective is to share some of the overall logic of the production research activities, and thereby to provide a general context for the various individual studies reported in other papers.
Principal Constraints:Major constraints to sustainable, secure, and productive management of natural, other capital, and labor resources in Burkina Faso can be divided into primary (fundamental), secondary (derived from fundamental constraints), and tertiary (derived from secondary constraints) groups.
1. Shortage of uncultivated land for clearing and cultivation, pasturage, or gathering (of wood,
pharmacopoeia, mulching materials, or other forest products). This is generally due to
demographic pressure on the land resource.
2. Erratic rainfall, especially early- and late-season drought periods, as wellas occasional and
very damaging mid-season droughts.
3. Pest and disease pressure on production (e.g. Striga spp.,maize streak virus, downy mildew,
numerous cowpea insect pests).
4. Insufficient access to markets (e.g. maize sold inYasso at 2500 CFA/100 kg, January, 1994)
and erratic, often low pricing (e.g. the 1993 cotton crisis).
5. Storage pests and rots, especially for their effect on seed and setts.
Traditional, low-input, rotational bush fallow farming systems require large land areas to function productively, since a large percentage of the land must be in fallow at any one time. Demographic pressure is such that this is no longer possible in many areas. Rainfall quantity and distribution are rarely ideal and often result in significant stress on plants and animals in the production system. Pests and diseases, especially when crop vigor is reduced by other stresses, can limit production and destroy planting material. These are cited as primary constraints because they exist in the presence or absence of other constraints, although they do give rise to other (secondary) constraints.
6. Insufficient village political organization to solve resource-use problems (e.g. insecurity of
usufruct landholders, chronic cultivator-pastoralist conflicts).
7. The degraded state of land (including soil and vegetation) resources. For the soil this
includes erosion, crusting, reduced water holding capacity and organic matter contents, as
well as chemical constraints to fertility (largely shortages of N and P) and localized acidity.
Wild plant and weed communities have become less diverse, more dominated by plants
selectively preserved by farmers (e.g. Hibiscus sabdarifa or da, Butyrospermum paradoxum
or karit6), relatively unpalatable forage and browse, and weed populations capable of
surviving continuous cropping and frequent cultivation (e.g. Digitaria horizontalis, Striga
Primary constraints on land require that this resource be managed skillfully by village communities. Traditional land tenure systems provide the community with a rich assortment of tools. However, these systems are often understandably in the process of adapting to changing demographic conditions (population density, ethnic makeup, and families' economic objectives), and a deteriorating resource base. During this period of adaptation, when production systems must be transformed in profitable steps, substantial physical and biological degradation of the land base can occur. Organization for land management (constraint.6) and land degradation (constraint 7), therefore, are secondary constraints by virtue of their dependence on constraints (1) and (2).
8. Shortage of biomass (animal wastes and vegetative matter) with which to nourish people,
crops, livestock and wildlife.
9. Scarcity of labor and animal traction in certain regions, making cultivation and materials
transport (of organic fertilizer, mulch, and stones, for example) for land management very
10. Ignorance of resource management possibilities and probable results. 11. Access to capital (partially resolved for cotton producers, who use cotton credit to purchase
fertilizer used on a number of other, notably grain crops).
12. Poor animal health due to insufficient nutrition and veterinary care.
Degradation of the land resource and failure to address this degradation by changing village land management (secondary constraints 6 and 7) requires that farmers seeking sustained production invest labor and capital in land maintenance (fertility, soil and water conservation), pest control, and animal feeding (on distant pastures or cut forage), however, these efforts are often insufficient. These unmet needs give rise to the tertiary constraints listed above.
II. RESEARCH ACTIVITIES
Thematically, the activities can be broken down into the following categories:
Crops and cropping systems
1 Varietal evaluation, including analysis of yield stability
2. Disease and pest management
3. Evaluation of agricultural machinery and its use
4. Training in methods of seed/sett production and storage
5. Evaluation of crops or cropping systems
6. Improved feed production, livestock feeding, and animal health
Environmental monitoring, conservation, and regeneration
7. Soil fertility, including use of mineral fertilizers, fabrication and use of organic fertilizers,
and definition of fertility requirements of varieties
8. Land conservation and reclamation
9. Characterization of land degradation and variability 10. Environmental monitoring
Findings: Crops and Cropping Systems. Farmers' needs and measures they are willing and able to take to resolve them vary greatly across Burkina Faso. While much of this variability is due to the nature of the individual farmer, some community characteristics help one to understand and organize thinking about farmers and their behavior. The environmental conditions and the importance of cotton in the production unit strongly influence the way people farm in Burkina. This, in turn, has a large impact on the relevance of a given
technology to farmers. The influence of these factors on farmers' use of inputs and animal traction for land preparation and weeding are described below. Clearly, cropping environments that are untilled, unfertilized and weedy will welcome different kinds of innovations than fields that are tilled, fertilized, and weeded on time. This makes it critical to understand these patterns of land management before discussing research results for specific technologies.
Prolonged and substantial public investment in cotton production (extension of information on improved practices, credit for equipment purchase and production costs, input availability, and organized marketing) has borne fruit. Farming practices in cotton production areas are in general strikingly different from practices outside these areas.
There are areas with favorable environmental conditions for crop production, which for various reasons do not currently produce much cotton." Naturally, these areas benefit much less from investments made to encourage cotton production.
Farmers in the Central Zone, generally not cotton producers, lack access to credit and run a greater risk of crop failure. This is especially so in the dryer northern areas, where rainfall is scarce and relatively erratic in distribution. Farmers therefore favor a strategy that minimizes capital inputs, thus limiting the capital put at risk. Five examples along this transect, taken in RSP villages, follow. Refer to Table 1 for additional information about these villages.
At Kayao and Yasso a high proportion of farmers have and use animal traction, (for land
preparation, weeding, and transportation), cotton is widely produced, and chemical fertilizers are habitually applied to field crops (not only to cotton, but also to cereals, especially maize).
The combination these practices with higher, less variable rainfall than in much of the rest of
Burkina Faso provides field conditions with relatively high yield potential and low risk of
* At Tiano there is relatively little cotton, yet farmers have a rather entrepreneurial approach
to farming, (many are recent migrants). Many farmers have animal traction, and are prepared
to plow and apply chemical fertilizer to achieve good maize yields on large areas.
- At Kawara and Dimolo, little cotton is produced, and the use of animal traction,
mechanization, and inputs is much less prominent than at Kayao and Yasso. Dimolo youths
are frequently absent, gone to Cote d'Ivoire to find wage labor jobs. Farming of rice on
hydromorphic soils is a major activity at Kawara.
At Thiougou, many farmers have animal traction and plow, and organic fertilizer is produced
(some with Burkina phosphate rock phosphate -,added) and used intensively in village
fields. Practically no fertilizer of any kind is used in bush fields. Maize in large fields is
considered too risky. Farmers are sometimes willing to purchase pesticide for cowpea
At Donsin, animal traction is very rare, farmers recently began very labor-intensive use of
manure and compost in zai in 1993, and practically no mineral fertilizer or pesticide is
purchased. Cash is scarce and needed to pay for food during the hungry season (July,
August). Farmers are clear in their priorities; many will not spend money on pesticide or
* Kamsi is somewhat particular due to the large amount of dependency on income from
emmigrants, which changes farmer motivation.
The use of inputs by farmers in the cotton-production region means that new varieties find themselves in much the "improved" (relatively low-stress) conditions that the breeders who developed them anticipated. As a result, varietal introduction is relatively easy and effective. That is, a new variety has a reasonable chance to out-yield the local variety in a farmer's field, so if its culinary quality is satisfactory, it runs a good chance of some adoption and of making a positive impact on production. Testing is straightforward: put the variety in the field under conditions stipulated in the breeder's technical bulletin, because the breeder knows what the variety needs to perform, and the farmer frequently can approximate these conditions.
On the other end of the spectrum, the strategy of farmers at Donsin (on all fields) and at Thiougou (in the bush), however, is in direct conflict with the dominant milieu of varietal selection and with management stipulations in technical bulletins associated with improved varieties. These bulletins are conceived to allow these varieties, given adequate rainfall, to yield well, (or to realize their potential). Low to moderate doses of chemical or organic fertilizer are generally recommended, and in the case of cowpea, so is treatment with insecticide. When planning varietal tests in cultural environments that do not match the bulletins' recommendations, the question becomes who to please, the breeder or the farmer?
The research approach in the Central Zone was therefore two-tiered, with new varieties introduced under at least two fertility regimes, to get an idea of how varieties would do under farmers' and "improved farmer-managed" conditions, and therefore of their stability across the real spectrum of fertility conditions. The results for sorghum, millet, and cowpea were surprising: local varieties frequently out yielded improved varieties at both ends of the fertility spectrum, exceptions being the millet IRAT P8 (virtually identical to the local), millet IKMP-3 (which yielded slightly better than the local without fertilizer), and the cowpea local Donsin (which did not respond to fertility as well as improved varieties).
Improved peanuts yielded well and were similar to locals across the fertility spectrum, except at Thiougou, where the local was slightly superior.
Several good, disease resistant maize varieties had been produced by INERA and were in theory already passed to extension, however these varieties were relatively unknown in all RSP villages. Introduction of these maize varieties was of interest to RSP for the following reasons:
* It benefited cooperating farmers.
* It responded to a need for new alternatives in the face of difficulties in the cotton sector.
* It provided a common base of experience in food crop production for farmers and the RSP
teams. (All aspects of maize production and the adoption ofnew technology were studied by
the various disciplines, not just yield performance.)
Productive working relationships and dialogue between cooperating farmers were developed
around this and other production activities.
At Tiano, maize varieties SR22 and DMR.W each produced about 3 Mg/ha (at recommended fertilization rates), out yielding local maize by about 20%. The variety SR22 was so productive in Kayao, Yasso, and Kawara that it was rapidly adopted. The early maize varieties KPB and KPJ were tested and adopted by some, especially in Dimolo, as crops to provide some early relief from the hungry season. Tested hybrid maize did not perform well, and in retrospect probably had little place in on-farm tests.
Another promising innovation is the introduction of upland rice cultivation, based on the availability of early varieties adapted to upland conditions, (FKR-5 and FKR-33). Yields averaged over 2 Mg paddy rice/ha, and maximum yields were upwards of 5.5 Mg/ha. Yield stability of FKR-33 was superior, while given adequate rainfall, FKR-5 had higher yield potential. In general, the crop is sensitive to dry spells of over 10 days. The preceding crop is important, with preference in the order rice < upland cereals < cotton < garden crops. Hand planting and weeding consume an enormous amount of labor and are the major constraints to increased area in upland rice. Mechanized and chemical weeding were examined in 1993, each showing some promise. The INERA Water, Soil, Irrigation, and Agricultural Mechanization program (ESFIMA) worked on tools for mechanized planting at close spacing during 1993, and RSP will test these tools in 1994. RSP has done some work on hand-planting rice at wider spacing, also with some success. Burkina imports a great deal of rice. If prices stay sufficiently high, there is tremendous productive potential for rice in Burkina Faso.
Untimely weeding is a major upland cereal production constraint in the Western Zone. As for rice, herbicides are on the market and used by some farmers. Without prejudging the environmental or production advantages of chemical weed control, tests in maize (on-station and on-farm) began in 1993. Controlwas frequently achieved, but the economic benefit is less clear than for rice.
Sorghum, on the other hand, suffers greatly from Striga infestation, especially on continuously cultivated land. Striga is cited by farmers in Yasso and Kawara among their principal production constraints, and as a principal indicator of land degradation. Where land cannot be left fallow, rotation, resistant varieties, and chemical control are options. Six resistant lines were tested in an infested sorghum field at Yasso in 1993. All lines showed significant resistance relative to the local check. Taken together, the six lines had 13% of the Striga infestation level of the local check, and produced 242% of its grain yield. Spraying with 2,4-D was also effective, and relatively inexpensive due to the low cost of this herbicide.
Mildew-attacks millet in much of Burkina Faso, with the yield reduction depending on severity. The seed treatment Apron Plus, (100 g metalaxyl, 60 g carboxine, and 340 g furathiocarbe, all per kg of powder), provides protection from mildew at about 2000 CFA/ha, equivalent to about 25 kg millet/ha. RSP has participated in widespread testing of the product in farmers' fields and developed a technical bulletin for the use of Apron Plus aa well as another bulletin to help estimate the potential economic benefit of using Apron Plus in a given field. Impact appears to depend on the region, particularly on the native level of mildew infestation.
As for use of insecticide on cowpeas, the approach up to 1994 was to treat as needed, and to experiment with cereal intercropping as a means of reducing the absolute need for insecticides. Given the response of many farmers (indicating unwillingness to purchase insecticide), a test oriented toward reducing the number of insecticide treatments is planned for 1994. The test will include some of the more resistant cowpea materials that are currently available. Among monitored farmers, few at Donsin treat their cowpeas, yet they manage to get acceptable harvests, even with improved materials, which they generally consider more susceptible to insect attack. This has not been the case at Thiougou, where insect attack is much more severe. Farmer interest in cowpea as a source of food, cash, and fodder (roughly in that order) is strong.
Production quality and quantity are very important issues for grain/forage varieties of cowpea (7/180-4-5) and sorghum (ICSV-1049). In Donsin, where grain production for human consumption is the overwhelming preoccupation, the lower yields (relative to KVX395-4-4 and local), the recommended forage harvest date (after one pod picking), and propensity for shattering limited interest in 7/180-4-5. On the other hand, Thiougou farmers, while noting that the grain production is somewhat low, appreciated the forage qutiality, and seemed willing to sacrifice second and third pod pickings to get quality forage. The need to nourish draft animals motivated farmers most strongly to produce forage.
The caudatum heritage of the sorghum ICSV-1049 renders it particularly sensitive to head rots, and makes the grain difficult to process into flour. It also appears to be sensitive to late-season drought. At least in the south (Thiougou), delayed planting (as recommended) can largely resolve the problem of head rot, if the end of the rains is timely. As with cowpea, the feed value of the stalk, (which is considerable animals prefer it and will destroy fields to get it), is more appreciated in the south, where animal traction is more common and where food production is more assured.
This leaves a large hole in what RSP has to offer to farmers in the way of cereal grains. Through 1993, no sorghum or millet has competed favorably with local varieties for a substantial spot in the farming system. In 1994, the sorghum varieties Sariaso-9 and Sariaso-10 will be tested in all sites. Sariaso-9 is an improved local selected at Saria (about 710 mm/year average annual rainfall since 1970), and Sariaso-10 is another improved caudatum. Only Sariaso-9 will be put under farmers' management. In the south, planting date trials will be run jointly with the Sorghum, Millet and Maize Program (SOMIMA) to refine this aspect of management.
To further respond to severe limitations to pasturage and corresponding farmer interest in forage production (at Yasso and Kayao), several alternatives for feeding are being explored:
* Production ofAndropogon guayanus in vegetated bands in fields
* Improvement of feed value of crop residues by grinding and mixing with urea
* Supplement with cottonseed cake, a byproduct of cotton processing
* Production of forage crops, like dolic and sudan grass (Sorgho sudanense)
Benefits from these feeding systems can include:
* Improvements in animal health and reductions in mortality
- Increased weight gains (recorded for milking cows and calves) and milk production
* Strengthening of draft animals before the cropping season
* Concentration of animal wastes and association with compost pits or bins
So far, farmer interest in these alternatives is running high. The economic benefits of supplementary feeding seem to be high when meat prices are high (as they have been since the CFA devaluation in January 1994), and milk prices are good (in zones like Kayao and Yasso, where milk consumers outnumber milk producers).
A general problem for all crops is production and storage of high-quality planting materials. There are two cases in which high levels of farmer and RSP interest have combined to help solve this problem. When SR22 trials were at first successful in 1991, large, seed-production fields were established during 1992, and this constituted much of the seed supply for the widespread planting of this variety in 1993. Likewise, several kg of sudan grass was successfully multiplied at Yasso in 1993 for more widespread production of seed and forage in 1994.
Seed production and post-harvest storage is also the focus of several other 1994 activities. The problem of storage, especially seed storage, is most pronounced for cowpea. It is sensitive to a number of storage pests (notably bruchids). Seed production and storage is also a hurdle when farmers wish to retain a new variety in their cropping system: a sustainable local seed stock must be established. For this reason, production and storage of quality seed is the major theme of the monitoring of farmers' use of improved varieties in 1994 and in other, specific, seedproduction activities for sudan grass, cowpea, and dolic. Siting and maintenance of fields will be monitored jointly, and training in effective storage techniques will take place at harvest time. Likewise, training in and farmer-testing of sett multiplication for yam began this year at Tiano. This activity will be followed up by activities in yam production and storage.
Yams for market also suffer from storage problems. Large yams are preferred for the premium they bring in the market, but they store poorly. One of the varieties involved in the yam activities is Florido, which is smaller in size and lends itself to planting in ridges instead of the traditional mounds. It could provide a product to store and sell later in the year, when large yams are off of the market and small yams bring a good price. Also, when produced in ridges, it can produce roughly double the yield of the traditional variety in mounds. Setts multiplied for both local and Florido during 1994 will be planted in these two systems for comparison in 1995. Marketing will also be monitored.
The above work was oriented toward understanding and improvement of crops and cropping systems. RSP also devoted much of its research effort to the broader, natural-resources context of crop production. Among other things, this includes land conservation and reclamation.
III. FINDINGS: ENVIRONMENTAL MONITORING, CONSERVATION, AND
The RSP Geographer produced maps of natural resource distribution and use for each village, based on aerial photographs and field investigations. These maps and the associated knowledge base have been invaluable tools for orienting subsequent work in sustainable resource management and production. Many of the impressions of land use in this report are derived, at least in part, fromthose mapping efforts.
One of the greatest challenges facing Burkina Faso is the identification and implementation of sustainable land use in the most productive regions. These same regions also receive many immigrants.: As areas of bush and old fallow are grazed, logged, or cleared and farmed, their capacity to produce fuel, feed, food, fiber, and pharmacopoeia is often degraded, sometimes irreversibly. If this land resource is lost, this largely agricultural country risks becoming one of the worlds' "basket cases". For this reason, several research activities have focused on various aspects of land degradation, conservation, and reclamation.
As with other cultural practices, soil management problems and the measures farmers are willing to take to solve them vary greatly by region. Understanding of the pattern of this variation is critical if one is to interpret farmers' reactions. Major driving forces of this variation are population density, rate and history of migration, and climate. A sample transect of these factors and of land management across Burkina, stopping in RSP villages (Table -1) would be:
*Dimolo (1015 mm rainfall/year mean from 1970 to 1993), where bush land is available for pasture or for clearing of new fields, and the rate of immigration is relatively low. Soilrelated problems are predominantly fertility, and the main action to resolve them is to fallow
land. Animal traction exists but does not predominate, and is used mainly for plowing.
Kayao and Tiano (819 and 848 mm rainfall/year, respectively), where the rate of
immigration is very high, and pasture is becoming scarce with the clearing of more land for
cultivation. Immigrants and natives alike are motivated to cultivate extensively because
cultivation secures land for future use. Animal traction is predominant and is used for
plowing and weeding. For some farmers, soil fertility problems are increasingly addressed
with chemical fertilizers purchased with credit for cotton production, and compost production
Thiougou (723 mm rainfall/year) has some neighborhoods that border the forest. Immigrants have recently settled this land. Land management in these areas is similar to that of Tiano
and Kayao, except for the absence of cotton. Otherwise, Thiougou and Yasso (802 mm/year
rainfall for Yasso) received large, early (30-80 years ago) waves of migration. Migration has'
now slowed due to crowding. In most areas of these villages, very little bush remains to be cleared, and fallow periods on cleared land have become increasingly rare. Animal traction
is widely used for plowing and weeding, and low fertility and Striga hernonthica (a parasitic
weed symptomatic ofcontinuous cereal cultivation) have become major production
constraints. Credit for cotton production has provided a means for chemical fertilizer purchase in Yasso, but there is increasing interest in compost production as an alternative and/or complement. Compost production is widespread in Thiougou, but does not suffice for fertilization of bush fields. Rock bunds were constructed on Thiougou village fields about 10 years ago. With the land shortage and a stabilizing population, farmers in both villages are increasingly prepared to consider land conservation measures, with strong preference for
measures requiring a low capital and labor demand.
