Cowpea Cultivation in the Sahelian Region of West Africa: Farmers' Preferences and Production Constraints

Jpn. J. Trop. Agr. 50(4): 208-214, 2006 Cowpea Cultivation in the Sahelian Region of West Africa: Farmers' Preferences and Production Constraints Ryoichi MATSUNAGA1,4*, B. B. SINGH2, Moutari ADAMOU3, Satoshi TOBITA1, Keiichi HAYASHI1,4 and Akira KAMIDOHZONO1,4 1 Japan International Research Center for Agricultural Sciences (JIRCAS) 2 Kano Station, International Institute of Tropical Agriculture (IITA), Sabo Bakin Zuwo Road, PMB3112, Kano, Nigeria 3 Institut National de Recherches Agronmiques du Niger (INRAN), B.P. 429, Niamey, Niger 4 International Crops Research Insititute for the Semi-arid Troppics (ICRISAT) Niamey, BP12404, Niamey, Niger Abstract Genetic improvement to increase the yield performance of the cowpea [Vigna unguiculata (L.) Walp.] variety is a beneficial and affordable way to the poor farmers in the Sahelian region in West Africa. However, there is insufficient information on farmers' perception about the crop and the major production constraints in cowpea cultivation needed to facilitate the development of cowpea varieties suitable for the Sahelian region in West Africa. Therefore, a systematic on-farm survey was conducted to collect the latest information about cropping systems, cultural practices and major constraints in the cowpea production as well as farmers' preference for cowpea varieties in three typical villages in the Sahel. The results indicated that cowpea is mostly planted as an intercrop between pearl millet (Pennisetum glaucum) rows around two weeks after planting of millet and weed control was the most important practice during the cropping season. We found that insect-pests and low plant density should be the major constraints in cowpea production in the study area. The local varieties had common traits such as indeterminate spreading growth habit and white seeds with black eye. The farmers prefer dual purpose cowpea varieties with desired proportion of grain and fodder yields rather than mainly grain type and fodder type varieties. About two third of the farmers purchase cowpea seeds at the time of planting from the local market, due to strong demand of domestic consumption, sales in the local market for cash after the harvest and poor harvest of cowpea grains. The results obtained from farmers and cowpea fields in the study area could be useful to select cowpea varieties which are adaptable to the local environments and preferred by the farmers in the Sahel. Key Words: Dual-purpose Variety, Pests, Low plant density, Seed supply, Vigna unguiculata (L.) Walp. Introduction Cowpea [Vigna unguiculata (L.) Walp.] is one of the most important crops for the farmers in West Africa, particularly in the dry savannas and the Sahelian region. Singh et al.(2003) estimated from FAO statistics data that world land area planted for cowpea was 11.3 million hectares (1999-2000), with 9.3 million ha in West Africa, mainly in Niger (3.8 million ha), Nigeria (5 million ha) and Mali (0.5million ha). Although grain yield of cowpea is much lower than the potential yield in these countries (Singh et al., 2002), the low grain yield does not reduce its importance because of its multiple contributions to household food production, income generation as a cash crop, and soil fertility improvement. Cowpea is a low-p tolerant crop (Kolawale et al., 2000; Sanginga et al., 2000) and can utilize symbiotically fixed nitrogen as a nitrogen Received Apr. 13, 2006 Accepted Sept. 16, 2006 * Corresponding author 1-1 Ohwashi, Tsukuba, Ibaraki 305-8686, Japan Ryoichi_Matsunaga@jircas.affrc.go.jp source. Part of fixed nitrogen which remains in the decayed roots and nodules can contribute to subsequent crop cultivation. These unique characteristics are favorable to the poor soils in the Sahelian region, because nitrogen and phosphorus are the most limiting nutrients in the region (Bationo et al., 2002). Use of chemical fertilizer is limited mostly in African agriculture (Mokwunye and Hammond, 1992). Recent results of an on-farm survey showed that more than 90% of farmers in some villages of the northern Guinea savanna in Nigeria used chemical fertilizers, but the applied amount was less than half of the recommended, because of the high cost and inefficient marketing (Manyong et al., 2001). Obviously most small-holder farmers can not afford to apply a sufficient amount of both organic and inorganic resources to the soils in the sub-saharan African countries, and hence the limited application constrains the crop productivity of traditional production systems. In this situation food legumes having symbiotic fixation of air nitrogen and tolerance to low phosphorus soil are almost invariably included in the

