Cartographie des directions dominantes des vents au Benin : Outil de conception et de dimensionnement des ouvrages

La présente étude a pour objet de déterminer les directions dominantes du vent et d'établir une carte région-vent du Bénin. Pour ce faire, nous avons, après la collecte des informations météorologiques, procédé : - à l’analyse des données (directions) des six stations météorologiques principales conformément aux méthodes statistiques. Ces données couvrent une période de 23 ans ; - au moyen des techniques numériques, à l’analyse des variations des directions ; - à l’analyse selon la norme AFNOR de l’influence du relief et de la végétation sur les directions. A l’issue de cette étude, nous avons établi des cartes régions appropriées. The present study aims to determine dominant directions of the wind and to establish a wind-region map of Benin. In order to do that, we have after the collection of meteorological information carried out: - the analysis of data (directions) of the six main meteorological stations in accordance with statistical methods. These data cover a period of 23 years; - the analysis of the variations of directions by means of numerical techniques; - the analysis of the influence of the relief and the vegetation on directions according to AFNOR norms. At the end of this study, we established appropriate regions maps

Thirty years of water management research for rice in Sub-Saharan Africa: achievement and perspectives

Rice is one of the major staple foods in sub-Saharan Africa (SSA) and is mainly grown in three environments: rainfed upland and rainfed and irrigated lowlands. In all rice-growing environments, the yield gap (the difference between the potential yield in irrigated lowland or water-limited yield in rainfed lowland and upland and the actual yield obtained by farmers) is largely due to a wide range of constraints including water-related issues. This paper aims to review water management research for rice cultivation in SSA. Major water-related constraints to rice production include drought, flooding, iron toxicity, and soil salinity. A wide range of technologies has been tested by Africa Rice Center (AfricaRice) and its partners for their potential to address some of the water-related challenges across SSA. In the irrigated lowlands, the system of rice intensification and alternate wetting and drying significantly reduced water use, while the pre-conditions to maintain grain yield and quality compared to continuous flooding were identified. Salinity problems caused by the standing water layer could be addressed by flushing and leaching. In the rainfed lowlands, water control structures, Sawah rice production system, and the Smart-Valleys approach for land and water development improved water availability and grain yield compared to traditional water management practices. In the rainfed uplands, supplemental irrigation, mulching, and conservation agriculture mitigated the effects of drought on rice yield. The Participatory Learning and Action Research (PLAR) approach was developed to work with and educate communities to help them implement improved water management technologies. Most of the research assessed a few indicators such as rice yield, water use, water productivity at the field level. There has been limited research on the cost-benefit of water management technologies, enabling conditions and business models for their large-scale adoption, as well as their impact on farmers’ livelihoods, particularly on women and youth. Besides, limited research has been conducted on water management design for crop diversification, landscape-level water management, and iron toxicity mitigation, particularly in lowlands. Filling these research gaps could contribute to sustainable water resources management and sustainable intensification of rice-based systems in SSA