Donsin (647 mm rainfall/year) has a relatively stable farming population and practically no
land available for clearing for new settlement. Pasturage is extremely limiting, Striga infestation is widespread, large areas of village land have become so degraded as to be
completely denuded and abandoned, and crop production and the food supply are insecure.
Farmers are highly motivated to stem what they consider an environmental/economic crisis.
On remaining arable land, farmers increasingly use traditional soil and water conservation
measures to improve current and future production (grass mulching, leaving strips of native
vegetation on clearing, laying down of branches roughly on the contour or in gullies to
reduce water erosion). Two years ago, the non-governmental organization Foster Parents'
Plan began to support rock bund construction, (training in contour identification, free
transport of rocks from quarries to fields) and assisted natural regeneration of Piliostygma
spp. This precipitated the sudden and widespread installation of rock bunds on much of the cultivated land. RSP initiatives in soil and water conservation have been rapidly adopted by
most of the village, as will be discussed later. Animal traction is practically absent, and
although fertility constrains production, cash scarcity and high risk of crop failure result in
very little mineral fertilizer purchase. Composting was introduced by RSP, and some farmers
have adopted it.
The character of land and weather dictates management possibilities and, to some extent, their relative costs and benefits. African landscapes encompass extreme variability in productivity and vegetation. High levels of short-range (over distances of several meters) soil variability, for example, are well-documented in West Africa, and pose special management problems. Several of RSP's research projects were aimed at land characterization. These projects included soil/landscape/vegetation mapping, soil sampling and description on short transects to answer specific questions, woody plant community inventory, and detailed evaluation of the process of land degradation under cultivation. The longer-range objective of each study was to provide basic knowledge for the development of sustainable systems of land management.
The large-scale mapping efforts will not be discussed at length. Soil or soil/landscape maps of Kamsi and Thiougou villages were prepared, largely to meet the requirements of two dissertation studies. A vegetation mapping effort was begun at Donsin by the agroforesters. At each site, the soil mapping information contributed heavily to the planning of research. In Thiougou, in particular, it permitted the researcher to control for soil type in a very exacting study of land degradation.
In the context of another dissertation on the socioeconomic role of trees in parklands, woody plant communities maintained by farmers in their croplands were characterized. This
demonstrated the variability of farmer woody-plant management strategies, the importance of variables such as the presence of animal traction in farmer decision making, the predominance of shea nut trees in cleared and uncleared land, and that the pattern of woody plant evolution with timeunder cultivation is not a simple rapid reduction in woody plant numbers and species richness.
Two small studies of soil variability were undertaken. Sampling across a transect heading upslope from a rock bund resulted in a detailed description of erosion, sedimentation, and revegetation across this zone. In a second study; soil samples were taken late in the cropping season across transects of evident soil variability. Corresponding harvest observation plots permitted the correlation of soil and crop results in a village field, in a bush field under prolonged, continuous cultivation, and in a newly-cleared field. Fieldwork for these two studies was informally organized as on-the-job training in micro-profile desciptionand in diagnostic soil sampling in farmers' fields, respectively. Each study required about 1 day of field time. This sort of activity could be used far more frequently to fill data gaps with at least some provisional information, and to create educational fieldwork opportunities with various resource people. The economists made effective use of rapid techniques to respond to specific, welldefined questions (e.g. estimation of opportunity costs of capital, estimation of partial budgets for soil, conservation practices).
In the regions of immigration and little chemical fertilizer use, intensivelymanaged village fields (plowed and receiving substantial organic fertilization)-produce well year after year, even after many years of continuous cultivation. Bush fields, on the other hand, are mined of their fertility and abandoned. Reduced land availability has resulted in reduction or elimination of fallow periods in the rotation, so that fallow no longer achieves the needed regeneration of fertility in bush fields. The nature of land degradation during the years after clearing was studied in great detail. Changes in crop production as well as soil chemical and physical characteristics were monitored and described. Nitrogen immobilization and/or alelopathy limited sorghum yield in the first season after clearing. Thereafter, production decayed exponentially from a maximum during the second year after clearing. The same practices that allow sustainable production in the village (protection with rock bunds, application of 2.5 Mg manure/ha) succeeded in bringing the oldest bush field back from 13 to 74% of the productivity level of newly cleared land.
Several other activities were focused on joint evaluation of soil'and water conservation (SWC) practices with farmers. In Tiano and Kayao, where farmers have little time for these practices, but nevertheless sense a need for a fertility maintenance program, composting activities have begun. In Thiougou and Yasso, where farmers will consider some intensified efforts to conserve land and water, soil conservation, activities are beginning. In spite of the history of rock bunds at Thiougou in village fields, the labor and transportation constraints to their installation makes less demanding technologies (such as vegetated strips) more attractive for the more extensive bush. Land tenure can figure even more importantly in the choice of an SWC technology. In regions such as these, most farmers are on loaned land, and therefore lack the necessary land tenure security, and often the right to install in durable SWC technologies (i.e. rocks, trees). Furthermore, cultivation of land by an immigrant (usufructuary) can augment his
chance of borrowing that land the next year. For the autochthonous farmer, it helps to morally justify a future refusal to loan the land. This motivates both, therefore, to cultivate a lot of land to retain the option of future cultivation. This works against intensive investment in maintenance of a given field. This pattern is most noticeable where the rate of immigration is currently rapid and farmers are therefore scrambling for land.
Donsin has had little recent immigration and therefore land tenure is rather secure for most residents, which helps explain their rapid and enthusiastic adoption of rock bunds when Foster Parents' Plan began to support their installation. Along with the intensive traditional methods of SWC (e.g. grass mulching) that are widely used at Donsin, this suggests a very different situation from Yasso and Thiougou. Farmer opinion surveys and field observations indicated that the problems of food insecurity are substantial and also motivated investment in SWC. Difficulties during stand establishment and with mid- and late-season droughts have all plagued Donsin during RSP's time there and before. Farmers have begun to act.
Indeed, farmer response to the introduction of za'i (manure-filled planting holes), another laborintensive SWC technology, proves this. After a field trip of RSP researchers and Donsin farmer representatives to a zone where zai are used, zai was tested in several farmers' fields alone and in combination with grass mulching, and compared to grass mulching and planting bare ground. In the year of introduction of zai at Donsin, 70% of the production units experimented with them, experiencing variable, but generally very positive results. Fully 80% of production units plan to plant into zai in 1994. The technology is adapted to farmer labor constraints, since most or all of the additional demand is during the off-season, when labor is available. The ability of zai to reduce risk of drought stress by capturing and holding water around a healthy plant reduces farmers' risk, especially during stand establishment. Time for re-sowing is reduced, which increases labor time available for weeding. Due to more timely establishment and perhaps to reduced stress from drought, nutrient deficiency, and weed competition, crop yields are doubled, or tripled when grass mulching is included.
With the rapid adoption of this technology, the major limiting factor for many farmers, especially those with few livestock, will become organic fertilizer. While composting is being practiced by a number of households, its potential to increase organic fertilizer volume in the village has yet to be realized. The scarcity of feed and pasture complicate manure recovery schemes. To increase manure recovery, some producers are beginning to stable animals during the night and constrain daytime grazing to defined areas, from which the manure is collected. Manure is being traded and purchased at Donsin. This ensemble of considerations could motivate forage production by reclamation of rangeland or by forage field-crop production.
A significant proportion of Donsin's land area is highly degraded, producing practically no vegetation (zi-pel6). Although some of these lands were once among the most fertile at Donsin, they are generally considered by farmers to be lost for productive uses. A thematic trial by ESFIMA and field experience of farmers and NGO's in Yatenga and Bam provinces demonstrated that the combination of rock bunds with zai with or without mulch would reclaim such land for cereal production. After reclamation, clearly other land uses (pasture, forestry) could be imagined, however cereal production remains a strong motivator of hungry, rural
families to reclaim land. These results were applied to a zi-pel6 at Donsin, where mulch, za'i, and za' with mulch treatments produced 430, 1060, and 2290 kg of sorghum grain/ha, respectively. Average grain yields in farmers' fields this year was in the neighborhood of 400 kg/ha. As with zai in farmers' fields, these methods of land reclamation are experiencing some adoption on other zi-pel6. The progress of several farmers who have reclaimed substantial areas for cereal production will be monitored in 1994.
Cereal production, or something with a similar payoff, may be needed to pay for the laborintensive practices of zai, rock bunds, and grass mulching. However, more productive pasture may be .sufficient to motivate investment in less expensive reclamation technologies, like small earth bunds in the form of half-moons. One farmer has planned to collaborate with RSP in the evaluation of half-moons for pasture reclamation. The idea is that the bunds slow runoff and favor greater infiltration on eroded, slowly-permeable, shrink-swell clay soils. The wetted soil swells, then dries and shrinks, leaving a somewhat roughened, cracked land surface. Infiltration from the next storm is greatly increased. The greater volume of water stored in the soil supports more vegetation, and the pasture begins to improve.
By any measure, Donsin has demonstrated extraordinary dynamism in the rapid evolution of natural resources management in the village. Likewise, the rapid and widespread adoption of SR22 in maize-production zones signals that an important production constraint was identified and addressed by RSP in the south and west. The enthusiasm for forage (dolic and sudan grass) production and upland rice are producing very successful results. If RSP were a development agency working in these few village sites, this would be enough to claim success.
However, RSP's job is to support development institutions so that they may increase their impact in a much greater number of villages. Therefore, RSP must now describe what has happened in each of these instances in such a way that development institutions can identify similar situations and replicate these successes on a larger scale.
Survey: Farmer Evaluation of Zai in
E. Robins and M.C. Sorgho
"Zal'' is a technology indigenous to Burkina and used in Yatenga on the Central Plateau to reclaim exhausted soils for cultivation. It involves digging a hole 20 cm wide and 15 cm deep. This is then filled with manure and seeds are planted in it. This "zal" creates a moist environment for the plants, which favors germination, growth and crop yield.
In the Namentenga (also in the Central Plateau), where soil degradation resembles what used to be the case in Yatenga, "za has been recently introduced.
The Farming Systems Research Program (RSP) values the experience acquired by the Yatenga farmers, and sees its pertinence for Namentenga. Therefore, to facilitate teaching Namentenga farmers how to fight soil degradation, a "farmer to farmer" visit was organized by the RSP in May, 1993. A group of farmers from Donsin, which is one of the RSP research sites in Namentenga, traveled to Ouahigouya, in Yatenga, to observe water and soil conservation techniques.
Zai was one of the technologies observed during this visit. Donsin farmers were already aware of the existence of this technology. One farmer from the neighboring village of Bonam had tried it the previous year. The latter's highly positive experience encouraged the Donsin farmers to follow his example and try it for themselves. After their visit to Yatenga, these farmers therefore undertook the extension of zai technology to their own village. The number of farmers volunteering to try zal was phenomenal more than 70% of villagers tried it in 1993.
The RSP, together with its collaborating program, ESFIMA, were part of this effort.. They collected data from 6 farmers testing zal. Researchers also demonstrated zai on "zi-p&l6" (i.e. exhausted,- infertile land which no longer produces anything). The results of this are reported elsewhere (the agronomic report by the RSP center team, 1993).
In order to assess the results of the zali trial in the village, the RSP chose a random sample among the farmers surveyed. This report presents the results of this study, which aimed to improve our knowledge of the agricultural impact of zai methods, based on field trials and evaluations made by the farmers themselves.
A stratified and random sub-sample was taken from a sample group of farms, itself chosen randomly for another research purpose (i.e. the socio-economic profiles of village farms). This enabled us to see whether the variation in the farmers' experiences could be attributed, among 17
other things, to their socio-economic status. The sub-sample comprised 37 farmers, who were divided into 4 categories. Another 5 farmers, none of whom had been in the original sample, and who were therefore unclassified, also tested zai methods, following protocol previously established by RSP. These 5 are also included in the sample for this study. The distribution of the sample group is described in Table 1. The 42 (out of 186) farmers studied represented 23% of the village farms.
Table 1. Farmers surveyed on the performance of Zai Producers 1 st 2nd 3rd 4th not Total
Category Category Category Category classified
:group 7 7 7 16 5 42
sample 17 17 17 38 11 100
% of the
village 12 12 24 52 7 100
A questionnaire was compiled and tested. The questions, often non directive (or "open") focused on two main themes:
1. The evaluation of zai used in the previous trials; and
2. the intentions of the farmers concerning the reuse of zai the following year.
The replies were coded, recorded and analyzed with the help of Quattro-Pro software.
III. RESULTS: EVALUATION OF ZAI
The Trial and the Yield. 71% of the villagers tried zai. The majority of them reported a positive impact on crop yield. This is consistent with results from agronomic tests. Refer to Figures 1 and 2.
Zai Test in Donisin 1993 Percent of Villagers Trying Zai
lit Tried (28.6%)
Fg Tried (71.4%)
Yield of the Zai Parcel
in comparison to the control
The yield of zai parcels (zaI alone) was two thirds better than that of the control area ( i.e. the plot with neither za'I nor mulch) according to farmers' estimates. (For example: 10 baskets, as opposed to 6 baskets for the same surface area). Some farmers reported an increase of up to three times the yield on the za plot.
The majority of farmers say that the greatest differences in yield (when comparing plots with and without zai planting) occurs on the most degraded land. One farmer, on the contrary, held the opinion that zaI had more impact on moist, fertile land. Neither the position of the zaI plot within the toposequence, nor the number of years that the parcel had been established, were considered factors determining yield.
Where the yield of a zdi parcel was not so good as, or even worse than the control parcel, the following explanations are proposed: Striga may have been present on the plot; sowing may have been late; the site was chosen badly (on a farmer house site, or in a water-logged depression). Another reason could have been failure to close over the zaI holes adequately.
The observations of farmers using za'i andmulch together are not conclusive. Some said that the mulch helped protect the young plants during a period of drought; others saw this as doubling the labor involved when doing both, and proposed instead to choose one or the other method, rather than combining the two. The choice of technique also depended on the availability of help, on manure supplies, and on the characteristics of the site. This will be discussed again later,
Twelve farmers did not try using zai in 1993. They said that they did not have manure, or that the family's labor was taken up mulching, building rock bunds, or clearing land, or that old age prevented strenuous work. However, 9 of the 12 declared their intention to use zai the following year ( see section 4).
Germination and reseeding. Germination was more successful in the zai parcels than in others: seedlings came up at a rate of 91%, as opposed to 77% in other parcels. All parcels were
threatened by a period of drought in the last two weeks of June. During this time, producers observed that the need to resow was reduced on the zaY parcels, where plants showed greater resistance to drought. For the whole sample, the zai parcels were resown 1.5 times; other parcels were reseeded twice. Figure 3 shows the number of producers who had to reseed zai or non-za'i parcels.
Resowing Parcels (number of producers)
. . . . . .. :. : .; . . . ... . . .
2 0 I ... . ...: ... . . . ... . .
................ ....... ....... . .
! ..............', X N ....... ...... ...........
0 Zai Control
f Jyes no
Zai parcels were resown less frequently, and by fewer producers. As has already been noted, germination was better in the zai parcels. It could therefore be concluded that zali parcels favor better germination. ZaY's greater resistance to drought was also brought out in comments made by farmers.
In assessing the need to reseed zai parcels, a number of factors were cited. These are summarized in Figure 4. Observations made by the farmers themselves complete this discussion.
Reasons Given For ReSowing Zai Parcels
zal made incorrectly.....
) 5 10 15 20 25 30 35 40
S% of responses
The drought affected all parcels, both zaf and non-zali. Its impact was felt more on the latter, but the difference between the two in terms of the area that had to be re-seeded was not calculated. The lack of practical knowledge concerning how to most effectively implement zai methods presents significant problems to those considering adopting such methods. Errors were made, for example:
Digging holes incorrectly: either not deep enough (so that seeds were washed away by rain); or dug too early (so that wind formed a hard crust on top, making it necessary to dig again, more deeply, before sowing). Also, sometimes, not enough manure was used. Sowing was done incorrectly in some cases. Instead of waiting for the first rains before sowing producers say that it is better to sow on dry soil. Sowing directly onto manure is not advised. Instead, soil and manure must be mixed well in order to promote deep root growth (otherwise, the plant will not withstand drought). Pests were often responsible for the failure of the first sowing. In particular, there were infestations of Striga in the parcel and worms in the manure. Shea nut leaves and debris blown by the wind blocked the holes.
Choice of sitemay also be a source of problems. If a parcel is located in the way of natural drainage, water washes the manure away. In low-lying areas, maintenance is too difficult. One site which was situated where there used to be a house suffered from soil that was both too dry and too acid.
Expectations from Zai parcels. Producers employing zai methods for the first time enjoyed an increase in productivity both in parcels that were already fairly productive, as well as in those parcels that had been degraded. Three quarters of those surveyed were expecting to improve production with zai. For the others, this represented a trial: new technology that was the talk of the village, and they took part in the trial for that reason.
For whatever reason given for trying zai at the outset, producers were clearly interestedin repeating the trial next year, as can be seen in Figure 5. The comments of both those who were and were not interested in the trial are recorded in the next section.
Trying Zai Next Year
(percent of responses)
No (11.9%)-- No Response (7.1%)
IV. PERSPECTIVES: GOALS FOR NEXT YEAR
What to do next year and where. Eighty one percent of producers are planning,to use zal next year. Of the five that are not interested, three decided not to try in 1993. Why not? Reasons for not trying include a lack of manure, or of manpower, or a preference for mulching., Two others did try in 1993, but were not satisfied with the results.
For the. remainder, za'i represented a breakthrough, to quote one participant: "'The RSP showed us how to reclaim exhausted soil "" The great majority of producers 'plan on using zai" next year, and use it on, larger areas (see Figure 6). Some producers plan on reusing last year's holes, taking advantage of the remaining manure left there.
Expected Size of the Zai Parcel in 1994
(in comparison to 1993)
Smaller (5.9%) Same (11.8%)
Larger (82.4%) Figure 6.
Factors that influence the choice of site are many (see Figure 7). In general producers start by tackling poor, dry soils, which yield almost nothing. Some producers have targeted the zi-, or koun koubris.
Expected Placement of Zai in 1994
(percent of responses)
with rock bunds
parcel near the house
low fertility soil
i i i .i X\U ikiERMj
0 5 10 15 20 25 30 35 40 45 50 Figure 7.
Gravel-based soil (well drained) sas osdrdaporae hr transport (of manure) is
a challenge, compound land is used for the zai site.
The predominance of mulching in Donsin indicates its importance. In spite of their satisfaction with zaY, farmers do not intend to abandon mulching.
Certain recommend using both zai and mulching together. For others, zai is more appropriate for use on the most unproductive parcels, such as zi-p616 land, and mulching is used for the remainder.
Inputs: Fertilizer. Equipment. and Labor. It is clear that the availability of manure and manpower in each family are prerequisites for the use of zai. Almost every producer expressed his intentions for next year in terms of a precise and pragmatic scenario comprising various activities which make competing demands on, his time. Work (involving either mulchcollection the construction of zaY or of bunds) starts in January and continues through until the first rains. The area involved is limited by the amount of labor available. Manure, compost and household waste are more or' less available, but ifit is necessary to go and collect manure from the fields that also takes time. The farmers therefore manage their limited resources according to a given strategy. Manpower becomes an issue especially when the number of able-bodied workers in the family is less than four. One result that is not without interest is noted in Figure 8, namely that farmers who come from the highest socio-economic class in the village do not experience the same constraints in this respect.
by socio-economic group
35' ------- -------------..... .. ..
The availability of manure to make za'i does not pose a problem for the majority of producers (see Figure 9). Animals, and especially small ruminants are numerous in Donsin. Even if one farmer does not have enough of his own animals, he can get manure from a neighbor, parent, or from pasture land. Some farmers have their own compost pits; others collect household waste. In any case, producers worry more about the problem of distribution than the availability of manure. This question is tackled in the discussion of the impact of zai in the future.