Matsunaga et al.: Cowpea cultivation in the Sahel 209 farming systems in the Sahelian region in west Africa. Genetic improvement of cowpea germplasm is one of the efficient ways to alleviate the yield reduction caused by many kinds of stresses, and beneficial and affordable to the poor farmers particularly in the poor resource region such as the Sahel in West Africa. The International Institute of Tropical Agriculture (IITA) has been intensively carrying out cowpea breeding program, while only a few countries have the cowpea improving program such as Burkina Faso, Niger, Nigeria and Senegal in West Africa (Singh et al., 2003). IITA is successfully disseminating improved cowpea varieties to the farmers in the northern Nigeria (Singh et al., 2003; Kristjanson et al., 2005), while the dissemination is relatively slow in the Sahelian region. Therefore it is very essential to understand the stresses constraining performance of the local varieties and farmers' preference or dissatisfaction about their local varieties in order to select and disseminate new cowpea varieties which are adaptable to the local environments and to adoptable to the local farmer in the Sahel. In this study we conducted on-farm survey to collect latest information about cropping systems, cultural practices, production constraints and farmers' preference in three typical villages in the Sahel. Materials and Methods Interview with cowpea farmers in the study area The study area or Fakara is located around 60 km north-east from Niamey, the capital city of the Republic of Niger and lies within N13 20 Œ-N13 34 Œ, E2 33 Œ-E2 53 Œ (Fig. 1). The landscape consists of repeated toposequences from plateau to valley bottoms. The climate is typical of southern Sahel. The annual rainfall at the ICRISAT meteorological station of Dantiandou was 337.3, 544.7, 334.3 and 448.7mm in 2001-2004, respectively. The rainfall pattern is very erratic and variable within the rainy season in the study area. Major type of the soils in the area is Psammentic Paleustalfs with low fertility for the crop production. Fifty-seven and sixty-one cowpea farmers (Zarma tribe) were randomly selected for the 2004 and 2005 interviews, respectively, in three villages of Bani Zoumbou, Kodey, and Tchigo Tegui in the study area (Fig. 1). Some farmers were common between 2004 and 2005 interviews. The total number of households was 145, 135 and 100 in Bani Zoumbou, Kodey, and Tchigo Tegui, respectively in the 2004 survey and thus about 15-16% of households in the three villages were interviewed. Questionnaires were prepared in French to ask informants in local language about the cowpea cultivation, i.e. 1) the cropping system (mono-cropping or intercropping), 2) cultural calendar and practices, 3) the purpose of cultivation, and 4) perceptions of constraints in their cowpea fields. The interviews were conducted by Mr. Amadou Sodja (ICRSAT Research Technician) who lives in Dantinandou and can speak and understand French as well as local languages in the region. On-farm study in cowpea fields in the study area Incidences of insect-pests and diseases were carefully observed during the growing season in the study area in 2004. Towards the end of the cropping season sixty pearl millet/cowpea intercropping fields were surveyed around three villages (Banff Zoumbou, Kodey, and Tchigo Tegui) on 30 September and 1 October 2004. The incidence of diseases like Cercospora leaf spot (Cercospora canescens) in the surveyed fields was visually scored following a 0 to 5 scale as indicated below: Score Disease incidence 0 None of the plants infected 1 Less than 5% plants infected 2 From 5 to 10% plants infected 3 From 10 to 25% plants infected 4 From 25 to 50% plants infected 5 More than 50% plants infected In order to learn actual planting density at the sowing time the spot where plants were well established was selected in all the surveyed fields and spacings of millet and cowpea were measured. Major visible traits of the local varieties were also described on the fields. Results and Discussion Interviews with cowpea farmers in the study area Food legume crops are predominately intercropped in the cereal field in the dry savannas of West Africa (Wever, 1996). In the study area cowpea was mostly planted as an intercrop between pearl millet rows around two weeks later than millet sowing (Tables 1 and 2). More than half of the farmers also planted hibiscus (Hibiscus sabdariffa) as another component crop in their intercropping fields. Fifty-four farmers answered that grain production is the most important purpose of the cowpea cultivation, followed by fodder production and benefit for soil fertility in the 2004 interview (Table 3). This preference of the farmers to the grain and fodder harvests was very similar to that

210 J pn. J. Trop. Agr. 50 (4) 2006 Fig. 1 Insect-pests and deceases frequently observed in the cowpea fields in the study area. The insect-pests and deceases were identified according to the manual described by Singh and Allen (1978).

