AGRICULTURE URBAINE ET PÉRIURBAINE POUR LA SÉCURITÉ ALIMENTAIRE EN AFRIQUE DE L'OUEST. LE CAS DES MICRO-JARDINS DANS LA MUNICIPALITÉ DE DAKAR

In the context of Urban and Peri-urban Agriculture (UPA) micro-gardens, a simplified version of hydroponics, represent an interesting opportunity for producers, because they are characterized by a high efficiency in the use of water (2-3 l/m2/per day) and by a great spatial versatility. Moreover the vegetables grown through this technique are of high quality, because quality water and no chemical pesticide are used. These characteristics improve the poorest families’ access to horticultural products, they contribute to diet diversification of poor (and also non poor) families and thanks to surplus selling they answer the need to create an extra source of income. As this activity is mainly based on recycled materials (pallets, old tyres, bins, plastic bottles and bags as containers, peanut shells and rice hulls for the substrate), its environmental impact is undeniably important. Our study, which took place in Dakar in the framework of a project of decentralized cooperation between the municipality of Milan and the Senegalese capital, proved micro-gardens’ excellent production performances. Cultivation on solid substrate can provide 7-9 kg /m2 of tomatoes, and up to 15 kg/m2 of cucumbers. In floating system peppermint can produce up to 1,5 kg/m2 and lettuce 35 heads/m2. Very good productions and low costs offer the rising micro-gardens production chain some interesting opportunities of economical development, and profitability studies underlined its economic sustainability. In fact our study demonstrated that a group of producers possessing 10 containers (1 m2 each) can afford to buy inputs needed for production by selling half of its production (10 m2 can bring up to 230 000 F CFA/a year, that is to say about 340 euros.) In the last few years attempts were made to introduce compost to enrich solid substrate, in order to diminish the amount of mineral fertilizers now employed. Productions aren’t fully satisfying yet, but the further development of this technique could be crucial in the management of urban organic wastes. The benefits of micro-gardens and of UPA in general are also very important on the social and cultural plane. First of all they offer integration opportunities to marginalized groups (old, disabled people, women, young people). Moreover their introduction into schools offer the possibility to cater their canteens and to organize several didactic activities. Finally through the experience of micro gardens people appropriates of two extremely important concepts: those of food safety and food security. The necessity to improve the food and environmental situation in towns of developing countries is stressed by demographic projections: in 2025 more than half the population of developing countries - about 3,5 billion people - will live in towns. The recent history of the development of conurbations in Southern countries lets us foresee that towns will rapidly grow to the expenses of former rural spaces, increasing food insecurity, unemployment, social exclusion, environmental degradation. UPA may be able to permit a partial u-turn: increased food security, job creation, environmental sustainability. From the specific case of micro-gardens our research extended to the rest of Dakar region, to the town of Cotonou (Benin) and to West Africa in general, in the attempt to give a general outline of UPA in the sub-region and to identify its advantages, potentialities, limits and associated risks. The case studies of Cotonou and Dakar, which are especially deepened in this study, are particularly meaningful: in both towns UPA nourishes and offers a job to quite a big percentage of the population, it can play a key environmental role and experience the two limits that, in our opinion, mainly obstacle its development. In fact UPA in Cotonou is limited by the access to the land, especially because of its geographical position (the town in fact is constricted between the ocean on one side and the lagoon on the other) and by the competition for other urban uses. In Dakar access to land is similarly a problem, worsened by the difficulties to accede good and safe water resources. In this sense micro-gardens seem to be destined to increase their importance in the context of UPA in the sub-region. Moreover both case studies stressed the importance of a greater integration of UPA in urban planning, and the utility that Geographical Information Systems (GIS) can have as decision support.