Expected Source of Fertilizer
for zai next year
No Response (19.0%)Waste/Refuse (12.0%),
" Livestock (69.0/%)
Producers are interested in using the appropriate equipment for preparing zal. Traditional hoes are not strong enough to dig the za' pits. Instead, it is suggested that ice-picks or Yatenga axes be used to make the task less costly.
Techniques of choice for successful zal. Farmers recognize the importance of mulch, rock bunds, and other measures taken to fight resource degradation such as earth bunds and scattering tree branches. Za'f is perceived as another such technique, but one which does not necessarily go with those mentioned above. Forty two percent (42%) of farmers have already used one CES technique on their land.
Farmers make their own suggestions for successful za' cultivation. For example, they recommend leaving ample space between rows to encourage plant growth. In addition, they recommend that zai pits should not be dug too deeply, since this tends to increase the worm population in the manure. Zai that are dug too closely together inhibit the growth of shoots. Lastly, manure is preferred to household waste.
The Impact of Zai on the Village. The farmers agreed almost unanimously that farming with zai would result in a reduction in the amount of land cultivated. The sheer demands zaYi makes on labor make it impossible to carry on cultivating the same surface area as at present. Moreover, the presence of rock bunds, or other CES measures will establish defined field limits. The farmers therefore foresee an end to itinerant farming. At the same time, the new methods would bring improvements to the soil.
A definite need for fertilizer is foreseen. Farmers talk of stalling their animals as one solution. However, one must admit that the local population did have a certain reticence to this method. This is most probably due to their concerns about how to feed their livestock. RSP experience has shown that the Donsin villagers are not interested in producing fodder. Sheepfolds, cited by quite a lot of villagers, are a realistic alternative for the production of organic material.
Donsin villagers consider making sturdier hoes. The RSP conducted tests on several models which had been made in Yatenga. At present, any model can be chosen and a copy made up by a blacksmith in Boulsa. The SANREM project also plans to help the Donsin villagers to develop appropriate tools.
Two further observations complete this discussion. Mutual aid group work in Donsin could resolve the labor shortage but this practice is not well developed in the village and its future development is uncertain.
Wandering animals prevent sowing at the beginning of the season. In principle, the village chief puts a stop to this when he considers it time to start sowing. If sowing is to be done before the first rain, wandering animals should be stopped earlier. The likelihood of this happening is equally uncertain.
The role of RSP. The villagers were consulted as to how the RSP and its collaborators (researchers, extensionists etc.) could best help them prepare the zai next year.
Typically this kind of question provokes a passive response, of the "give us this, give us that" kind. This kind of reply indicates a strongly felt need for the right equipment to prepare the za'i and was quite a common response in the village. More important still are those replies which manifest the villagers' constructive interest in making the best tools themselves or in improving the making of zai should the material and knowledge be supplied. (Diagram 10). Education figures prominently in the current role of the RSP in the village.
How RSP Can Assist Producers with Zai (percent of responses)
'- Equipment (74.0%)
The importance of strong hoes has already been mentioned. Wheelbarrows and carts are also important. A better functional knowledge was requested, i.e. how to make good compost, and knowledge of how to make the zaY themselves (specifications for digging the pits, how much manure to use, spacing, seeding, etc.).. Questionnaires recorded equally dynamic and concrete replies from farmers who sought further knowledge of agroforestry. There were also requests like "show our blacksmiths how to make the three-pronged hoe".
Conclusions and Recommendations. The interest of Donsin farmers in zaY has been firmly established. The villagers themselves decided to adopt zai technology on a trial basis, even without the intervention of the RSP, whose role was limited to such things as facilitating the "farmer to farmer" visit, demonstrating how to recuperate a zi-p616, and proposing that the 6 partners test zai-mulching. The intention to use za'i next year has been clearly expressed. A growth of 15% by comparison with this year can be anticipated. This would mean that 80% of villagers will use zai in 1994.
The advantages of zali for the population have been clearly expressed: the superior retention of moisture; better resistance to drought; good germination record as well as good yield; and the restoration of zi- (exhausted land). However, the ultimate adoption of this technology depends on its resource requirements, in particular the labor and organic matter required. Hence the necessity for each farmer to make his own evaluation according to his particular priorities and the availability of the required resources.
Action to be taken. For the RSP program, there are still details about zaY technology that need to be communicated to the farmers, because this will be indispensable to ensure future success. Providing answers, for example, to questions such as:
* How to obtain the best level of profitability on parcels of quality varying from fertile arable
land to eroded or "zi-p616l" parcels.
* Under what conditions is it better to mulch rather than use zai, or when should both methods
* In what form should the manure be and how should it be applied?
* How much reseeding is required with different zaf techniques?..."
Preparatory activities must also be considered, such as the availability of manure which implies animal management (stalling and feeding). Associated activities, such as the creation of rock bunds or agroforestry are also elements in this equation. Equally, there are actions to be taken to address equipment problems. The making of sturdier hoes, discussed above, is underway, as is the test of hand-pulled carts for transporting the organic matter.
Finally, the development of the villagers' awareness of the issues and methods is crucial. To date, the RSP plans a feedback session in Donsin, to be followed by a demonstration of the correct method for preparing zal. For this, organizers plan to use the "farmer to farmer"
approach again. Group testing is also appropriate, promoting collaboration in the form of association or grouping of farmers.
One farmer suggested that the RSP could help villagers if it provided "the goats and chickens that must be sacrificed In order to satisfy customary obligations" (and thereby ensure rain). The RSP does not have the ability to provide rain, but it can conduct research. RSP's goats are their on-farm trials, and their chickens are the education programs. The customary obligations that the RSP will help the villagers satisfy are those which restore the land for future generations, and which leave a legacy which ensures agriculture of a truly lasting nature.
Economic Analysis of Compost Production in Southwestern Burkina Faso
S. Amadou, M. Bertelsen, S. Ouedraogo
Soils in Burkina Faso, and more specifically, in the West are being continually degraded. This is due to a number' of factors, including the growth in surface area under cultivation as a result of emigration and the consequent demographic pressure on the land. At the same time, the withdrawal of input subsidies has meant that farmers have had to shoulder increasing expenses, while seeing their incomes drop.
There is ample research evidence that the use of organic matter, including the use of compost, contributes effectively to restoring soil fertility, whereas the continual use of mineral fertilizer ultimately leads to a loss of fertility.
However, very little is known about the economic aspects of composting. The latter should go hand in hand with the' research undertaken on technical aspects, with a view to'indicating the different users and eventually to directing researchers towards inexpensive innovations.
The object of this study is to make an economic analysis of the preparation of compost, as compared with the cost of buying mineral fertilizer, notably NPK, which is widely used. The projected results will:
Provide information for researchers and decision-makers on the chances of adopting
composting, considering the socio-economic difficulties which are associated with compostmaking.
Help interested farmers make the decision to adopt composting by making available to them
the socio-economic data collected.
* Contribute to the identification of new directions for research, including research on the use of
certain materials, with a view to reducing the cost of compost production.
Help lift any constraints which discourage the adoption of composting.
The site chosen for this study was the village of Kayao, situated in the Province of Mouhoun, in Burkina Faso. Kayao is one of the four sites chosen by the Western Zone Farming Systems Research Program (RSP), in the Western Zone of the Institute for Agricultural Study & Research (INERA- Institut d'Etudes et de Recherches Agricoles) of Burkina Faso's Western Zone.
As in most regions of Southwestern Burkina Faso, Kayao is a zone which receives significant immigration. According to INERA typology, it is representative of the Western zone's poorly equipped, cotton-producing areas. Cultivation methods are extensive ones, which under the pressure of emigration considerably reduces the availability of arable land; thereby provoking land conflicts between immigrants and indigenous peoples. (Oudraogo, 1991)
Moreover, because of the extension of cultivated areas and the reduction of fallow land, Kayao lands have mostly been degraded, or are on the way to becoming so. (Sanou, 1991)
In order to address the challenges in this zone, the RSP has put in place a system which integrates crop and the livestock, production systems. This was done by testing feeding regimes on draft cattle and compost making.
In order to evaluate the profitability of compost by comparison with mineral fertilizers, aquestionnaire was prepared which was designed to collect data on compost production. Researchers conducting the survey held weekly interviews with participating farmers to collect information on the following variables:
e labor involved for all operations
a inventory of materials used
* number of animals
e types of inputs used
* volume of compost pits.
A total of ten participant-farmers were chosen, selected according to their willingness to invest in this technology and acquire or possess the required cattle and plant material. These variables were supplemented by secondary data (bibliography and price surveys).
The infrastructure and the research technicians already in place enabled us to conduct these surveys with ease.
The research hypothesis is that the cost of soil improvement with compost is less than that with mineral fertilizer, and that the latter could be used more efficiently as a complement to, rather than a replacement for compost..
Equipment. The acquisition of appropriate materials constitutes the principal difficulty involved here. In fact, the necessary investment in materials for the first year appeared to be very costly for farmers whose income is limited. According to our data, acquisition of materials amounted to about 90,600 Fcfa. However, most farmersalready possessed at least some of the necessary
tools, including carts, dabas', mattocks and buckets. By deducting the cost of materials already in the possession of the farmers, the cost of materials that still had to be bought amounted to 13,000 Fcfa. The latter represents the price of an pick, a spade, two basins and a barrel, none of which were generally owned by the farmers.
However, the annual depreciation cost is low given the long life of materials and the compost pit. In addition, some tools, such as the pick, are mostly used only when digging the pits.
Water. The survey makes clear that the availability of water constitutes a barrier to composting. Most of our participant-farmers were unable to follow the recommended composting techniques because of lack of water. According to the survey, the nearest water source was approximately 6 kilometers from the village where the compost pits were located.
Labor. The survey reveals that two kinds of labor are used including family members and paid labor.
The participating farmers depended on hired labor more for digging the pits (46% of total digging labor time) than for filling the pits. Only 4% of labor for filling pits was hired.The table below indicates the average time spent, in man-hours per cubic meter, on digging and filling operations, respectively.
Table 1. Average labor time for production of one cubic meter of compost in'Kayao. Task ]Labor time (Hours) Standard deviation
Digging out pit 8.88 2.48
Filling in 7.18 1.5
Number of observations = 10
It is clear from Table 1 that digging timevaries greatly. The cost of digging is estimated at 165 Fcfa/m3. The cost of filling is estimated at around 19 Fcfa per hour of digging, averaging out costs for the duration of the operation. Even if this figure appears to be very low, in comparison to the opportunity cost (100 Fcfa) during the field work, this was expected, because the digging operation took place during the "hungry season. Sidib6 (1993) found an even lower opportunity cost, for female labor (10 Fcfa per hour) in the village Yasso, in Kossi province situated in Southwestern Burkina Faso.
Analysis of the compost production costs: Hypotheses of the analysis.
SThe pit is assumed to last for five years.
* Equipment depreciation.
dabas are short handled hoes used in Africa
Table 2 indicates the projected equipment lifetime and the rate of use of the equipment for compost production. These elements served as a basis for calculating straight line depreciation.
Equipment Price (Fcfa) Number Replacement Rate of use Depreciation
__________ _________ 1rate/year I M (Fcfa)
Pick 3,900 1 2 years 10% 975
Mattock 400 1 1 year 100% 400
Spade 1,000 1 5 years 100% 200
Basin 5,000 2 2 years, 100% 2500
Daba hoe 800 2 1 year 100% 800
Bucket 1,500 1 2 years 50% 375
Cart 75,000 1 5 years 10% 1500
Barrel 3,000 1 5 years 50% '300
Opportunity cost of labor. For the digging, the labor cost used reflects the actual amount paid'by producers, that is 165 Fcfa/m3. To estimate the cost of filling in the pit, the opportunity cost of labor in Kayao was used, i.e. around 100 Fcfa throughout the cropping season. It is recommended that the compost pit be filled during the cropping season so that it can benefit from rain water.
Estimates of the amount of time taken to empty the pit were not available when the analysis was made. It was therefore assumed that the length of time taken to empty a pit was equivalent to half the time taken to fill it, i.e. 3.59 hours/m3 The same applies to time taken to transport and spread the compost, for which secondary information was used.2
Comparative analysis of soil amendments. Table 3 shows that the production of one cubic meter of compost requires an investment of 2,476 Fcfa. To obtain the recommended amount of compost per hectare3, which is 2.5 tons (CFA, 1991) requires an investment of 26,914 Fcfa (see Table 3). According to Segda (1991), crop yields comparable to those obtained using the above amount of compost were obtained in Sourou by using 300 kg/ha of NPK, at a cost of 28,500 Fcfa/ha, with subsidized NPK priced at 95 Fcfa per kg.
Table 3. Production costs of compost per cubic meter, in Kayao. Category Costs (FCFA)
Labor (digging)5 33
2 Based on INERA/RSP Western Zone data on agricultural labor times.
3 hectare = 2.471 acres
4 Depreciation costs of equipment which lasts for the same length of time as the pit (5 years).
5 Time taken to dig ( 8.8 hours) x primary tillage costs (19 Fcfa per hour)/5 yrs.
Burkina Phosphate 552
Given the transport and spreading costs for both fertilizers, Table 4 shows that there is very little difference between the investment required when using NPK as opposed to compost, at least for the first year of use, i.e.: '28,054 Fcfa for compost, and 28,614 Fcfa for NPK.
However, Segda (1991) has pointed out that compost remains effective for a two-year period. On the other hand, if mineral fertilizer is to be the sole soil amendment, it has to be applied annually.
To establish a proper comparison between investment costs, ,they must be actualized. Table 4 therefore shows the actualized costs of using NPK or compost, respectively, as soil amendments. This is based on the assumption that the capital opportunity cost is at 1000%9.
Table 4. Comparative amendment costs: NPK versus Compost. Category Compost NPK
_ __ (2.5T/ha/2yrs) 10 Kg/ha/year
Production or Purchase 26,914 28,500
Transport to field (5 kin.)12 912 57
Spreading over 1 ha. 228 57
Total 28,054 28,614
Present value (c.op.1,000%)13 28,054 2,60114
6 10% of production cost
7 Time taken for filling (7.18 hours) x opportunity cost of labor (100 Fcfa per hour). Depreciation costs of equipment whose lifetime is shorter than that of the pit (5 years).
9 This hypothesis was based on the results of Lowenberg et al. (1993) which indicated that most of the small lucrative activities had an annual rate of profit of about 1000%. 10 Calculation based on the assumption that one pit, with a volume of 10.87 m3, to produce the recommended amount of 2.5 tons/ha of compost, which remains effective for 2 years. Recommended amount in order to obtain the same yield as produced by 2.5 tons of compost. 12 Calculated on the basis that 16 carts-full of compost, each of which takes an average of 1.30 hr. to transport to the field.
1 Opprtunity cost of capital.
1 Present value of the cost ofNPK, for the second year.
Table 4 also shows that the comparative investment cost between these two amendments is only very slight. One notes that the cost of compost in this case is only 10% lower than that of NPK. The difference is approximately 3000 Fcfa.
In some cases, a discount rate of 1000% seems very high. This is why Table 5 shows the costs of NPK and compost, at several levels of opportunity costs (40%, .100%, 500%, and 1000%). Table 5 shows that there are very significant differences, related to the various opportunity costs. For an opportunity cost of 40%, for example, the amendment cost of NPK appears to be almost twice as high as that of compost (28,054 Fcfa for compost, as opposed to 49,053 Fcfa for NPK). Even so, Table 3 indicated that there was very little difference between these costs when the opportunity cost is at 1000%.
Table 5. Comparative costs of amendment: NPK versus Compost, 'according to opportunity cost
Capital opportunity 40% 100% 500%
Compost 28,054 28,054 28,054 28,054
NPK 49,053 42,921 33,383 31,215
The economic analysis of compost production shows that, regardless of the bio-physical soil improvements, the use of compost for soil improvement is also more profitable than the use of mineral fertilizer (NPK).
However, this profitability is strongly influenced by the opportunity cost of capital. It is therefore very important to factor in the latter as decisive when calculating the present value of the cost of NPK. (The present value of the investment in NPK was used because two investments in a twoyear period produce the same effect as only one investment in compost over the same period). Thus, the relative profitability of composting diminishes when costs of capital run very high (at 1000%, for example).
In-spite of the fact that the financial profitability of composting has been demonstrated, there still remain other obstacles which may hinder its adoption.
There are obstacles linked to the difficulties of acquiring the necessary equipment to make the
compost pits. These obstacles are mostly due to the high investment required relative to the
low incomes of producers, and to the fact that some equipment is used only the firstyear.
However, this second problem could be solved by buying and managing equipment
* The scarcity of water during the dry season constitutes another obstacle to adopting
composting for soil amendment. In fact, the distance from water sources is discouraging for
all but a few producers, who must first of all supply their own needs. It is indispensable that
the decision-makers consider the problem of water availability as one which not only involves
ensuring supplies for the population, but which is also vitally linked to improving soil
* The many interviews with producers revealed that a large proportion of them were unaware of
the method and effects of composting. They preferred to wait and see for themselves the
effects on soil fertility of this first trial of composting, that they would then compare with their
own practices using manure from livestock corrals. It is therefore necessary to emphasize the
importance of training and information using demonstrations.
G.F.A. 1991. Les perspectives de la culture attelde au Burkina Faso. Annexes.
Lowenberg-DeBoer, J., Tahirou Abdoulaye, and Daniel Kabore. 1993. The Opportunity Cost of
Capital for Agriculture in Sahel: Case Study Evidence from Niger and Burkina Faso.
Oudraogo, S. 1991. Influence des modes d'acc~s i la terre sur la productivity des exploitations
agricoles: le cas de la Zone Ouest de Burkina Faso. Thesis. University Nationale de la
CMte d'Ivoire/Centre de Recherches Economiques et Sociales
Sanou, Patrice. 1991. L'insertion spatiale des producteurs agro-pastoraux dans la Zone Ouest du
Burkina: cas deDimolo, Kawara, Kayao, Yasso. Rapport d'activit6. INERA/RSP zone
Ouest. [Activity report. INERA/RSP Western Zone].
Segda, Z. 1991. Contribution la valorisation agricole des r6sidus de culture dans le Plateau
Central du Burkina Faso. Inventaire des disponibilitis en matibre organique et 6tude des
effets de l'inoculum Micro 110 IBF dans la pratique du compostage.
Sidib6, A. 1991. Analyse economique de quelques activities des femmes lids i l'utilisation des
produits forestiers non ligneux dans la zone Ouest du Burkina Faso. Communication
pr6sentde au symposium sur les parcs agro-forestiers des zones semi-arides d'Afrique de l'Ouest. [Paper presented to the Symposium on the Agroforestry parklands of the SemiArid Zones of West Africa]. Ouagadougou, Burkina Faso: 25-28 October 1993.
Use of Unconventional Products in Animal Health Care: The Case of Draft Animals in Burkina Faso
A survey conducted in 1990 in the four Western RSP village sites revealed a large cattle herd size in these villages. Herds of the two cotton-producing sites, where animal traction is widely used, include a large number of draft oxen (Badini 1990). The survey shows that no veterinary services are available in any of these villages. The national vaccination campaign is conducted every year in the villages between February and June.
During the agricultural season farmers are nevertheless faced with animal health problems during the agricultural campaign, which require assistance from a livestock or veterinary professional. In principle, farmers have had no training in primary care of animals and should consult a veterinarian. However, the closest animal health station is about thirty kilometers away from the village. What do farmers resort to during the agricultural seasonwhen their draft oxen are ill?
In order to address this question, a preliminary survey was conducted in Kayaol, one of the RSP villages, which represented a sub-zone characterized by subsistence cropping with some cotton production and a high rate of animal traction in 1990. There are 223 draft oxen, 88 donkeys, and 1189 cattle, in the village and 34 % of the villagers use animal traction (Badini 1990).
The objectives of this survey were to:
* Gather knowledge on farmer practices,
* Inventory the unconventional products used for draft animal health care,
* List the supply sources for these products, application methods and treatment costs.
Data was collected through informal interviews with farm family members possessing draft oxen. The interviews especially focused on young individuals who work with these animals and maintain them. These individuals monitor the behavior of draft animals and know them best. The survey was initiated during the 1991-1992 season and was completed in January 1994.