Matsunaga et al.: Cowpea cultivation in the Sahel 211 Table 1 Cowpea cropping systems on the fields of the study area (2004 interview) * Pennisetum glaucum ** Hibiscus sabdariffa, *** Number of responded farmers Table 2 Average planting date in the study area in the 2002 and 2003 seasons (2004 interview) in northern Cameroon (Kitch et al., 1998). Further question about the relative importance of grain and fodder harvests for the farmers (Table 4) in 2005 interview revealed that over two third of the interviewed farmers showed their preference to type 3 variety with 50% grain and 50% fodder of the best variety. Meanwhile 26% of interviewed farmers were interested in type 1 variety (i.e. grain-type variety) even though the variety is not able to produce any fodder. This result showed that around 70% of cowpea farmers prefer dual purpose cowpea variety which can have well proportionate production of grain and fodder rather than grain type and fodder type varieties. The cultural practices which farmers implemented in pearl millet/cowpea intercropping fields are presented in Table 5. Weeding was the most important practice for the farmers in the study area where nearly 100% of farmers carried out weeding. Some farmers answered that they did not go out of the village for off farm job until they finished the weeding. To maintain soil fertility in the fields, about 70% of farmers in the three villages used organic manure, while 23% used some amount of chemical fertilizer. Thus, most of the farmers depended mainly upon organic resources the soil fertility management. for It is a major contrast from the results of the on-farm survey in the northern Guinea Savanna of Nigeria where more than 90% of farmers used chemical fertilizer (Manyong, 2001). Most of the farmers (55 farmers, about 96%) are aware that cowpea cultivation has a positive effect on the soil fertility and soil conservation. Farmers in the northern Nigeria also recognized grain legumes such as soybean, groundnut and cowpea as improving soil nutrients (Manyong, 2001). Therefore, the benefit for soil fertility was found one of the important purposes of cowpea cultivation (Table 3) and thus might be one of the reasons for the farmers to continue the cultivation of cowpea in relatively infertile soils in spite of the low and unstable yields of cowpeas due to the heavy attack by various abiotic and biotic stresses. Table 3 The purpose of cowpea cultivation in the study area (2004 interview) * Farmers selected three to four purposes in important order and specified purpose when it was not listed in the questionnaire. ** Purposes which were listed in the questionnaire *** Nineteen farmers specified control of parasitic flowering plants (Striga hermonthica Benth.) on pearl millet as one of the purposes. Table 4 Farmers' preference to the production type of cowpea variety in the study area (2005 interview) *, ** The number of responded farmers and its percentage to all the responded farmers, respectively

212 Jpn. J. Trop. Agr. 50 (4) 2006 Table 5 Practices implemented on the fields of the study area (2004 Interview) *, ** The number of responded farmers and its percentage to all the responded farmers, respectively *** Direct application of animal excretions by mooring livestock on the field at night Jackai and Adalla (1997) described that insectpests posed the greatest threat to cowpea production and attacked cowpea from germination to storage. Forty-six of the 57 interviewed farmers (about 81%) answered that insect-pests attack was the most serious constraint to the cowpea production (Table 6). The most serious insect-pest mentioned by the farmers' was flower-feeding beetle (Mylabris spp) followed by pod-sucking bug (Anoplocnemis curvipes) in the 2005 interview. Sixty-seven percent of the farmers indicated that they purchased cowpea seeds at the time of planting from the local markets (Table 7). This is in complete contrast to the seed system of pearl