A questionnaire was used throughout the survey. However, it should be noted that this questionnaire was not uniformly administered because some questions dealt with sensitive issues. Most people interviewed found it difficult to answer the questions, sensing that they had to
Survey participants: Sanou Sogo and Dabilou Salam, technician-enumerators Fandi6 Kankdki, ,village enumerator
compromise their own interests. Clandestine vaccination is normally prohibited in Burkina Faso. Therefore, a combination of interviews and direct observations of farm practices was used.
Every year, the selected sample included 25 production units using animal traction and participating in RSP tests. However, observations were made on all farms having draft oxen.
Disease diagnosis by farmers. Farmers use their experience as a basis for, diagnosing animal diseases. 'They do not have the necessary knowledge of specific pathogens, but, often recognize aggravating factors such as change in climate, diet, work schedule, etc. Once an animal displays an abnormal behavior such as sadness, fatigue, lethargy, refusal of food, etc., farmers examine the animal (body temperature by touch, feces, eyes, snout, hair, nasal secretions, etc.). More knowledgeable farmers are called upon to determine the cause of the disease when they cannot do it themselves.
Reasons for the use of unconventional products. The survey results indicate that
*To call the livestock Agent of the village of Oronkna to Kayao is rather difficult, because appointments are often missed and the agent is often in field missions and so cannot be, easily
found at his office2;
*Rarely can the prescribed remedy be obtained, at the, livestock extension station. Therefore, farmers have to go to a larger center such as the CRPA at,90 or 190 km distance. This causes.
a delay between the time of the visit and the beginning of the treatment. Additional problems arise when farmers cannot procure the product, (because products are frequently out of stock)
or when subsequent services of the agent are required, as in the case of injectable products.
Problems which discourage farmers from using conventional products are in order of importance:
*Difficulties of access to conventional products (70%)
*Unavailability of the livestock extension agent (20%)
*Confidence in unconventional products (10%)
Products used. Products used to treat draft animals are of various origins. They include drugs, pesticides, antibiotics and other illicit pharmaceutical products.
Table 1 indicates that none -of the products used is specifically intended for animal care. Most pharmaceutical products are fraudulently imported from, Ghana. They are confiscated by the police during checks of the local markets.
One of the advantages of unconventional treatments for farmers appears in Table 2. Treatment cost varies between 30 and 250 Fcfa, which is inexpensive relative to, conventional treatments and, affordable to those raising cattle.
Antibiotics are all called "toupa'l" (literal translation); This is because they are used to care for all diseases. They are of two kinds: Totapen and tetracycline, both in capsules.
Paracetamols identified are of several sorts:
* Daga: package of three 500 mg pills
* Alagme: package of twelve 500 mg pills
* Phenic: Paracetamol in 500 mg and 250 mg dosages, The range of paracetamols is quite broad.
Table 1. Percentage of farmers interviewed having used one of 6 unconventional
products at least once to treat 8 frequent diseases (N=25)
Fever Diarrhea Wounds Skin Fatigue Skin General ill
fever D 'parasites disease being
Antibiotics 75 77 -- -- 25 95 80
Paracetamols 70 25 10 -- 61 28 96
Daga, alagme __..
Sumicidine -- -- -- 98 -- -- -"Dissolution" -- -- 84 -- -- -- -Instant coffee -- -- -- -- 11 25 -Undetermined 5 -- -- -- -- -- 6
other "aNineteen farmers, for example, out of 25 (75%) said they used antibiotics against fever. blnsecticide used in cotton production
cManufactured to repair bicycle inner tubes
Table 2. Description of unconventional products and their costs Disease Product Form/Unit Unitcost Dose Cost
(F CFA) (F CFA)
Fever Totapen Capsule 25 3 75
Fever Tetracycline Capsule 15 4 60
Fever Daga Pill 50 2 100
Fever Daga Pill 50 2 100
Fever Alagme Pill 25 4 100
Diarrhea Totapen Capsule 25 10 250
Diarrhea Tetracycline Capsule 15 14 210
Wounds "Dissolution" Bottle 150 1. 150
Skin parasites Sumicidine Water jug 5000 <<1 200
Strepto-trichosis Totapen Capsule 25 6 150
Skin disease Coffee Packet 30 1 30
Gen. ill-being Tetracycline Capsule 15 8 120
Gen. ill-being Totapen Capsule 25 4 100
Directions for use. The directions for use of products depends not only on the manner they are administered but also on the disease to be treated, as one product can be used for the treatment of several diseases.
Products can be orally administered in three ways:
e Diluting it in drinking water. The animal is left for-some time without drinking water, then,
once thirsty, given a reasonable quantity of product-water mixture to be entirely drunk. e Forcing the animal to swallow the entire product by pulling on its tongue
* Mixing it in food. This method is little used because of animal refusal.
The most widespread practice is intra-muscular injection in the shoulder or flank is also used. Some "specialized" farmers being especially skillful are called upon for injections. Two'solvents are used to dilute products. Water is most widely used. Drinking water is used without any special treatment. It is not boiled nor filtered. "Koutoukou", an alcoholic drink derived from sugar distillation, is also used by some people. It is a popular drink and is sometimes called "who pushed me", or "zonzon", or "patc6". A liter of the sort with high alcohol content (about 90 degrees) costs 500 Fcfa, while the sort of low alcoholic content (9 to 20 degrees) is sold for 300 Fcfa a liter. The latter type is used as a solvent.
Syringes are generally designed for a single use, but they are used repeatedly until useless. Syringes sold in pharmacies have a capacity of 5 to 10 ml. When animals are familiar with the person doing the treatment, it is petted on the head for an easy intra-muscular injection. Otherwise, the animal has to be immobilized by the head or taken down.
Example of preparation of injectable products against fever. The origin of the fever is generally not identified. It is noted that the animal is sad with bristled hair and high body temperature. The treatment includes tetracyclines and "daga" paracetamol diluted in a bottle of "koutoukou" or water, which has to be strongly shaken for proper mixing. The solution is pumped into the syringe without the needle. Air is drawn out of the syringe before the intra-muscular injection.
In general, the dosage used is not well defined. It varies according to the person administering the treatment, the stage of development of the disease and the age of the animal.
Examples of products for external treatment.
Wounds. Mostly used for this purpose is the "dissolution", a glue product used to repair cycle inner tubes. It is an aseptic wound dressing. This product replaces, Synexa and K'otrine more and more frequently. The glue is applied on the wound in a thin layer. A few moments later, the product is dry and protects the wound from flies and other insects. The dressing is repeated until the wound heals.
Tick control. There are two products used against ticks; both are pest control products used in cotton production: Sumicidine and decis. The first method consists in mixing eight to ten
volumes measured with a peanut shell (7 to 10 ml) in a bucketful of water and spraying the mixture on the body of the animal with a backpack sprayer. In the second method, fresh cattle feces are kneaded in the chemical liquid and the animal is coated with this paste.
General fatigue. The animal is tense. It cannot stand sustained effort. In order to give him a boost, three "daga" pills are administered orally or by injection.
Therefore, the main diseases treated which are commonly encountered are affections that do not require the intervention of a livestock specialist, with the exception of skin streptotrichosis.
Vaccination accidents. These medication practices are not without consequences. The use of products or treatment equipment can be traumatic to animals.
Solvents. Water used as solvent is not treated in any special way and may come from questionable sources. It may contaminate animals with other diseases.
Products. Antibiotics of unknown origin without written directions and known expiration dates may be dangerous. The use of bacteriostatic or bactericidal chemicals without the advice of a veterinarian can be overdone. Potential results include accidents and resistance to antibiotics.
Syringes. These can be sources of trauma and infection to animals, as they are not disinfected beforehand and are used repeatedly. Interviews revealed that there are accidents due to injections:
* Bleeding. A poorly practiced injection may result in bleeding which can then turn into
* Oedema. There is swelling where the injection was done. It can worsen and cause an abscess.
Animals may even have reduced mobility on the side of the leg affected by the injection.
Interviews indicate that in order to care for their draft animals, farmers develop their own strategies and use fraudulent pharmaceuticals, pesticides, and other products (coffee, glue, etc.). The difficulty of access to veterinarian services and the high cost of conventional remedies (including transportation costs to Didbougou or Bobo-Dioulasso) on one hand, and, the availability of products and solvents (water, local alcohol) and of soiled equipment (used syringes) on the other hand make these practices easier and help to perpetuate them. Even though these practices are applied to animals, they give rise to serious problems for farmers and risk the health of their livestock.
References Badini, 0. 1990. Census of livestock management systems of Western Burkina Faso. RSP Western Zone Report.
Evolution of Sedimentation, Surface Micro-Morphology, and Millet Production in Response to Soil Conservation
Practices on an Eroded Site at Yilou, Burkina Faso
N. F. Kambou, S. J.-B. Taonda, R. Zougmorb, B. Kabor6, and J. Dickey
Land degradation is widespread in Burkina Faso. Approximately 24% of the country's land area is highly degraded, and most of this land is concentrated in central Burkina on the Mossi Plateau (Figure 1). Current land management practices and population pressure contribute to the high rate of arable land degradation, and therefore threaten environmental quality and food security in the short and long run. Applied research in the area of on-farm soil and water conservation is a priority activity of the Water, Soils, Fertility, Irrigation, and Agricultural Machinery program of the National Institute for Agricultural Studies and Research.
Degradation zones in .
MALI o NIGER
*K~'UDUG~UFAA O'GOURMA PAG
osooOULASSO .... P ECHELLE
. .... .. ..... .. O 50 100 Km
Legend Pattern Degradation Land area Intensity km2 %
None 75 775 28
.. ... .. Low 50 982 19
S." Moderate 80 615 29
COTE D'IVOIRE High 66914 24
Total 274286 100
Years of farming without adequately protecting land from intense rainfall and runoff have resulted in formation of extremely dense, bare surfaces capped by a one-to-two-cm-thick crust. These areas are known locally as zi-pel6, or literally "white places". A number of soil
reclamation practices have been successfully applied by farmers to these sites.- Three of the most successful practices are:
* Rock bunds placed on the contour to slow runoff and encourage sedimentation
* Mulching with grass or crop residues to protect the soil surface from raindrop impact,
encourages termite activity and porosity, reduces evaporation, and adds some organic matter & L which are small holes that are filled with manure or compost, and then seeded with a
Usually, a single practice is applied to a'given land area, or rock bunds are combined with one of the other practices. Our objectives were:
* To begin to describe the mechanisms, rate, and extent of soil reclamation effects above and
just below the first rock bund in a watershed
* To evaluate the impact of mulching and zai, alone and in combination, on soil surface
condition and millet production
The sites chosen were zi-pel6 (2% slope) at Yilou and Nioniogo (Figure 2), where highly variable annual rainfall averages about 600 mm (Figure 3). In general, the soil was approximately 30 cm of very compact sandy loam over a laterite pan. A (laterite) rock bund of about 30 cm height and 100 m length (Figure 4) was constructed on the contour, and an area (downhill) was fenced off for cultivation, since zi-pel receive a great deal of domestic animal traffic during the growing season. The following soil management treatments were applied during the 1991 to 1993 seasons at Yilou in three randomized complete blocks (RBCD's), and in 1993 in 4 RBCD's at Nioniogo inside the fenced areas (Yilou site shown in Figure 4):
Direct sowing into the bare soil
* Grass mulching before sowing
* Zai" dug on an 80 cm x 80 cm square grid (zai" in lines), then grass mulching Zai" dug on an 80 cm x 80 cm square grid
* Zai" at a similar density, but scattered irregularly
On each plot at Yilou, the same treatment was applied in each of the three years. Millet stover from each plot was harvested, stored, and reapplied to the same plot just before the next season. The millet variety IKMV-8201 was planted each year. All plots received 100 kg/ha of 14-2314-6-2 (N-P-K-S-B) at planting and 100 kg/ha of urea (46-0-0), for a total of 60-23-14-6-2.
Weeds were hand-pulled before they competed with the crop during 1991 and 1992 at Yilou and in 1993 at Nioniogo. Weed pressure at Yilou in 1993 required a weeding with a hand hoe. Soil surface condition and sedimentation were observed in the plots after the 1992 season at Yilou, as was millet growth and yield in all years at Yilou and in 1993 at Nioniogo.
TEST LOCATION 40 I I I I _I
0 KONGou 120
Ni ogo YILOU
-- -- M-ANE 20
0 _. >" C >,
~~~~: Yio 92 oa 0 Z
To Ouagadougou Yilou 1992, Total 510 mm Site Location Median per decade
ouaoaV0u Fad. N gourm
_ 20th and 80th percentiles at Man6 1970-1990
SMain road, year-round practicability. Average Total Annual Rainfall
Main road, intermittent practicability. 1970-1992 = 616 mm, Mand
Secondary road. 1962-1969 = 762 mm, Mand
-- - Test Location
SOURCE: IGN, 1959, TOPOGRAPHIC MAP OF WEST AFRICA, 1/500,000
Figure 2. Figure 3.
After the 1992 season, we described the sedimentation and micro-profiles in 5 shallow soil pits
on a 30-m transect above the two-year-old rock bund at Yilou (Figure 4).
. . . ..1
V. . T
SFirst replication pj : '. Ru Second mplhation
Rt Third replication T Control plot T. Zal
T3 Mulching T4 Zal + mulching T Scatterd zalI Clay and silt deposits Plant cover
Clay and gravel deposits gravel pavement Bare, eroded surface
gravel pavement with seal
III. RESULTS AND DISCUSSION
The pattern of sedimentation uphill from the rock bund at Yilou was approximately as follows (Figure 5):
SEDIMENTATION FRONT UPHILL FROM A ROCK BUND, YILOU, 1992:
Profile 5 Profile 4 Profile 3 Profile 2 Profile 1
Rock Bund Organic matter made up of algae under
______L..__::_ Clayey plasmic horizon creating an
15 erosion crust.
Z Coarse elements (gravel).
Clay, silt and fine eS nd mixture with L organic matter.
f~:~1 Clay, alt anid aand mixture with 10% LL J coarse elemental.
Hyper proportion of coarse elements 4- (over 30%).
Profile 1 (0. 81 m from bund): Several mm of clay underlain by layers of silt and fine sand to 5 mm, fine and medium sand layers to 10rm. Underlain by gravelly sandy loam. (Figure 6).
HORIZONS Profile #1 (0.81 m from rock bund)
-2 .!! i;S! ~ !!i.. .. .. .. 10ms HOrio e c ito
....: : ..... 1- Sedimentation layer made up of sorted sand: from top to
bottom clay, silt and fine sand Color 10YR 6/3 Thickness
S'" 2 Sandy layer: Thickness:5mm
S .. 3 Mixture of clay, silt, sand and 30 to 35% coarse
10 YR 6/3 Thickness: 85mm
4 Mixture of clay,, silt and 25% coarse material.
10 YR 6/6 Thickness: 235 mm
4 5 Rock pan
, I 1 1330 mm
Profile 2.(6.2 m from bund): Laterite pea gravel to 8 mm, underlain by a 0.5-mm clay deposit, another 4 mm of fine sand, and 10 mm of sandy loam with significant organic matter, for a total depth of 22 mm. This underlain by gravelly sandy loam (Figure 7).
HORIZONS .... .. o i 6d
1 ..... . Profile #2 (6.2 m from rock bund)
2 -.o 8mm
3 ......:: 12 mm Horizon description
4 ...... ....1 Coarse gravelly material
........... 8m m
2 Plasmic film of clayey texture.
Color: 10 YR 7/3 size: 0.5 mm
5 3 Fine sand on sorted material.
10 YR 5/3 size: 3.5 mm
* 170 mm 4 Mixture of silt and fine sand with high organic matter
190mm 10YR 6/2 Size: 10mm
5 Mixture of fine (clay, silt and fine sand) and less than 10% of coarse elements 10 YR 6/3 Size 168mm
6 Coarser elements than in 5. Transition zone with change S -of color
250 mm '10 YR 6/6 'l = I ', ;, 250 mm
7 Higher (35 to 40%) proportion of coarser elements.
8 10 YR 6/4 Size: 60mm
8 Rock pan
10 YR 6/6
Profile 3 (27.7 m from bund): Pea gravel scattered thinly on top of 15 mm of massive, sandy
loam, the surface sealed in a crust of very low porosity. This over gravelly loam (Figure 8).
HORIZONS 0 Profile #3 (27.67 m from rock bund)
1 Highly compacted clayey layer (Thickness = 15mm).
Erosion crust preventing all infiltration. Plasmic horizon. Presence of roots of 10 YR 5/8 color Horizon color = 10 YR 6/2
" ", 85 mm 2 Thickness = 70 mm. Over 60% coarse material. Clay
silty cement with organic matter. Grey color = 10Yr 6/3
3 3 Thickness = 70 mm. Over 40% coarse material. Claysandy cement with organic matter. 10 YR 7/6
4 Rock pan with ferruginous modules. Thickness = 75 mm 155 mm 10 YR 7/8
SProfile 4 (40.8 m from bund): Massive sandy loam to 25 cm, the eroded surface sealed. This overlaying gravelly sandy loam (Figure 9).
HORIZONS Profile #4 (40.81 m from rock bund)
1 Horizon description
...... 25 mm 1 Highly compact clayey layer forming an erosion crust preventing all infiltration. Plasmic horizon. Thickness 25 mm
* Color 10YR5/2
S.2 -- Thickness = 60 mm. Over 60% coarse material. Clayas mrsilty cement with organic matter. Grey color 10 YR 6/5 85mm
3 Over 40% coarse material. Clay-silty cement.
Thickness= 115 mm
S. 10 YR 6/4
4 Rock pan Thickness = 60 mm 10 YR 7/6
Profile 5 (50.8 m from bund, beginning to leave the zi-peld): Surface layer (4 mm) of organic material, including algae under a layer of low, dead vegetation. This underlain by 12
H Z mm Profile #5 (50.81 m from rock bund)
2 Horizon descriptions
16 mm 1 4 mm thick micro-horizon. Organic matter made up of
Color 1OYR 4/2
96mm 2 Clayey plasmic horizon Thickness = 12 mrn 1 0Yr 5/3 3- Mixture of clay, silt, sand and 30 to 40% gravel.
Thickness = 80 mm Roots 10YR 6/3
200 mm 4- Thickness 104 mm. Horizon layer is darker than horizon 3 and lighter than horizon 4. 5% small gravel. Kaolimitc clay of 1/1 type
s 10 YR 4/3
I I I
260 mm 5- Rock pan. 40% or more small gravel 10 YR 7/6
6 6 Horizon harder than horizon 5. Laterite.
mm of clay loam. Gravelly sandy loam begins again at 16 mm. First presence of plant tops
or roots in transect (Figure 10).
Most of the deposits that can benefit plant life are within a few meters of the bund. This zone gradually gives way to the sealed, massive, eroded surface that characterizes the zi-pel&, which in turn gives way to surfaces covered with some topsoil at the top of the zi-pel&.
Below the rock bund, the erosive force of the water is reduced, but the surface conditions created by the soil and water conservation treatments in the trial influence surface characteristics and how much of this water actually infiltrates. The surface soil conditions in the 5 treatments can be summarized as follows:
- Direct sowing: Massive, sealed, eroded surface remains, some gravel deposit on surface.
0 Grass mulch: Surface protection by the mulch and termite activity under the mulch allowed
rehabilitation of porosity in the surface layer, and there were several mm of deposition of
clay to fine sand.
* Zai" with grass mulch: Conditions between the zai much as above, but surface local to za"
had higher porosity and reduced crust formation, and of course higher organic matter.
* Zai" in lines: Surface local to zai" had higher porosity and reduced crust formation, but this
effect was less than where zai' were combined with mulch. Areas between lines of zai"
eroded, massive, sealed.
* Scattered zai" Much as above, but scattered zai" seem to, slow surface flow enough to
increase deposition and reduce crusting of surfaces between zai.
Only rainfall data for 1992 at Yilou is available. Total annual rainfall in 1992 (510 mm) was well below the post-1969 average of 616 mm (Figure 3). Dry conditions were primarily at the beginning of the season, when rains began some weeks late, and during two dry mid-season decades, one in mid-July and one in mid-August. Such conditions provide an opportunity to evaluate the ability of soil and water conservation measures to reduce crop drought stress.
Yield and harvest index means and mean comparisons for individual site/years and for all 4 site/years grouped together are presented in Table 1. In general, all treatments but direct sowing allowed for locally acceptable levels of cereal production on this otherwise baren land. The various levels of grain and stover productivity indicate the rate of site reclamation for crop production under the various practices. Table 1 also presents F values and probability levels for comparisons among groups of treatments. The nature of these comparisons is illustrated in Table 2 for the example of grain yield in the combined analysis. In the example, an F value of 80.8 is associated with a probability level of less than 0.001 for the comparison of direct sowing with all other treatments taken together, suggesting a clear difference between grain yield under direct sowing and under the other treatments. The only other comparison that is significant for that analysis was between aligned and nonaligned zai" (F=6.8, P=0.03).
Table 1. Yield and harvest index means and mean comparisons for individual and grouped site/years.
Grain yield (kg/ha) Stover yield (kg/ha) Plant height
Yilou Nion Tous Yilou Nion Tous Yilou Nion Tous
....iogo liogo l iogo
Treatment 1991 1992 1993 1993 Avg. 1991 1992 1993 1993 avg. 1991 1992 1993 1993 Avg.
Dirctvs. others 0 161 253 49 111 0 539 777 83 329 0 123 36 51
Mulching 0 1334 829 37 614 73 2038 1553 247 921 0 200 124 110
Zai & mulching 118 1553 680 232 449 1142 2084 914 1345 1369 137 202 165 168
Zallines 86 722 876 195 510 987 1170 1453 1492 1292 130 189 174 165
Zai not scattered 121 1084 1109 146 579 1854 2358 2328 2029 2133 139 192 153 160
Average 65 971 749 132 453 811 1638 1638 1039 1209 81 181 130 131
Comparison F value
L Direct vs. others 14.5 65.9 27.0 12.1 80.8 71.3 41.5 21.6 14.4 70.9 306.3 31.9 56.7 59.1 113.7
Mulching vs. 5.0 15.5 0.2 25.3 0.1 1.9 1.1 0.0 17.8 8.0 62.0 0.4 0.0 6.4 58.9
any zai _Zai+ mulching 19.6 10.0 5.7 3.5 2.9 105.0 1.4 27.9 1.4 5.1 448.5 0.5 38.9 0.0 0.6
Zailines vs.. 1.7 5.3 2.4 1.7 6.8 32.6 19.4 16.8 1.8 37.8 1.6 0.0 24.1 1.2 0.3
scattered zai '
Probability of an orthogonal comparison
Direct vs. others 0.005 <.001 <.001 0.005 <.001 <.001 <.001 0.002 0.003 <.001 <.001 <.001 <.001 <.001 <.001
Mulching vs. 0.06 0.004 0.6 <.001 0.8 0.2 0.3 0.95 0.001 0.02 <.001 0.6 01,98 0.03 <.001
Zai+ mulching 0.002 0.001 0.04 0.009 0.13 <.001 0.3 <.001 0.3 0.05 <.001 0.5 <.001 0.9 0.5
Zailines vs. 0.2 0.05 0.2 0.2 0.03 <.001 0.002 0.003 0.2 <.001 0.2 0.9 0.001 0.3 0.6
scatterd zai __
Table 2. F Probability of an orthogonal comparison Treatments Direct Mulching Zai'+ Zai in Scattered
sowing mulching lines ZaF
All years and sites
Grain Yield Direct Sowing _<.001
Zai in lines
The following observations can be made:
During 1991 at Yilou and 1993 at Nioniogo, none of the treatments produced much grain,
however stover production was mostly between 1000 and 2000 kg/ha for all treatments that
included zai; and less than 300 kg/ha for other treatments.
In 1992 and 1993 at Yilou, all treatments except direct sowing produced average grain yields
greater than 600 kg/ha. All of the treatments except direct sowing, therefore, can provide
acceptable levels of crop production under the rainfall and fertility conditions of this
experiment, but mulch alone cannot do so during the first year of reclamation.
Direct sowing means were the lowest in every analysis (except for grain yield of the mulchonly treatment at Nioniogo), and is not suitable for soil reclamation, even below a rock bund
with adequate chemical fertilizer.
Considering the grain and stover yields (stover is also of value for fuel, construction, and
basketry in Burkina), and the possibility to have at least some grain the first year, (100-kg/ha
grain yields are not uncommon in the region), the treatments with zai offer some advantage during early reclamation. If no fertilizer had been added (often the case in farmers' fields),
the relative fertility contribution of the zai" would probably have been more pronounced.
The combination of grass mulch with zai gave the highest average grain yield (1550 kg/ha in
1992), a truly astonishing level of productivity on this type of land by local standards. In a
drier year, the potential for superior water conservation by this practice (relative to za"
without mulch) might produce greater differences, making it a possible risk-reduction
farming strategy. This advantage is not sustained in all conditions as reclamation progresses,
and did not hold at Yilou in 1993.
There appears to be some merit in scattering zai" as opposed to putting them in lines (all three years at Yilou, not at Nioniogo), probably due to the elimination of wide, unobstructed interrow spaces for surface water flow.
The evolution of the soil surface above the bund included (1) deposition of several alternating layers of fine and coarse materials near the bund; (2) deposition of coarse materials, including gravels further away from the bund, and (3) formation of a surface seal on compact, eroded surfaces farther from the bund. In general, a significant increase in porosity of the surface layer was observed where significant sedimentation occurred, and the soil was beginning to support plant life again. Below the bund, zai augmented soil porosity and reduced crusting locally. Mulching encouraged termite activity, having the same type of effect as zai; but to a lesser degree and over the whole soil surface. Scattered za" increased sedimentation between zai. Millet production was between 0 and 250 kg/ha the first year in all treatments. In the second and third years of reclamation, yield relationships among reclamation practices varied, but all reclamation practices retained a clear advantage over direct sowing. Maximum average annual treatment grain yield was 1550 kg/ha.
Characterization of the Soil-Plant System in Bush Fields in the Tropical North Sudanian Region of Burkina Faso
S. J.-B. Taonda, J. Dickey, P. S'dogo, and K. Sanon
The economy of Sahelian countries is mostly based on traditional subsistence agriculture. There are two kinds of fields in the land management system of Burkina Faso, namely village and bush fields. Local organic inputs such as crop residues, animal droppings, household refuse or compost are applied on village fields which are located next to the residential areas. In rare cases, exogenous inputs such as mineral fertilizer are used there. More and more frequently, fields are protected from erosion caused by very intense rainfall events by erosion control practices. Production in village fields represents a minor part (10%) of total production.
Remaining crop production comes from bush fields. However, extensive agriculture based on nutrient mining is practiced. Fallowing used to be the only form of soil fertility restoration. In most Sahelian countries, demographic pressure has resulted in the reduction or elimination of fallow periods. In the absence of viable systems of fertility restoration, this land management trend has been accompanied by soil degradation.
Burkina Faso's lands are a part of this crisis, which is particularly acute on the Central Plateau, where 2 to 20% of the population (depending on the region) has permanently emigrated during the last decade (INSD, 1985). Emigration is directed toward neighboring coastal countries and especially toward southern and southwestern Burkina Faso. Migrants preferentially settle in less populated or newly settled zones where land is available and soils are fertile (Milleville, 1988).
In frontier zones, the intensive and extensive land management systems (of village and bush fields from the Central Plateau respectively) are replicated. Lack of means precludes viable application of intensive management of bush fields. The fundamental question to be addressed is the following: How can production be sustained while maintaining or improving land and soil resources? This question can only be answered by taking into account the socio-economic, biological, physical, and chemical dimensions of the dynamics of the soil degradation process.
Authors such as Nye and Greenland (1960), Charreau (1972), Siband (1972) and Pichot (1974) have studied changes in soil physical and chemical properties of cultivated and fallowed fields in research station and farm environments. This study focuses on on-farm soil degradation in a frontier zone of Burkina Faso's southern Central Plateau.
Hypotheses which underlie the study are the following:
A frontier zone presents the opportunity to analyze changes in soil physical and chemical properties at various stages of field evolution, whereas this process has run its course on
degraded lands, or has not yet begun on untouched natural lands.
* Diverse agricultural practices, which will induce different types-of field evolution, may
coexist in a frontier zone.
In order to control variability in the study, only bush fields cultivated with animal traction were selected. Most farmers in frontier areas use animal traction. Furthermore, intensification of production, which is becoming more pronounced, must rely on animal traction because labor availability is limited. Some farmers in the studied village cultivate by hand.
The objective of the first part of this study, which is discussed in this paper, is to characterize soil physical and chemical property changes during the years after clearing of cultivated soils on farms in semi-arid zone (700 to 900 mm of rainfall).
II. MATERIALS AND METHODS
Chemical and physical properties of soil were studied on a soil chronosequence.
The Soil "Chronosequence". Thiougou, a frontier village in the Southern part of the Central Plateau was selected. It is located between 11 *29' and 11 24' north latitude and 0'49' and 054' west longitude. A study of village soils was carried out and a physiographic map of the village was drawn.
Among the village's soils, modal leached tropical ferruginous soils (sols ferrugineux tropicaux lessiv~s modaux, probably Paleustalfs after U.S.D.A., 1975) were selected for this study due to their dominance of Thiougou's land area. Moreover, they are the most widely cultivated soils in the village and the surrounding region. A map of all village fields and fallows was developed, from which fields belonging to this soil mapping unit couldbe listed. These fields were grouped according to duration of cultivation, including fields of ages 0 (fallow), 1 (new field), 2, 4, 5, 7, 9 and 17 years. Several studies were undertaken on this chronosequence, including: x A study of soil physical and chemical properties on eleven farmer fields described in this paper x A study of soil productivity on 30 plots which will be reported elsewhere (Taonda et al., 1995).
Measurement Methods for Physical Properties. Bulk density was measured on undisturbed soil cores. Textural separates were measured by the Robinson pipet method and texture was characterized according to the textural triangle. Moisture content at various pF levels was measured by weight after equilibration on a membrane press. These samples had been sieved to less than 2 mm diameter and repacked into cylinders. Field moisture content was based on auger sampling and oven-drying at 105'C.
Roughness of the soil surface was measured using the Guillobez method (1991). In this method, a one-meter-long frame containing a series of moveable, straight vertical rods which can be freed to match the irregularities of the terrain is levelled above the highest ground surface along its length. The standard deviation of prodruding rod lengths as measured from the base of the frame provides an index of soil surface roughness. Measurements were replicated at three locations per observation date and in each plot. The first observations were taken
immediately after ridging and subsequently after each rainfall event. Runoff was measured from 1 m2 plots bordered by vertical tin sheets. Water from the runoff plots was channeled through a plastic pipe into an open barrel. Water depth in the barrel was measured after every rainfall event and runoff depth was calculated. Rainfall amount was measured in rain gauges adjacent to each plot. Runoff water depth was calculated as follows:
(Volume in barrel Volume of rainfall directly into barrel)/ 1 m2
Measurement Methods for Chemical Properties.. Soil pH (in water and IN KC1) was measured with a glass electrode in a 1:2.5 (by weight) suspension of soil and solution. The pH-meter has glass electrodes. Total carbon was obtained by the Walkley-Black method (Walkley and Black, 1934). Nitrogen was measured by the Kjeldahl method (Jackson, 1958). Total phosphorus was determined after Olsen and Dean (1965). Available P was obtained by the Bray I method (Dickman and Bray, 1941). Exchangeable bases and CEC were measured using the IITA Playsier (1978) method, in which exchangeable cations are displaced from exchange sites with a silver thioure (AgTu) solution. AgTu provides total soil saturation due to its preferential adsorbtion. Silver content in the extract is determined. The amount of silver retained in the soil, which indicates CEC, is deduced through comparison with a standard soil sample.
The Evolution of Soil Physical Properties. Table 1 shows that surface horizons in almost all plots were of sandy-loam texture according to the USDA classification. Plots of ages 0 and 17 years were of loamin to sandy loam texture. Bulk density was intermediate in surface horizons, increasing with depth on all plots.
The decrease in soil surface roughness is the difference between roughness after ridging before planting and roughness at the end of the season. This difference increased exponentially and reached a plateau of 15% reduction at around 7 years of field age (Figure 1).
Figure 2 shows that for plots of ages 0 and 17 years, the greater the rainfall event, the greater the depth of runoff from the plot. This figure also illustrates that the difference in runoff depth between old and young plots was large for large events. However, old and young fields lost a relatively similar water volume during small storms. The slopes of the first order polynomials relating runoff water depth to the size of rainfall event, shown in Figure 2, was positively related to field age when considered for all of the fields in the study (Figure 3). The slopes approached a constant value of 0.6 at a field age of 9 years.
Table 1. Physical and chemical soil properties of the chronosequence in Thiougou
Age Depth Silt Silt 20 Sand 50 Sand 250 N Texture Sand Silt Clay ND.A. D.A. Moisture Moisture Moisture Available
to 20 to 50 to 250 to 2mm at at at moisture
PF 2.5 PF 2.5 PF 4.2
(years) (cm) (), (0) (%) () (No.) (USDA) (%) 950. 950 (No.) (g/ml) (%) (N) (%) (%)
0 0-20 7 32 14 37 1 L 51 39 10 6 1.56 11.1 6.9 3.9 7.2
20-40 7 28 13 41 1 LS 55 35 11 6 1.55 10.2 7.4 3.9 6.3
40-60 0 5 1.60 *
1 0-20 8 29 16 38 2 LS 53 37 10 3 1.50 12.1 7.0 4.1 8.0
20-40 7 28 16 38 2 LS 54 35 11 3 1.53 11.2 6.8 3.9 7.3
40-60 9- 24 12 37 1 LS 49 34 17 3 L60 14.9 18.0 6.4 8.5
2 0-20 7 27 19 40 2 L 59 34 7 3 1.44 10.3 4.8 2.6 7.7
20-40 8 25 17 40 2 LS 58 33 9 3 1.45 10.0 5.6 3.4 6.6
40-60 8 23 15 390 2 LS 54 31 15 3 1.57 13.4 7.9 5.4 8.0
4 0-20 9 27 18 39 1 LS 57 36 7 3 1.47 9.9 5.7 3.3 6.6
00 20-40 8 25 16 42 1 LS 58 34 9 3 1.57 11.5 5.8 3.2 8.3
* 40-60 11 23 13 44 1 LS 57 34 9 0 11.7 5.2 3.1 8.6
5 0-20 7 27 19 39 3 LS 58 34 7 _3 1.53 11.8 5.4 3.1 14.5
20-40 8 26 15 41 3 LS 57 34 91 3 1.58 11.3 6.7 3.7 13.8
40-60 9 23 12 38 3 L 50 32 17 0 14.4 8.8 5.7 14.1
7 0-20 10 27 16 39 1 LS 55 37 8 3 1.57 10.5 6.4 4.0 6.5.
20-40 9 25 14 41 1 LS 55 .34 11 3 1.67 11.3 6.5 3.9 7.4
40-60 9 20 10 39 1 L 49 29 23 0 -16.1 10.7 6.9 9.2
9 0-20 8 21 18 46 1 LS 63 29 8 3 1.50 9.0 5.5 2.7 6.3
20-40 9 20 16 45 LS 61 28 11 3 1.56 11.1 7.7 5.3 5.8
40-60 9 18 10 38 LAS 48 27 25 3 1.61 18.3 14.6 9.2 9.1
17- 0-20 8 32 20 31 1 L 51 40 9. 3 1.56 9.9 6.2 3.3 32.5
20-40 11 29 17 31 1 L 48 40 13 3 1.56 13.9 7.6 4.6 28.6
140-60 12 25 15 30 1 1 L 45 37 18 3 1.65 14.9 9.1 6.5 8.5
Table 1 (Cont.)
Age Depth pH water pH KCI Org. C.O. N C/N P total P Ca Mg K Na Bases CEC Sat. Pse
M. total avail. Base
(years) (em) p(molar) p(molar) (.) (%) (%) (-) (mg/kg) (mg/kg) (meq/ (meq/ (meq/ (meq/ (meq/ (meq/ (%)
Sg00 lOg) I Og) O g) O g) b IOg)
0 0-20 6.7 6.3 1.09 0.63 0.37 17 49 3.0 2.03, 0.49 0.15 2.67 3.73 72 *
20-40 5.7 4.8 0.50 0.29 0.17 17 40 0.9 _0.68 0.26 0.02 0.96 1.71 56 *
1 0-20 6.3 6.1 0.80 0.47 0.41 13 60- 2.4 1.98 0.52 0.16 0.07 2.77 3.98 66 1
20-40 5.4 4.9 0.42 0.24 0.21 12 54 1.1 0.98 0.27 0.08 0.07 1.36 2.10 64 -2
40-60 4.9 4.7 0.43 0"25 0.21 12 56 0.9 1.46 0.38 0.07 0.07 1.98 2.51 79 3
2 0-20 6.2 5.8- 0.56 0.32 0.27 12 75 2.0 1.31 0.33 0.14 0.05 1.83 3.36 54 2
20-40 5.3 4.6- 0.38 0.22 0.16 14 57 1.1 0.92 0.29 0.07 0.04 1.30 3.22 41 1
40-60 5.2 4.3 0.23 0.16, 0.12 13 64 0.8 1.14 0.35, 0.10 0.07 1.63 3.52 49 2
4- 0-20 5.8, 5.8 0.86 0.50 0.15 33 63 0.5 1.80 0.51 0.07 0.04 2.42 3.92 62 1
20-40 4.9 4.7 0.43 0.25 0.16 15 49 1.4 1.76 0.36 0.02 0.04 2.18 4.89 45 1
40-60 4.4 4.2 0.22 0.13 0.13 10 64 0.5 0.96 0.30 0.05 0.04 1.34 1.49 90 3
5 0-20 5.7 5.5 0.45 0.26- 0.27 10 66 1.5 1.09 0.32 0.09 0.04 1.52 3.46 44 1
20-40 5.0 4.4 0.40' 0.23 0.18 49 67 0.9 1.18 0.36 0.08 0.04 1.63 3.52 48 1
40-60 4.9 4.4 0.51 0.32 0.17 22 67 0.6 0.91 0.28 0.07 0.05 1.28 3.12 41 2
7 0-20 5.3 5.4 0.64 0.37 0.29 13 60 1.6 1.01 0.39 0.10 0.04 1.53, 1.78 86 2
20-40 4.2 4.1 0.33 0.19 0.17 11 49 0.9 0.98, 0.21 0.05 0.10 1.34 2.67 50 4
40-60 4.0 4.0 0.29 0.17 0.17 10 49 0.3 1.18 0.33 0.07 0.07 1.65 2.92 56 29 0-20 6.4 5.7 0.40 0.23 0.22. 10 71 1.4 1.27 0.32 0.12 0.07 1.78 3.64 49 2
20-40 5.7 4.3 0.40 0.23 0.16 15 71 0.9 0.76 0.30 0.12 0.07 1.24 1.78 70 4
40-60 4.8 3.9 0.62 0.36 0.19 19 85 0.5 0.83 0.19 0.15 0.10 1.27 2.37 54 4
17 0-20 6.4 5.7 0.59 0.34 0.29 12 78 2.3 1.49 0.36- 0.15 0.07 2.07 4.28 48 2
20-40 5.0 5.0 0.40 0.23 0.26 9 64 0.9 1.57 0.45 0.07 0.07 2.14 3.85 55 2
40-60 6.6 5.1 0.71 0.41 0.16 26 71 0.7 01.95 '0.39 0.05 0.04 1.42 3.46 41 1
Figure 4 shows that water infiltration decreased significantly after first cultivation, and total seasonal infiltration was drastically reduced at a field age of 17 years. Soil moisture profiles recorded on several plots during the season (Figure 5) illustrate that surface horizons under fallow were rapidly saturated at the time of the first measurements early in the season. Fields cultivated for a long time, such as the 17-year-old field, only reached saturation toward the end of the season in mid-September. The trend was not clear for fields of intermediate age. Texture and plant extraction differences among fields may account for this.
o' 15""--/hO6 .6
210 ............... ...... .......... E 0
0)~~ ~~ 2Ri3 81 0-~ %14* ~ 8
0 ) 0 ......... ....... .......... ...... ......... ...... .. -----1 5 ... ..