millet in Niger, because 88% of the farmers saved their own millet seeds from the previous harvest (Ndjeunga, 2001). The major reason for the purchase of cowpea planting seeds was domestic consumption, followed by sales in local market for cash after the harvest and poor grain harvest (Table 8). On-farm survey in cowpea fields in the study area The on-farm survey of farmers' cowpea fields in the study area was done on 30 September and 1 October when most of the cowpea plants had reached the mid- or late pod-filling stage in all the fields. The cowpea varieties grown in all the fields had indeterminate spreading growth habit with white seeds and black eye. However, there was considerable variation in leaf shape; some with ovate leaves, some with intermediate Table 6 Farmers' perception of the constrains of cowpea production in the study area (2004 interview) * Farmers selected one to five constraint(s) in important order and specified constraint when it was not listed in the questionnaire. ** Constraints which were listed in the questionnaire *** Twenty three farmers specified as one of the constraints. It takes place between the flowering and pod-setting stages. Livestock eating, insufficient weed control and high seed cost were also specified once as one of the constraints. Table 7 Major sources of cowpea planting seeds for the following season in the study area (2004 interview) Table 8 Reasons for the purchase of cowpea seeds (2005 interview) *, ** The number of responded farmers and its percentage to all the responded farmers, respectively * Farmers selected three at maximum out of the reasons in the table. ** Number of responded farmers

Matsunaga et al.: Cowpea cultivation in the Sahel 213 leaves and another with narrow leaves. Hibiscus was also found on twenty-six of the surveyed fields, particularly on the periphery of the fields but detailed data about the hibiscus were not collected. In order to see actual planting pattern at the sowing time, the spot where plants were well established was selected in all the surveyed fields and spacings of pearl millet and cowpea were measured. Average spacings of pearl millet and cowpea were 166 ~ 134 cm and 261 ~ 190 cm, respectively. This spacing of cowpea was much lower than the recommended (e.g. 150 ~ 75 cm) (Reddy, 1988). The low density of cowpea plants should be one of major constraints to the cowpea production in the study area, although many farmers answered that such low density was Table 9 Reasons for the sparse sowing of cowpea seeds on the fields of the study area (2005 interview) good for the cowpea growth (Table 9). Infestation of insect-pests such as flower-feeding beetles (Mylabris spp) and pod-sucking bugs (Anoplocnemis curvipes, Clavigralla tomentosicollis and Nezara viridula), and the incidence of diseases such as Cercospora leaf spot (Cercospora canescens) and golden mosaic virus, and parasite organism (Striga gesneriodes) were frequently observed on the cowpea plants in the study area during the 2004 growing season (Fig. 2). Particularly the incidence of Cercospora leaf spot was observed in all the surveyed fields on 30 September and 1 October (Fig. 1). Cowpea plants infected with golden mosaic virus were found only in the fields around Kodey village (Data were not shown). Although many farmers recognized that insect-pests were threatening cowpea harvest (Table 6), none of them used any control measures to check insect-pests and diseases (Table 3). The results obtained from the farmers and cowpea fields in the study area provide a good view of the farmers' preferences and the present constraints in cowpea cultivation in Sahelian region. The results highlight a clear need to develop dual-purpose cowpea * Farmers selected three out of the reasons in the table at maximum. ** Number of responded farmers varieties higher grain as well as fodder yields combining resistance to Cercospora leaf spot and insect-pests. Another traits such as