C o 1 0 ...... -............................. ...- . .......... i .............. t ........ i ........... ...
10 ........... ... .... ............. .... .......... ...... 5v v > 2 0 30 -12 11 0 6 o 0.- 12 16
Age of field (years) 0 20 40 60 Age of field (years)
5 Rainfall event (mm) F 3.
Fiue1. The decrease in soil / iue3 h nraeo h
roughness over the season for|*Flo il slope of the runoff/rainfall
fieldsoflvaiousfges.d curve (see Figure 2) with
fild o vriusags.- -- 17-year-old field field age.
Figure 2. Runoff/rainfall per
storm event for fields of ages
0Oand 17 years.
Fallow Newly cleared 1 7-year-old
CD 80 ... .... ............. ..............
808 12 1- 0. 4 a 1
Figure 4. Tdtribuioso infltn si andur ruof for filsoi0n,9cad1 e res f age.
rouhnss ve th saso fr sop ofth runof/ri60l
Soil moisture (g H20/g soil)
3 6 9 12 15 3 6 -9 12 15 Top row:
- 2 0 ...... .... ......................... .., . ....................... . 7 A ug us t
.... 17 Sept.
-4. .. -.......... pF.2.5(F.C.)
- 40 .................. ......... ........ ...... ...... ; ............. ... ... .. ....................4 .. .. ....... .... R 2 5 ( .
.. -@ pF 4.2 (RW.P)
I __ __ __
.. ... ... 7 ..... ... .. ......... f ........................................ : .... ...........t o r w
- 50 ........t ............ ., "." Bottom row:
-.0 -. ',\ Age of field noted on
- 8 0 .. ........... ............... ........ .-..- ... ............. -\ .......................... ............ ... ---...... A
Fallow' field (0 r) 17 years ; graph next to each profile,
E -100 all 17 Sept.
o 0 ",' 0"
- 2 0 ..... ... .... .. .. ................. ...... ... .. . . . . . . . .. ........... . .. ... ...... ....... ................. . . . . . . .
-40 1. '17%.. .
- 4 ....... ......... ......... : - - ..... .. I . ... .... ....
-60... .... . ...X
-.. .....a. ........ ..... \ ..... .
3 6 9 12 15
Figure 5. Moisture profiles for fields of various ages.
The Evolution of Soil Chemical Properties. Organic matter in these soils was generally concentrated in the surface soil. Organic matter content was less than 1% in the surface 20 cm in all fields sampled, except in the fallow field (1.09%). Organic matter content declined exponentially (Figure 6), and at 4 to 5 years of age equaled half of the fallow field's level. Later on, the decline in organic matter content slowed and became somewhat constant at about
Table 1 shows that all field ages under study had a low (<1%) N content. Table 1 also shows that the evolution of nitrogen content was similar in shape to that the organic matter (Figure 6), but the exponential model did not explain as much of the observed variability. (18% versus 53%). All soils studied were low in total P No pattern of total P with field age could be detected (Figure 6). In contrast and more significantly for plant nutrition, soils were generally deficient in available P (Figure 6). In the 0-20 cm layer, from a value of 3 mg/kg in fallow, there was a decrease of 50% in the level of available phosphorus after 4 to 5 years of field age (Figure 6). Thus, the trend of available P with field age was also similar to that for organic matter.
Plots can be grouped in two categories regarding pH, CEC, and exchangeable (Ca, Mg, K, total) bases(Table 1). The first group includes fallow (0 years) and newly cleared fields (1 year). In this group, there was a drastic difference between the 0-20 cm layer and the 20-60 cm layers, which matches the pattern for organic matter. The second group contains all the older
fields of the chronosequence. Bases and CEC, on the other hand, were largely similar between the surface and bottom layers.
The ratio Na: CEC (exchangeable sodium percentage) was an average of 3%. Alkalinity is therefore not a problem.
1 .0 .................................... ....... .......... .................. ...... .
1. ,! R =18%
2 - -". 3 0 .3 5 ............. .............. i.... .................. ............... .... ..
.................... .................. .................. -..... i
co 0 E 0 .3 0 ...... ............ ...... ................
O ~.. ....... ........-- -a ........... ..- ...................... ......... ".... ... a
....... ... . .... .
............ ........... 0 ......2 5.....
0.4 :. ...........
0 4 8 12 16 0 4. 8 12 16
90 -----r T
6 0~......... ..........................................................................
.......... .......... ........................................................
8, :~* 232%1
50 0 9
0 0 . .
0 4 8 12 16 0 4 8 12. 16
Age of field (years)
Figure 6. Change in several chemical properties (organic matter, N, K, and available P).
The Methodology.. Several studies have been undertaken to describe the evolution of soil physical and chemical properties on cultivated, tropical soils. Most were conducted on research stations. Experimental designs were often difficult to execute, complex, multi-annual, and very costly. Unfortunately, this high level of investment did not ensure that conditions and results encountered are those which farmers face. In order to succeed, three challenges had to be addressed in the on-farm research work: environmental variability, study complexity (and
therefore the cost of execution), and duration of the study. In order to reduce environmental variability, a single soil mapping unit (modal leached tropical ferruginous soils) and a single group of cultural practices (farming with animal traction) were considered. In order to minimize design complexity and cost, field devices were designed to consume recycled materials (e.g., old tin sheets, plastic pipes, motor oil barrels). The duration of the study, which would have necessarily been long in order to track individual fields over time, was shortened through the selection of a "chronosequence", or a series of field ages since clearing. Nevertheless, the number of plots was limited by two major constraints. First, researchers had to monitor plot management over a large geographic area Second, observations for a variety of field ages were conducted on the different fields during a single agricultural season, effectively concentrating the workload into this season. Despite these constraints, the data analysis revealed significant trends and results can be compared to those obtained on research stations and those resulting from monitoring of individual plots over time (Nye and Greenland 1960; S~dogo, 1993). Therefore, this approach is well suited to studies of soil degradation and could be employed in other regions.
The Soils. Based on field observation, the soils became progressively sandier as field age increased. Farmers also call soils on the older fields "bisri", meaning sandy. A textural analysis of the 0-5 cm layer probably would have revealed this increase in the percentage of sand, but was not carried out.
The rapid decline of organic matter is consistent with Hien (1990), who found a 60% decrease of organic matter content after 15 years of continuous cultivation in the more humid cottonproducing zone of Burkina Faso. The rate of mineralization is remarkably fast during the weeks after clearing, when 33% of the organic matter is lost. (Soil samples in the fallow 0year-old field were taken at the end of the dry season 10 weeks before sampling of the same and older fields after tillage and planting.) Since part of the fallow was cleared before the first rains to become the one-year-old field, the fallow and the one-year- old field represent a monitoring of the same plot over time. The-organic matter in-the fallow is rapidly mineralized because of a high level of microbiological activity, which results from the combination of moisture from the first rains, high soil temperatures (averaging 28*C), relatively coarse soil textures, and the use of animal traction to mix and aerate the soil to 8 to 12 cm of depth. This is consistent with S~dogo's (1993) statement that management of sandy soils with no or low organic amendment eliminates the soil's pool of organic matter through mineralization.
Nitrogen levels are comparable to those reported by S~dogo (1989), Sohoro (1992), and Bambara (1993). Table 1 shows that N content in the 0-20 soil layer in the fallow (0-year-old) and new (1-year-old) fields is twice that of the 20-40 cm layer. After two years of cultivation, this ratio declines to about 1. The same observation is valid for the organic matter content, the principal source of N in these soils. Thus, rapid mineralization of organic matter in the 0-20 cm layer after land clearing is concurrent with rapid N loss. This N is either leached, volatilized as ammonia, denitrified, or taken up by crops and weeds. Since N is not typically added in organic or mineral form, this loss continues each year.
The trend for available P is very similar. The ratios of available P in the 0-20 cm layer to available P in the 20-40 cm layer are 3.3, 2.2, 1.7 for the fallow, 1-year-old and 4-year-old
plots respectively (Table 1). The presence and decay of available P inl the surface 20 cmn is therefore also correlated with organic matter content. After organic matter is mineralized, available P content in surface layers approaches levels of available P in deeper layers, where organic matter, N, and available P are low regardless of field age.
Similar comments can be made for pH, CEC, and exchangeable bases. The high correlation between these factors and organic matter can be explained by the high percentage of CEC on the organic matter in these soils (Jones and Wild, 1975).
Organic matter plays an important role in the soil is structural stability. The relatively high level of 'organic matter in years 0 and 1, possibly including dead roots and soil flora and fauna, probably stabilizes structure, maintaining a more constant soil-roughness. Consequently, the decline in soil roughness over the season for young fields Was less significant. On older plots, the degradation of plant and microbial, biomass and lower levels of organic matter affect soil structural stability. Any sort of roughness created by tillage cannot withstand substantial raindrop impact. This is why initial soil roughness in fields cultivated for over 4 years decreases by 15% during the agricultural season. The causal relationship between soil roughness and runoff, whereby soil roughness slows water runoff, is well established (Stallings, 1957). Soil roughness -also allows for more, infiltration of rainwater, which is then available to plants. The rapid smoothing of older fields, therefore, leads to more runoff and less infiltration.
To summarize, the change in organic matter content governs the evolutionary trend of soil chemical and physical characteristics, at least in the 0-20 cm layer. The trend is negative, that is, it corresponds to a rapid decline in fertility of leached tropical soils. In a span of 10 years of cultivation, the land is no longer productive. Beyond this time, cereal production and farmers' livelihoods are jeopardized. Taonda et al. (1995) show that sorghum ~productivity on these soils, which was 1300 kg/ha on newly cleared plots, -declines to 250 kg/ha in 5 to 6 years,, amounting to an 80% decrease.
Migrants have settled in the frontier zone in search of land with fertile soil, only to find fragile soils. The vicious cycle of immigration, continuous cultivation, land degradation and, emigration repeats itself in the frontier zone. Should this process continue at its current pace, the whole region of the southern part of th 'e Central Plateau may lose much of its agricultural production potential. This would be disastrous, considering the fundamental role this region plays in the nation's food supply. It is therefore imperative to sto Ip or even reverse this degradation.
Any successful soil restoration technology for older fields must'include a combination of improved organic matter management and erosion control practices. Indigenous farmers, aware of the potential for degradation, have begun fertilizing village fields with various local organic amendments, such as household refuse, farmyard manure, or compost. 'In addition, they have constructed several types of erosion control structures in village fields, such as earth dikes, rock bunds, and vegetated strips, the latter being the least costly and perhaps the most suited to the frontier regions. Bush fields, on the other. hand, are cultivated without the benefit of either organic amendments or erosion control structures. However, Taonda et al. (1995) showed that the application of a low rate of farmyard manure (2.5 t/ha) on a bush field protected by erosion
control structures increased the productivity of the 17-year- old plot (from this study). It rose from 13% to about 70% of the sorghum productivity (1300 kg/ha) obtained on 1- and 2-yearold plots.
Several constraints restrict restoration of degraded soils. First, individual farmers have to produce a sufficient quantity of organic amendment. This, in turn, requires labor, farm animals, and an integration of livestock and crop production. Second, there are many thousands of hectares of bush fields. The treatment of whole watersheds with erosion control measures cannot be achieved at the level of individual farm families. Therefore, construction of such structures should be handled by whole village communities.
Bambara, D. 1993. Dynamique de la matibre organique selon les systhmes de culture dans les
sols agricoles du finage de Thiougou: Approche quantitative. M6moire de Fin d'Etudes
IDR. 100 pages + appendices.
Dickman, S.R., and R.H. Bray. 1941. Replacement of adsorbed phosphate from kaolinite by
fluoride. Soil Sci. 52: 263-273.
Jackson, M.L. 1958. Soil Chemical Analysis. Prentice-Hall, Inc., Englewood Cliffs, N.J. Jones, M.J. and A. Wild. 1975. Soils of the West African Savanna. Commonwealth Agricultural
Bureau Technical Communication No.55. Farnham Royal, Slough, England. Milleville, 1988
Nye, P.H. and D.J. Greenland. 1960. The Soil Under ShiftingCultivation. Commonwealth
Agricultural Bureau Technical Communication No.51. Farnham Royal, Slough, England. Olsen, S.R. and L.A. Dean. 1965. Phosphorus. In: Methods of Soil Analysis, Part 2: Chemical
and Microbiological Properties. American Society of Agronomy. Madison, WI. pp. 10351049.
Playsier. 1978. Personal communication.
S6dogo, M. 1993.
Siband, P.1972. Etude de l'6volution des sols sous culture traditionnelle en Haute-Casamance.
Principaux r6sultats. Agron. Trop. 27(5): 574-591.
Stallings, J.H. 1957. Soil Conservation. Prentice-Hall, Inc., Englewood Cliffs, N.J. p.51. Taonda, S.J.B., J.B. Dickey, and P. S6dogo and K. Sanon. 1995. Characterization of the soilplant system in bush fields in the tropical North Sudanian region of Burkina Faso. Part II:
Evolution of field productivity on continuously cultivated soils. In manuscript.
Walkley, A., and I. Black. 1934. An examination of the Degtjareff method for determining soil
organic matter and a proposed modification of the chromic acid titration method. Soil
US Dept. of Agriculture, Soil Conservation Service, Soil Survey Staff. 1975. Soil Taxonomy: A Basic System of Soil Classification for Making and Interpreting Soil
Surveys. Agricultural Handbook No. 436.
Economics of Rock Bunds, Mulching and Zai in the Northern Central Plateau of Burkina Faso, A Preliminary Perspective
D. Kaborb, F. Kambou, J. Dickey, and J. Lowenberg-DeBoer
In response to national policy and farmer requests, the Farming Systems Program (RSP) of the Institute of Agricultural Research and Studies (INERA) of Burkina Faso is conducting research on soil conservation and fertility restoration techniques. Soil erosion, compaction, crusting and declining fertility are common problems in the Central Plateau of Burkina Faso. These soil problems are particularly acute at the Donsin RSP site in the province of Namentanga, about 103 km northeast of Ouagadougou (but 230 km by road). Rock bunds, za'i and mulching are being tested. The objective of this report is to provide a preliminary perspective on the cost of implementing these techniques and on yield effects. The data presented here are necessarily incomplete, but it is hoped that they will help guide future research.
Rock bunds (cordons pierreux) are low rock walls that are laid on the contour. The purpose of these bunds is to slow runoff, increase infiltration and reduce soil erosion. Rock bunds are a proven technology and have been constructed in many parts of the central plateau. They are included in this analysis for the benefit of comparison.
Mulching is a traditional soil conservation and fertility restoration technique in the central plateau. During the dry season grass cut from uncultivated lands is spread on crop land that suffers from slow water infiltration and consequently from drought. When rains start, the mulch reduces runoff and helps hold soil moisture. Termites colonize the mulch and soil beneath it, increasing porosity and speeding decomposition. Decomposition of the grass adds to soil fertility.
ZaYi is an intensive manure management and water conservation technique. During the dry season a shallow hole is dug for each hill of sorghum or millet that will be planted when rains start. Each hole is partially filed with manure or compost which is less prone to crusting and compaction than soil. The holes trap rain water and reduce runoff. The organic matter helps retain moisture and has a "starter fertilizer" effect on plant growth. Za'Y has long been practiced in Yatenga, but is a new technique at Donsin. The primary purpose of this report is to compare the economics of za'i to the better known techniques of building rock bunds and mulching.
The data collection methodology is presented in section 2, a presentation of the data and results in section 3, discussion in section 4 and researchable issues in section 5.
Primary data was collected in interviews with farmers who use the techniques under study. This interview data was supplemented by information from the Soil Management and Resource 67
Conservation Project for the Central Plateau (PATECORE), the Soil and Water Conservation and Agroforestry Project (CES/AGF) and Foster Parents Plan (PPI).
The farmer interviews were conducted on Sept. 10 and 11, 1993, at Donsin. The interview team was composed of Daniel Kabore, Economist and Coordinator of the RSP central team, John Dickey, agronomist on the Agricultural Research and Training Support (ARTS) project technical assistance team, Salif Boena, RSP technician at Donsin, and J. Lowenberg-DeBoer, economist and ARTS campus coordinator. The interviews were conducted in Moor6, with translation by Boena into French for the benefit of Lowenberg-DeBoer. The interviews were free form. No questionnaire was used because the initial information was inadequate to formulate appropriate questions.
Three farmers provided most of the information, but 5 other farmers added certain details. These three farmers were chosen because they employ at least two of the practices studied and because they cooperated with RSP at Donsin. In addition to the interview, planting density was measured in the fields of each farmer.
The information from PATECORE was supplied primarily by Robert Delma, head of the Development and Follow-up Unit, in an interview on Sept. 14, 1993, at the headquarters in Kongoussi. Frederic Kambou, researcher in the INERA fertilization, soil, water and mechanization program (ESFIMA), and Lowenberg-DeBoer participated in this discussion. In addition, PATECORE reports for the years 88 to 92 were consulted. PATECORE is a German financed project. It does not participate in bund construction directly, but offers technical and material assistance to government agencies (primarily the Regional Centers forAgricultural Production (CRPA)) and non- governmental organizations (NGO).
The information from CES/AGF was supplied by Gouyahali Son, project coordinator in INERA/ESFIMA on Sept. 16, 1993, at the research station at Kamboins6. Kambou and Lowenberg-DeBoer participated in this discussion. The International Fund for Agricultural Development (FIDA) finances CES/AGF.
The information from PPI was supplied by their agent at Donsin. In addition, the Sanou and Ouedraogo report on soil management at Donsin was consulted.
III. RESULTS AND DISCUSSION
Rock Bund Background Many techniques for the construction of rock bunds have been developed in Burkina Faso. They differ in the way contours are laid, preparation of the soil where the bunds are to be built, the arrangement of the stones and management of construction labor. Three basic types outlined by Son are:
I) The three stone system also called the FEER system for the Rural Water and Equipment Fund (FEER) which did much of the development of this system. In its classic form the FEER system had 6 steps:
1) Tracing of contours by a topographical team composed of 3 persons using surveying
2) One pass by a tractor and disk plow with soil thrown up slope.
3) Collection of stones by farmers in piles of about one truck load, roughly four cubic meters.
Tools used are pick, digging bar and wheel barrow.
4) Stones are manually loaded onil trucks by farmers, hauled to the construction site and
5) Farmers lay the stones on the contour in two layers. On the soil surface two parallel rows
are laid next to each other. A single row of stones is laid in the second layer overlapping
the middle half of each first layer stone. A cross section of the bund would show three
stones (Figure 1).
Cross section c
Figure 1. Top and cross section views of a rock bund built according to the three stone system.
6) Upslope from the bund farmers pile soil loosened by the plow against the foot of the bund.
This procedure has been modified by some organizations, in particular NGOs, to reduce costs. NGOs often use water levels made of clear, flexible plastic hose with 2m at each end attached to graduated poles to trace the contours. They train a few farmers per villages to use the levels. These farmers then help their neighbors trace contours. This eliminates the use of trained surveyors and their travel costs. In addition, the NGOs often eliminate the preparation of soil where the bund is to be built and manually earthing-up the upslope side of the bund.
According to Son the disadvantages of the three stone system are:
1) large holes between the stones allow a substantial flow of water between the stones, thus
permitting some soil to be transported beyond the bund.
2) ifthe stones are badly aligned, channels can be created that turn into ravines. 3) soil deposits between the two rows of stones can reduce infiltration and thus cause flooding
upslope from the bund.
Soil conservation efforts in Burkina Faso have largely switched from earth bunds to rock bunds. Initial work in the late 1970s focused on earth bunds. The soils ofthe Central Plateau often have slow rates of water infiltration. Thus water was retained behind the bunds and crops upslope were flooded. In some cases, farmers intentionally opened the bunds to save their crops from flooding. In other cases the water overtopped the bunds. In either case gullies were
created. Properly constructed rock bunds allow water to pass, but in a diffuse manner which does not create gullies.
Earth bunds are still used in some areas where stone is not available within a reasonable hauling distance (about 15 km) to the fields. In those cases, there is an effort to include a section of rock every 30 to 50 meters, to allow filtration.
I1) Erect stoneswith subsoiling (PDS) This system was developed by CES/AGF in response to problems identified with the three stone system. The procedure follows 6 steps:
1) Tracing of contours by a topographical team composed of 3 persons using surveying
2) Two passes by a tractor and two shank subsoiler. Three furrows are created because one
subsoiler shank passes through the middle furrow twice.
3) Collection of stones by farmers in piles of about one truck load, about 4 cubic meters. Tools
used are picks, digging bars and wheel barrows.
4) Stones are hand loaded on trucks by farmers, hauled to the construction site and dumped.
5) Stones are laid by farmers. Large stones are set upright in the middle furrow with the
smallest end down and the flattest side upslope. Small stones are fitted between the erect
stones from the upslope side so that water forces the small stones into the gaps between the upright stones. If the small stones were placed below the erect stones, water would tend to
scatter them. Downslope of the erect stones, large stones are laid flat at the foot of the bund
to help hold the stones erect (Figure 2).
Figure 2. Top and cross section views of a rock bund build according to the PDS system.
According to Son, advantages of the PDS method include permeability maintained over a longer period, improved establishment of wild grasses and lower stone requirement. The classic three stone method requires 20 to 22 cubic meters of stone per hectare. The PDS method requires about 12 cubic meters per hectare. This is important because wide spread installation of rock bunds is exhausting stone supplies close to cultivated areas. According to Son, hauling distances were commonly 5 to 7 km. for the CES/AGF in 1989.
IV) Aligned stones The simplest rock bund system consists of large stones aligned along the contour (Figure 3). Small stones are often placed on the upslope in the gaps between the large stones.
Figure 3. Top view of a rock bond built according to the aligned stones system.
Of the three systems outlined, the aligned stones bund requires the least stone, but it also allows the greatest runoff. Stones are vulnerable to being dislodged by water or animal traffic.
Any of the rock bund systems can be built by community or individual action. Burkinab6 government agencies tend to favor community action. The CES/AGF and the CRPAs usually work with communities to protect a designated slope or watershed. Relatively large groups of village residents are mobilized on designated work days.
The government approach may include protection of bushlands upslope from fields. According to Son, the benefits of anti-erosion work in upslope bushlands include protection of lower toposequence structures and pasturage improvement. Heavy runoff from unprotected upper toposequence areas can overwhelm lower slope bunds. In addition, improved water infiltration in the bushlands provides moisture for plant growth and can help replenish ground water.
Many NGOs work with individual farmers to control erosion on their fields. They often concentrate on lower toposequence (and thus more productive) fields.
Rock bund labor times Labor times were collected for bund construction by an individual farmer at Donsin and for PATECORE community work during the 1993 season (Tables 1 and 2). It should be noted that these times relate to specific construction approaches. Labor times for other systems may differ. The Donsin farmer used a modified three stone system without preparation of the soil. Most PATECORE sites use a modified three stone system without soil preparation, but a few use the PDS method.
Table 1. Donsin Farmer Labor Times for Construction of Rock Bunds, hr/ha. Item Men Women Children Total
Gathering stones *25 25
Hauling stones 18 18
Tracing contours 4 4
Laying stones 13 38 50
Total labor 60 38 ,_ 97
Table 2. PATECORE Labor Times for Construction of Rock Bunds, hr/ha. Item Men Women Children Total
Gathering stones 70 56, 47 173
Loading trucks 70 56 47 173
Tracing contours 8 8
Laying stones 130 104 86 320
Total labor 278 216 180 673
According to Delma, the average PATECORE bund density is 500 m/ha, which translates to bunds spaced about 20 m apart. At the time of the writing of this report the bund density for the Donsin farmer was not available. The farmer labor times assume the 500 m/ha.
Rock bund construction on a large scale is a relatively new development in Donsin, thus rock is available relatively close to fields. The farmer in Table 1 benefited from the availability of stone next to his field. Some stone was broken with a digging bar. He hauled the stone with a borrowed wheelbarrow.
The family labor available in the farmer's case was three men and six women. Men gathered and hauled stones. The women helped in laying the stones. The work was done during the hot season. Because of the heat, the usual work day was from 6 a.m. to about 9 or 10 a.m. Thus the 60 hours of work by the three men represents about one week of activity.
The farmer received the help of a PPI trained neighbor in tracing the contours. A mason's level supplied by PPI was used.
The PATECORE community work (Table 2) was usually in about 7 hour days. According to Delma, a typical workday would start at 8 a.m. and continue until 4 or 5 p.m., with a break a midday. Their construction season starts in October and continues until the rains come (usually in June), but because of the heat and fasting during Ramadan, it becomes increasingly difficult to organize workdays after January. The seven hour workday is important for efficiency in use of the truck and project personnel time.
According to Delma, the average workforce composition in 1993 was 30 men, 24 women and 20 children. Women helped in all activities except tracing the contours. The work time of truck drivers and project personnel are not included in Table 2.
The labor times estimated by Sanou and Ouedraogo for PPI activities at Donsin are intermediate between the farmer times and PATECORE averages. Their total is about 432 hr/ha (assuming 8 hour workdays), with 240 hr/ha for gathering stones, 96 hr/ha for laying out the contours and 96 hr/ha for laying the stones. The PPI activities at Donsin are concentrated on individual farmer fields, but some coordination at the community level is needed to insure efficient use of the truck. The truck is sent to the village only if a sufficient amount of stone has been collected for a day's hauling.
The value of labor used for rock bund construction depends on other labor opportunities available. Because construction occurs in the dry season, agricultural labor rates are not relevant. Dry season wage labor is rare in rural areas and almost nonexistent for women and children. Study of nonagricultural activities at Donsin (Lowenberg-DeBoer, 1993) suggests that the opportunity cost of labor is 50 FCFA/hr or less during the dry season. At 50 FCFA/hr the opportunity cost of labor for the work time estimates are: the farmer in Table 1, 4,850 FCFA/ha; PPI labor times estimated by Sanou and Ouedrago, 21,600 FCFA/ha; and PATECORE average labor times, 33,650 FCFA/ha.
Labor time Differences A comparison of Tables 1 and 2 indicates that PATECORE labor times are substantially higher than those of the Donsin farmer. There are several hypotheses which might explain the labor time difference:
1) The amount of stone used by the farmer was less than the 20 to 22 cubic meters/ha used by
2) The individual farm family was more motivated than the workers mobilized in a community
workday. The farm family benefits directly if their soil is improved. The community work
benefits some people only indirectly.
3) Because the farmer did not use a truck, he was able to concentrate the heavy work of
gathering, moving and laying rock in the relatively cool mornings.
It is hypothesized that the labor times collected by Sanou and Ouedraogo are intermediate between the two other cases because individual fields were being protected, but truck use efficiency forced some changes in the work schedule. The key changes are a latter starting time and work in the afternoons. Because of travel time to the work site, work days for truck hauling start about 8:00 a.m. Farmers often start work at dawn (about 6:00 a.m.). Efficiency in truck use requires work to continue into the afternoons in spite of the heat.
Hauling Cost The truck use costs reported by PPI and PATECORE (Table 3) are comparable. Both projects rent trucks. According to Delma, PATECORE also has some of its own trucks, but finds rental less expensive. Diesel fuel cost is 245 FCFA/1.
Table 3. Truck Cost for PATECORE and PPI. Item PATECORE PPI
Area treated perday,ha 2.5 2.5 ,
Rental, FCFA/day 27500 27500
Fuel, FCFAlday 18865 19600
Cost per day, FCFA 46365 47100
Cost per hectare, FCFA 18546 18840
The importance of using trucks for full days can be seen in comparing per hectare hauling cost for full days (2.5 ha/day) and half days (1.25 ha/day). For example, the PATECORE hauling
cost per hectare rises from 18,546 FCFA/day to 32,976 FCFA with half day work, a 78% increase. Fuel cost are reduced by half day work, but travel to and from the work site is unchanged.
Rock hauling with animal or human powered carts has been tried with limited success. The volume of rock that can be hauled in a cart is small and hauling time is long for the 5 to 10 km distances often involved.
Rock Bund Subsidy Most rock bund construction in Burkina Faso is subsidized by donors. The case of the farmer in Table 1 is unsubsidized, except for the water level and the PPI training of the neighbor in tracing contours. The farmer's case is useful as a pure case of estimating labor times, but it is relatively rare because stone is usually not available close to fields.
Hauling costs are an important part of the subsidy. The PATECORE and PPI data indicate that this subsidy is about 19,000 FCFA/ha.
Other subsidies come in the form of project personnel time and small equipment. PATECORE provides about 200,000 FCFA per village in the form of small tools: shovels, picks, digging bars, wheel barrows. The bund construction systems which use soil preparation on the bund construction site have another subsidized element. Many of the projects involved in rock'bund construction are multifaceted. Separation of rock bund costs from other activities is not easy.
Mulching Most farmers at Donsin mulch at least a small area of cereal crops with grass collected from uncultivated fields. Mature grass is collected in the dry season with a rake. In most cases, a sickle is not used to cut the grass because it requires bending over in the dust raised by the cutting. Use of a rake allows the individual to stand erect and above much of the dust. The rake breaks the brittle grass stems, leaving the root crowns in place.
The grass is collected in bundles and transported to the field. The farmers all mentioned the competition for grass close to the fields. Early in the dry season farmers collect the grass in bundles, leaving the bundles in the bush for later transport. Collecting the grass in bundles establishes an individual's claim to the grass. Later in the season bundles are collected and transported in a single activity.
Near the end of the dry season, farmers walk up to 2 hours from the village to find mulch grass. Farmers state that their interest in zal is partially due to the fact that mulch sources have been exhausted.
The experience of Farmer 2 (Table 4) suggests that availability of a cart can substantially reduce labor times, though interpretation needs to be made with care because of differences in coverage per bundle.
The density of mulch application appears to vary from farmer to farmer (Table 4). Because the interviews took place in the rainy season it was not possible to weigh bundles. Bundle size may be a factor in the coverage area differences. Farmer 2 uses two coverage rates, one for average soils and one for small depressions and other more humid spots. For average soils the mulch application rate varies from 15 to 44 m2 per bundle (Table 4). The rate for humid soils is much lower, one bundle covering 77 m2.
Table 4. Mulching Experience at Donsin, 1993. Item Farmer 1 Farmer 2 Farmer 3
Density, hill/ha 30769 37104 26667
Area per bundle, m sq 15 44 30
Mulch, bundles/ha 686 227 333
Transport Carry Cart Carry
by bundle 12 bundles by bundle
Max Walking Time, min. 120 120 4*
Dry season labor time
Gather mulch, hr/ha 69 166 56
Transport, hr/ha 412 Combined Combined
Distribution, hr/ha 137 35** 37
Dry season total 618 201 93
Rainy season labor time relative to unmulched, flat planting Planting x2 x3 x3
1st Weeding x3 x5 x3
2nd Weeding ? x2
Expected yield effect x2 ? xl.75
relative to unmulched,
flat planting _, _,_
* Estimated based on farmer statement that mulch was cut close to field and by subtracting the gathering time of other respondents from total time given.
** Fannrmer unable to quantify time. Average time per bundle of other respondents used to complete labor estimate.
Planting density in mnulch appears to be the same as in unmulched crops (non-za'i), planting time is increased because mulch must be moved aside to make the holes for planting. Farmers commented that all mulch must be kept from the planting hole to avoid termite damage to seed.
First weeding work time is from 3 to 5 times higher in mulched than in unmulched fields because mulch must be moved aside to hoe the soil. Second weeding work time is also increased.
Farmers expect yields on mulched soil to be approximately double those on unmulched fields.
Za'i Many farmers in Donsin used the zai technique for the first time during the 1993 rainy season. Some farmers had seen za on a trip to Yatenga organized by RSP. Many of them had seen the single field of zai in their area in 1992, near Bonem (about 15 kmin).
The willingness to try zai should be seen in the context of rapidly declining soil productivity at Donsin. The most extreme examples of erosion are found on the zipel6, barren areas of baked
subsoil on which even the hardiest plants have trouble gaining a foothold. Based on aerial photos, Sanou and Ouedraogo (1993) estimate that between 1990 and 1992, the zipel6 area at Donsin grew by 1% annually.
But declining soil productivity by itself is not enough to convince farmers to adopt a new practice. For example, farmers in the Donsin area have not adopted chemical fertilizers and tied ridges, though these practices have been shown to improve yields. The innovations must use available land, labor and capital more efficiently than alternative practices.
PATECORE has tried since 1990 to introduce zai as an accompanying practice in fields protected by rock bunds. Relatively few farmers have adopted the practice in the areas where PATECORE works. Delmar indicated that the low adoption rate could be linked to the level of extension effort. Another hypothesis is that farmers are not convinced that zai is a good use of their limited resources.
Zai production practices varied from farmer to farmer (Table 5). Farmers reported trying several variations of za'i, consciously experimenting in an effort to find the right technique for Table 5. Zai Experience at Donsin, 1993.
Item Farmer 1 Farmer 2 Farmer 3
Density regular, hill/ha 30769 37104 26667
Density za'i hills/ha 25641 23050 31888
Manure per hole, kg 0.6 0.6 0.6
Manure perha, kg 15385 13830 19133
Transport Type Bicycle Donkey Cart Bicycle
Dry season labor time
Dig holes, hr/ha 206 162* 191
Transport Manure, hr/ha 1923 869 3587
Distribute manure, hr/ha 427, Combined 266
Dry season total 2556 1031 4044
Rainy season labor time relative to unmulched, flat planting Planting slower faster slower
1 st Weeding faster ,x3 x4
2nd Weeding faster xO.66
ZaY seed placement in soil in manure in soil
Zal reseeding relative to non- reduced, none less than
zal if planted in zai non-zai
Expected yield effect with x2 no effect x3
manure broadcast relative to
unmulched, flat planting __- _ Farmer unable to quantify time. Figure based on average time per hill of other respondents.
their situation. The variations included differences in hole size and shape, the amount and type of manure, density and seed placement. The variations were based on information that they had gathered in Yatenga, what they had seen in the field near Bolza and their understanding of soil-plant relationships.
Holes for zai may be round or rectangular. Farmer 1 dug holes that were roughly the shape of an inverted cone about 25 cm in diameter at the surface and 10 cm deep in the center. Dirt from the hole was place just down slope from the hole. Farmer 3 used a similar technique, but with slightly larger holes, about 36 cm in diameter. Farmer 2 used a roughly wedge shaped, hole, about 17 cm long across the slope, 20 cm in the down slope direction and nine cm deep along the down slope edge. Farmer 2 piled the dirt from the holes in the space between two row of holes to form a low earth bund (Figure 4): dirt piled between
Figure 4. Top view of zai arrangement used by farmer 2.
Factors in the choice of hole size and shape seem to be the effort required to dig it and the ability of the hole to trap rain water.
All the farmers interviewed said that they thought a double handful of manure (about 0.6 kg) per hole was best. Farmer 3 had run short of manure and had used a single handful in some zai. Farmer 2 had intentionally left some holes without manure to determine the relative impacts of the soil preparation and the organic matter. At the time of the interview sorghum planted by Farmer 2 in zaif was uniformly about 3 m tall and forming grain. Sorghum planted in zai holes without manure was about 1.5 m tall, somewhat uneven and only beginning to flower. In the flat planted fields sorghum was highly uneven, with the tallest plants about 1.5 m and flowering.
Estimates of total manure use ranged from 14,000 to 19,000 kg/ha. Mark Powell, International Livestock Center for Africa (ILCA), has conducted research on manure production by corralled livestock grazing bush and crop residue in Niger. He estimates that the average daily production of fecal dry matter per animal is: cattle, 1.28 kg; sheep, 0.37 kg; and goats, 0.2 kg (Personal communication). Using Powell's estimates, the midpoint application of 16,500 kg/ha would represent the full year's production (365 days) for 35 cattle, 122 sheep or 226 goats. Few farms at Donsin would have enough livestock to do zai on one hectare with pure manure. These estimates suggest that lack of manure would limit the zai area per farm to less than one hectare, unless ways are discovered to increase manure supply or extend it by using other organic matter sources. for example by composting.
Farmer 2 had a compost pit (4mx2mxlm) near his compound. He said that it required about 56 hours to dig. He composted livestock manure, wild grass (like that used for mulch), compound sweepings and wood ashes. Keeping the compost pit moist requires a major commitment of labor. He said that pumping and hauling twelve 50 liter containers each day required about 3
hours per day (1 hour by three men using a donkey cart) from January to May. Farmer 2 had learned about composting during a visit to Zoundweogo Province organized by RSP.
Plant density measured in the fields showed that farmers 1 and 2 reduced plant population in zal. Farmer 3 increased population slightly. The amount of labor per zai hole is probably about constant, thus one way to reduce per hectare labor requirements is to reduce density.
Farmer opinion was divided on the best seed placement. Farmers 1 and 3 hoed through the manure to plant the seed in the soil. The seed was covered with a mixture of soil and manure. They said that seed planted in the manure was subject to insect damage. Farmer 2 planted directly in the manure. He said that soil covering the seed tended to crust and to interfere with emergence.
In general, farmers said that seedling survival was improved by zai. In the 1993 season, many flat planted fields were replanted 3 times. Given theshort growing season, reseeding has a major impact on yield potential. Second and third plantings are often not sufficiently mature at the end of the rains to make grain. Za'i appears to reduce the need for reseeding and to have major implications for yield distributions, and hence the risk characteristics of the cropping system.
Za' requires large amounts of dry season labor. Estimates based on the interviews range from 1000 to 4000 hours per hectare. Digging requires substantial labor, but transporting manure is the major element in the labor time. Farmer 2 was able to reduce his labor time by using a donkey cart and because the corral from which the manure was hauled was near the field. Manure transported by bicycle is put in a sack.
Farmers are divided on the impact of zai on planting time. Part of the disagreement may be related to the lack of experience with the new technique. Two of the three respondents said that planting in za'i as slower. Farmer 1 said that in zaI he could only plant one row at a time, compared to 3 rows in flat planting. Farmer 2 said that planting in zai-was easier because the soil was already prepared.
They all said that the first weeding in zai required extra time, mainly because weeds grew vigorously in the zai hole and had to pulled out by hand for fear of damaging the young sorghum plants. The second weeding was faster in zai because the sorghum grew quickly and dominated weeds.
Because this is the first year of za'i in the village, the farmers were not able to provide yield estimates. Their estimates of yield effects of manure broadcast on flat planted fields vary from no effect to 3 times as high as yields from unmanured fields. Farmer 2 remarked that heavy rains often washed away manure spread on flat planted fields.
Zai also has potential as a soil reclaimation technique for zipel6 (denuded lands). RSP had a demonstration plot in the center of a zipel6 area. Only a few farmers have used zat on zipel6 and then only next to existing fields to reduce damage from wandering livestock. Most Donsin farmers have applied za'f to improve productivity on existing fields.
The economic reasons for farmer interest in zal as a soil management technique at Donsin are related to:
1) higher yields with Zai.
2) potential for risk reduction zai appears to favor early establishment and reduce the need to
repeatedly reseed crops.
3) low capital investment in general there is no initial cash outlay. Tools already available
on the farm can be used initially. Experience on Yatenga indicates that farmers eventually
invest on sturdier pick axes for digging.
4) most of the labor occurs in the dry season alternative labor opportunities in the area are
scarce during this period.
Farmers are interested in za'i for many of the same reasons that they have already adopted mulching. They say that they would expand mulch area if mulch materials were available. Two hours walking distance is about the practical limit of mulch collection. Beyond that travel times become too long. They recognize that zai and mulching could be complementary practices. Farmer 2 planted a small area of combined mulch and zal. But making the most of limited mulch and manure will probably force farmers to apply either one or the other on a given area.