tolerance to drought and good growth under low fertility should be also involved for the better selection of cowpea varieties which are adaptable to the local environments and adoptable to the farmers in the Sahelian region in West Africa. References Bationo, A., B. R. Ntare, S. A. Tarawali and R. Tabo 2002. Soil fertility management and cowpea production in the semiarid tropics In: Challenges and opportunities for enhancing sustainable cowpea production. (Fatokun, C. A., S. A. Tarawali, B. B. Singh, P. M. Kormawa, and M. Tamð eds.) IITA (Ibadan, Nigeria) 301-318. Jackai, L. E. N. and C. B. Adalla 1997. Pest management practices in cowpea: a review. In: Advance in Cowpea Research. (Singh, B. B., D. R. Mohan Raj, K. E. Dashiel and L. E. N. Jackai eds.) Sayce Publishing,(Devon, UK) 240-258. Kitch, L. W., O. Boukar, C. Endondo and L. L. Mursock 1998. Farmer acceptability criteria in breeding cowpea. Expl Agric. 34: 475-486 Fig. 2 Location of the study area (Fakara) in Niger (lower) and incedence of Cercospora leaf spot (Cercospora canescens) in the cowpea fields in the study area (upper). Note:,,,, œ and œ indicate no incidence (0% of the plants in the field), very slight (less than 5%), slight (5 to 10%), medium (10 to 25%), severe (25 to 50%) and very severe (more than 50%), respectively. Curved lines in the study area show roads and lanes. Kolawale, G. O., G. Tian, and B. B. Singh 2000. Differential response of cowpea varieties to aluminum and phosphorus application. J. Plant Nutr. 23: 731-740. Kristjason, P., I. Okike, S. Tarawali, B. B. Singh and V. M. Manyong 2005. Farmers' perceptions of benefits and factors affecting the adoption of improved dual-purpose cowpea in the dry savannas of Nigeria. Agriclitural Economics 32: 195-210. Manyong, V. M., K. O. Makinde, N. Sanginga, B. Vanlauwe and J. Diels 2001. Fertilizer use and definition of farmer domains

214 Jpn. J. Trop. Agr. 50 (4) 2006 for impact oriented research in the northern Guinea savanna of Nigeria. Nut. Cycl. Agroecosyst. 59: 129-141. Mokwunye, A. V. and L. L. Hammond 1992. Myths and science of fertilizer use in the tropics. In: Myths and science of soils of the tropics. (Lal, R. and P. A. Sanchez eds.) SSSA Special Publication No 29.(Madison, Wisconsin, USA) 121-135. Njdeunga, J. 2001. Local village seed systems and pearl millet seed quality in Niger. Expl. Agric. 38:149-162. Reddy, K. C. 1988. Storatgies alternatives pour la production de mil/niebe pendant L'hivernage. Istitut National de Recehrches Agronomiques du Niger Fascicule no 1: 1-28. Sanginga, N. 2003. Role of biological nitrogen fixation in legume based cropping systems; a case study of West Africa farming systems. Plant Soil 252: 25-39. Sanginga, N., O. Lyasse and B. B. Singh 2000. Phosphorus use efficiency and nitrogen balance of cowpea breeding lines in a low P soil of the derived savanna zone in West Africa. Plant Soil 220: 119-128. Singh, B. B., H. A. Ajeigbea, S. A. Tarawali, S. Fernandez-Riverac and M. Abubakaret 2003. Improving the production and utilization of cowpea as food and fodder. Field Crops Research 84:169-177. Singh, S. R. and D. J. Allen 1978. Manual No. 2: The insect-pests and deceases of cowpea. IITA (Ibadan, Nigeria) p.113. Singh, B. B., J. D. Ehlers, B. Sharma and F. R. Freire Filho 2002. Recent progress in cowpea breeding. In: Challenges and opportunities for enhancing sustainable cowpea production. (Fatokun, C. A., S. A. Tarawali, B. B. Singh, P. M. Kormawa, and M. Tamð eds.) IITA (Ibadan, Nigeria) 22-40. Weber, G. 1996. Legume-based technologies for African savannas: challenges for research and development. Biol.. Agric. Hort. 13: 309-333. 2 Kano Station, International Institute of Tropical Agriculture (IITA Kano), Sabo Bakin Zuwo Road, PMB3112, Kano, Nigeria 3 Institut National de Recherches Agronmiques du Niger (INRAN), B.P. 429, Niamey, Niger 4 International Crops Research Insititute for the Semi-arid Troppics (ICRISAT) Niamey, BP12404, Niamey, Niger