Rock bunds, mulching and zai are complementary practices. Bunds are somewhat effective in keeping soil in place and increasing infiltration, but without accompanying improvements in soil fertility and physical properties, the impact on yield is limited about 10% to 30%. Combination of these practices can increase yields by up to 300%.
Rock for bund construction is becoming a scarce resource. The use of trucks has increased the practical hauling distance for rock, but it appears to force some inefficiencies in the use of labor. Other strategies for increasing the supply of usable rock include the use of explosives.
ZaY has a much more immediate effect on yields than rock bund construction. The main effect of rock bund construction in the first year is reducing rainfall runoff and increased infiltration. Yield effects from the build up of sediment behind the bund show up in the second or third year. Zai also has a carry over effect. The manure does not decompose entirely the first year and crop residues produced in the first year can act as mulch if left on the field. Soil physical and chemical properties may be improved for several years after application. Farmers will probably rotate zal over their fields.
Rock bunds have a long, but probably limited useful life. Their ability to hold soil and water may be reduced if sediment deposits behind the bunds build up near the level of the top of the bund though the terrace thus farmed is less erodible than the original slope. Clay deposits between the rocks on some types of bunds (Three stone system) may reduce water filtration
through the bund and create flooding. The growth of grasses and trees along the bund may turn it into a vegetative strip and effectively lengthen its useful life.
Both zaY and the construction of rock bunds use large amounts of dry season labor. The farmer may be faced with a difficult choice between the two techniques. In general, the labor requirement of bund construction is-relatively low compared to zai. But because zai benefits are more immediate, they may be much more important to the farmer. However, the possibility of covering relatively more area with rock bunds given the same labor may continue to make bunds an attractive investment.
At 50 FCFA/hr, the midpoint value of dry season labor time for zal, the required 2500 hr/ha, is valued at 125,000 FCFA/ha. A crucial parameter in the decision to use zai is the opportunity cost of labor. A farmer who could earn 50 FCFA/hr in another dry season activity may be hard pressed to justify zai. At a harvest time price of 50 FCFAikg of grain, a yield increase of 2.5 metric tons per hectare would be required to breakeven. In addition, dry season earnings from commerce or artisanal activities would probably be less risky and provide a more even cashflow than zaY. Therefore, to the extent that other renumerative activities are available, they may be preferred, but zai offers a potentially profitable use of surplus labor.
Constraints The primary constraints to zaY use are the supply organic material and labor. The manure available on most Donsin farms would be enough for only a fraction of a hectare of zai. There is already evidence of a limiting supply. Farmer 2 said that several people have already asked for a sack of manure. He commented that before the 1994 crop season people will start to steal manure. Farmers commented that they were beginning to manage their animals to increase the amount of recovered manure. For instance, animals were being tethered at night during the dry season, instead of being allowed to roam at will.
Use of compost may help increase the organic matter supply for zai. All types of organic materials can be composted, including crop residues. The evidence gathered here suggests that water hauling is a major constraint to use of compost pits in the Donsin area.
The increased value of manure in zai may have wide ranging effects on the whole farming system. Livestock production, especially small ruminants, is awell developed enterprise in the Donsin area. Many of the Donsin animals supply the Ouagadougou market. Increasing the value of manure may make livestock production more profitable. But more ruminant livestock means more forage. RSP tried dual purpose (grain/forage) cowpeas in Donsin in 1992, but farmers favored varieties bred for grain. If za'i can stabilize cereal yields and increase the profitability of livestock production, the forage question may have to be reconsidered.
In Yatenga, where there is a longer history of za'i, manure has been extended in some cases by reducing the amount per hole and adding a small amount of commercial fertilizer. This retains the physical benefits of organic matter application (for instance in improving water holding capacity and reduced crusting around the young plant), but allows part of plant nutrition function to be taken over by mineral based products. The disadvantage of commercial fertilizer is the capital required for purchasing the product.
The combination of manure (or compost) and rock phosphate has some advantages. The acid in the manure increases the solubility of the phosphate. In the manure mix, the dustiness and handling problems associated with rock phosphate are reduced. As with commercial fertilizer, the capital required for rock phosphate purchase is a constraint.
For farms without animal traction and a cart, labor may be more limiting than manure in some cases. If zai work is done during the period from January to May period, 6 days per week, with a work day of 6 to 10 a.m. because of the heat, the total work time per person is 512 hrs. The farmers interviewed said that most of the zal Work was done by men. Women and children helped mainly in distribution the manure to the zai holes. If women and children did all of the manure distribution, a farm with one man and no cart could have from 0.14 to 0.25 hectare of zaI (using labor times from farmers 1 and 3). In a similar circumstance, a farm with a cart (and/or a corral close to the field) could provide the labor for 0.75 hectare of zal.
In the current system, rainy season labor is fully utilized, especially during first weeding. The higher labor requirements for zai implies that something else will go undone.; The lower replanting rate for zai may offset some of the higher first weeding time. Composting may also have an impact on first weeding, because weed seeds are killed by the heat in properly prepared compost.
V. RESEARCHABLE ISSUES
Farmers and researchers have much to learn about zai and how it fits into the farming system of the central plateau. Most of the issues involve both agronomic and economic factors (Table 6). Table 6. Economic Research Issues Related to Zai Problem Economic Aspect*,
Plant density Labor time
Zai hole, shape and depth Labor time
Choice between zai and rock bunds Labor time
Amount of manure per hole Link to capital investment in livestock
production, also transport time
Benefits of manure vs compost Labor time for composting, water hauling,
Mechanization of zaf including soil Labor time and capital investment in
preparation and transporting manure equipment and draft animals
Animal production techniques that Labor for extra livestock handling, capital
increase usable manure for corrals, etc.
Forage production Profitability of livestock
Composting techniques that reduce water use Labor time, capital investments needed Manure extending techniques Labor time and capital
Manure fertilizer mixes Capital and/or cashflow
* All of the research issues here potentially affect the'distribution of yields and profits, and hence risk
For example, the optimal plant density is a function of both plant response and labor availability. The appropriate quantity of organic matter depends on soil characteristics, plant nutrition, labor times, capital costs and the profitability of livestock production.
This is a case where a systems perspective is essential. The current system is geared toward grain production for home consumption. Cash inputs are limited because the opportunity costs of capital are high and because the crops do not usually produce a cashflow to help pay for the purchases. Livestock are raised extensively and only a small proportion of animal waste is recovered for use as a soil amendment.
Za'f has the potential for creating a chain reaction within this extensive system. If za' improves yields and increases yield stability, farmers can starting thinking about other crop products, such as forage. The need for manure motivates farmers to confine livestock, but confined livestock need to be fed, increasing the demand for forage. If livestock production is made more profitable because of its link to za'i, cashflow generated by animal sales might be used to pay for fertilizer to extend manure availability. The interest in composting to extend manure supply and reduce weed pressure is also likely to increase.
Research requires foresight. RSP needs to be ready not only to address current problems, but also to be preparing itself for the problems that farmers will have in a few years. Research that addresses current problemswill always be behind. In the case of za'i a forward looking research strategy requires information on the direction of system evolution. The simplest tools for analyzing changes in a cropping system are farmer interviews and representative farm linear programming models.
Lowenberg-DeBoer, J., Daniel Kabor6 and Souleymane Ouedraogo, "Rapport de Mission A
Donsin, 10 Avril 1993," Projet ARTS, Universit6 Purdue, West Lafayette, Indiana.
PATECORE, "Rapport d'Activit6s Campagne 1988-1989," Kongoussi, Burkina Faso, Nov.
PATECORE, "Rapport d'Activit6s Campagne 1989-1990," Kongoussi, Burkina Faso, Nov.
PATECORE, "Rapport d'Activit6s Campagne 1990-1991," Kongoussi, Burkina Faso, Dec.
PATECORE, "Rapport d'Activit6s Campagne 199 1-1992," Kongoussi, Burkina Faso, Jan.
Sanou, Patrice and Alfred Ouedraogo, "Les strategies de conservation du milieui", INERA/RSP, Dec., 1992.
The Value of Research on Indigenous Knowledge: Preliminary Evidence from the Case of Za" in Burkina Faso
M. Bertelsen and S. Ouidraogo
Indigenous knowledge (IK) refers to the institutionalized but usually informal practice or practices which have evolved within a community in response to a particular problem or constraint. In the context of developing-country agriculture, whether IK is or is not anything more that just a new name for farmer practice (Erinle, 1993), it is clear that IK has achieved scientific respectability. There are good, practical reasons for this. IK practices are virtually always more "low-tech" using relatively plentiful and cheap labor more intensively than relatively scarce and expensive capital. Also, IK practices have evolved over many years and are therefore implicitly "sustainable": they are well adapted to the long-run local social, economic and environmental conditions. For this reason IK has attracted much attention in the natural resource management literature (Erinle 1994; Ou6danou 1994).
Two aspects make the study of IK especially interesting in a developing-country agriculture context. First of all, IK practices can be very localized reflecting evolved solutions to constraints imposed by conditions in a small area. Due to the lack of infrastructure and other factors which hinder information flows, the practices may not be adopted even in similar, nearby areas. Secondly, because IK practices were developed by farmers, they inspire confidence in other farmers and are therefore relatively easy to extend. Thus, the study of IK practices may provide large potential net social benefits: IK practices can have much to offer and can be extended relatively easily without incurring large costs.
The great majority of the scientific effort involving IK has so far been concentrated on the documentation of practices (see for example, Akinlosotu 1993, Ojeniyi 1993, Obi 1994, Maigida 1994). This necessary first step has been followed by attempts to adapt IK practices to new technologies with the intention of increasing production and returns to farmers (see for example, Otegbeye 1994, Gefu 1993). Until now, little effort has been directed toward estimating the value of IK practices themselves and, implicitly, the research which has brought these practices to light. This is what we propose to do in this paper; evaluate the potential impact of a particular IK practice in Burkina Faso with emphasis on the social value of the research which has made broader adoption possible.
Background. Zat is an agricultural practice which evolved in the central Sahelian Region of West Africa sometime during the first half of the 20th century. While its exact origins are unknown, it
Theodore Schultz (Schultz, 1969) first pointed out the relative efficiency of peasant agriculture. According to Schultz, the peasant fannrmer was '... relatively efficient in using the factors of production at its disposal" and that the key variable in explaining the differences in agricultural production was the level of acquired capabilities of farm people.
first appeared in the Yatenga Province of Northern Burkina Faso before 1950. Za" is a technique for improving the viability of sorghum and millet plantings. It involves the preparation of a small hole in the ground of about 25 30 cm in diameter and 10 cm deep (Kabor6 et al, 1993). Into this hole approximately 0.2 0.3 kg of manure or compost is placed before planting. Planting occurs in the hole after the first viable rains of the season. The effects of both the hole, which serves as a small reservoir for the plants, and the organic matter apparently combine to enable Za" plantings to vigorously establish themselves. As a result, re-plantings and the consequences of early, mini-droughts are often avoided. Increases in yield are dramatic. And although Za" demands the use of a great deal of additional labor, these demands occur during the dry season when the opportunity cost of labor is low relative to other times of the year.
Although Za" hasbeen practiced in Yatenga Province since at least 1950, the practice has not spread beyond this limited area. Farming Systems Researchers (RSP) of the Burkinabn National Agricultural Research Institute (INERA) became interested in the practice and decided to test the innovation in the similar RSP village site of Donsin., RSP transported a small group of Donsin farmers to Yatenga Province early in 1993 to see and discuss Zai with local farmers. Upon their return, this group very effectively extended the innovation to their neighbors. Approximate 70% of Donsin farmers tried Za" during the 1993 growing season (Robins et. al. 1994). RSP monitored the results of a random sample of these farmers during the season. RSP also established a Zar demonstration plot on highly degraded land to demonstrate the potential of this technique to reclaim land.
The methodology adopted for this study follows closely that developed by Akino and Hayami (1975). In the following figure, the adoption of an innovation causes the supply curve to shift out from a0S0 to a'0S1. As a result of this supply shift along the same demand curve Do, changes in social welfare occur. These changes are measured by changes in 'economic surplus'. Economic surplus is composed of two elements; consumers' surplus and producers' surplus. Consumer's surplus arises from the fact that a consumer pays only the marginal value of the last product sold in the market (market price) even though it is known from the law of diminishing marginal utility that previous units purchased were worth more (see any introductory economics text such as Samuelson, pp 448-449). Thus, at the initial market price of P0, consumers' surplus is equal to the area of triangle P0dp in Figure 1. Similarly, producers'surplus arises from the-fact that a producer receives the marginal cost (market price) for the last unit produced despite the fact that earlier units cost less to produce (law of diminishing returns). This corresponds to the area of triangle P0pa0 in Figure 1.
o 0 1 Quantity
Figure 1. Ex-Ante Analysis of Impact
The total net change in economic surplus occasioned by the change in supply is represented in the figure by the lightly shaded polygon. This area represents the total, ex-ante increase in social benefits (without partitioning between consumers and producers) and is equivalent to the theoretical measure described by Akino and Hayami.
Data. In order to estimate these social benefits, a great deal of data must be obtained. Specifically, data on price indices, market prices, quantities and estimates of the elasticities of demand and supply must be obtained. These are combined with estimates of adoption rates and yield increases in order to estimate probable changes in prices and quantities. Changes in costs of production and the costs of the research and extension programs must also be estimated. These baseline estimates are presented in Table 1 below.
Table 1. Baseline Data for the Analysis
1. Price of sorghum/millet 65
2. Price of soghum/millet stover/Kg3 10
3. National production of soghum & millet/yr (000 t)4 1,505,143
4. Potential Zai area in the North Zone a) Cattle (15/Ha/yr) 68,000
b) Sheep (53/Halyr) 44,000
c) Goats (97/Ha/yr) 30,000
d) Total hectarage in North Zone (Ha) 142,000
Assumption: Utilization of'10% total 14,200
e) Assumed adoption (Ha)/yr
5. Estimated cost of zai research program 1990-19955 5,000,000
6. Estimated cost of extention program 1995- 19996 10,000,000
7. Ave. Percentage increase in production/Ha7 84%
8. Elasticity of supply (sorghum/millet) 0.8
9. Elasticity of demand (sorghum/millet) 0.4
Additionally, we assume that 'off-season' household labor costs provide the only relevant costs differences for this analysis. The average opportunity cost of labor assumed for this period of time is 25 F CFA/hour. Any down-stream labor differences such as differences in weeding time stemming from the use of zai are ignored. No potential external costs are examined. Finally, we assume the productivity effects of zai last for two years and remain constant over this time period.
Some items in Table 1 require additional clarification. One limitation of the zai technology is the availability of manure (4). Using a conservative scenario, RSP researchers have estimated that some 15 cattle, 53 sheep or 97 goats are required to provide the manure sufficient for an average zai application (>8 tons/Ha). The GIS database indicates that there are sufficient livestock in the North Zone to provide manure for some 142000 hectares at this application rate. We suppose, however, that only about 10% (14,200) of this potential will be realized. This translates to about
6 hectares per village or about 0.04 hectares per exploitation in the North Zone.
Estimated average post-devaluation farm-gate price for soghum and millet.
3 Average estimated post-evaluation farm-gate price of soghum and millet stover.
4 Average of last nine years of sorghum and millet production. Source: Ministry of Agriculture. s Source: Estimate provided by RSP Program.
6 Source: Estimated provided by RSP Program. SSource: RSP monitoring survey, 1993-1994.
The adoption rate specified in (4e) assumes a doubling of hectarage in the North Zone every year for five years as a result of the extension program. The enthusiastic response of farmers in the RSP village site indicates this may also be a conservative assumption.
The most problematic estimations for the analysis are those for the elasticities of demand and supply (items 8 and 9). There are simply not any reliable and consistent estimates available. In the case of demand, it is highly likely that the real, "average" estimate we seek is less than one (inelastic) and probably much less than one. We accept 0.4 as a realistic estimate. Similarly, the supply elasticity is expected to be somewhat inelastic. We accept 0.8 as an reasonable estimate. Both estimates have been used in similar, regional analyses of impacts (Masters and Sanders, 1994). The results indicated below are much more sensitive to changes in the elasticity of supply than the elasticity of demand. As the elasticity of supply increases, the internal rate of return falls.
III. RESULTS: POTENTIAL VALUE OF ZAI AND IK RESEARCH
Table 2 presents an evaluation of the potential value of the zattechnique. It is assumed that the za" technology can be extended throughout the RSP North Zone, a homogeneous zone identified by the RSP Geographic Information System (GIS) unit. It was in this zone that the technology was developed and tested. The zone includes 10 provinces with atotal area of over 7 million hectares (see zone map).
Table 2. Economic evaluation of Za'
1. Average Net Profit (Zai over control, F CFA/Ha) 31,125
a) Total increase in profit per year by the 6th year 441.98 mil b) Value of the Zaitechnology 944.87 mil
1. Adoption rate doubles each year for 5 years
2. Present value discount rate = 20%
2. Increase in National Agricultural GDP (6th year) 503.04 mil
Percentage of Total AG GDP 0.07%
Percentage of total value of Sorghum production 1.10%
The average returns to zar have been estimated by RSP at 31125 F CFA/Ha (assuming an opportunity cost of off-season family labor at 25 F CFA/Hr). Accepting this value and the manure availability limitation, the regional net increase in farmer income is estimated to be about 442 million per year by the end of the 6th year (l a). The stream of income into perpetuity has a present value of some 945 million (lb) if one assumes a discount rate of 20% per year and the adoption rate assumed in Table 1 above.
Another way to express the potential benefits of za" is to consider the potential impact on Burkina's agricultural gross domestic product (GDP). Assuming the same levels of adoption in the same zone, agricultural GDP would rise some 503 million or by 0.07% of agriculture GDP by the end of the 6th year (2a). This figure represents an increase of 1.10% in the total value of national sorghum production (2b).
Rate of return to research. While the above figures indicate that za" has important potential, even with the conservative assumptions we have used, they say nothing about the social value of the RSP research which has made these results possible. Given the integrated nature of the RSP program and the large number of research themes addressed by RSP researchers during any given year, any allocation of the RSP budget to a specific theme is somewhat arbitrary. However, if one allocated a 5 million F CFA portion of the RSP research budget to za" each year from 1990 and through 1995 and one assumed a 10 million/year extension program to extend zar" beginning in 1995 and lasting though 1999, the resulting internalrate of return to research would exceed 50% for the 15 year period 1990 2004. This is illustrated in Table 3 below where estimated net social gains are also presented. If twice as much land were put into za" due to (say) collecting 20% of the manure instead of 10%, the returns would rise to almost 70% and the value estimates in Table 2 would double.
Our analysis of zar indicates that there may be very high potential social benefits stemming from the current trend towards studying
Table 3. Estimated program costs and net social gains* Research Year Costs Total Extension Real Cost Net Cost Social Gain
(nominal) (1994 CFA) (1994 CFA) (1994 CFA)
1990 5.0 0.0 5.0 6.26 -6.26
1991 5.0 0.0 5.0 6.19 -6.19
1992 5.0 0.0 5.0 6.26 -6.26
1993 5.0 0.0 5.0 6.19 -5.95
1994 5.0 0 5.0 5.00 -4.61
1995 5.0 10 15.0 15.00 -6.30
1996 0 10 10.0 10.00 7.39
1997 0 10 10.0 10.00 24.76
1998 0 10 10.0 10.00 59.53
1999 0 10 10.0 10.00 129.08
2000 0 0 0.00.00 278.20
2001 0 0 0.0 0.00 278.20
2002 0 0 0.0 0.00 278.20
2003 0 0 0.0 0.00 278.20
Internal Rate of Return: 52.71%
*Real Cost = nominal cost/price index
Net Social Gain = Gross Social Gain Real Cost
The RSP group identified za" as a potentially important IK practice, facilitated its transfer to another village and studied the impact. This relatively small investment has born very promising results. Using conservative assumptions, we estimate an internal rate of return to research on zal exceeding 50%.
The need to find sustainable solutions to agricultural and natural resource management problems compels development-related scientists to include IK in their research programs. In Burkina Faso as elsewhere, there are almost certainly other IK practices which are as promising as za but which need to be identified and extended to wider user groups. The RSP group in Burkina Faso plans to continue this important work.
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