Variabilite spatiale des rendements du riz en systeme de riziculture intensive (SRI) en zone office du Niger au Mali

Une étude exploratoire a été menée de 2009 à 2013 en vue d’évaluer la faisabilité technique du Système de Riziculture Intensive (SRI) dans cinq localités de l’Office du Niger. Le protocole expérimental comprenait 3 traitements : pratique paysanne avec la dose recommandée de fumure minérale (T1) ; méthode SRI avec 10 tonnes de fumier plus la dose d’engrais recommandée (T2) et méthode SRI avec 10 tonnes de fumier et la moitié de la dose vulgarisée de fumure minérale (T3). En plus, deux essais factoriels comprenant les combinaisons fumier X azote et phosphore X azote ont été conduits en station. Durant les 3 années d’étude, les rendements ont varié entre 4,5 et 10 t ha-1 et plus avec la méthode SRI et entre 3 et 8t ha-1 avec la méthode conventionnelle. En outre, une relation positive entre les pratiques de gestion des cultures et les rendements en milieu paysan a été observée. Il en a été de même pour les rendements et les facteurs sol notamment N et P. Dans près de 50 % des cas, la variabilité des rendements pouvait être expliquée par des pratiques culturales, et de gestion de la fertilité et de l’eau.Mots clés : Système de Riziculture Intensive, variabilité spatiale, facteur sol, fertilisation minérale, fumie

Evaluation de la fertilité des sols et les rendements de cotonnier, maïs et sorgho à >Gliricidia sepium (Jacq.) Kunth ex. Walp

De nos jours, la carence en fertilité des sols est un problème très répandu dans la plupart des pays subsahariens. G. sepium a été testé en association avec le cotonnier, le maïs et le sorgho afin de développer les meilleures pratiques dans deux stations de recherche et en milieu paysan dans les zones soudaniennes et soudano-guinéenne du Mali. L'objectif de cette étude était de développer, avec les producteurs participants, une technologie agro-forestière basée sur le Gliricidia sepium dans le système de culture en couloir. Le dispositif expérimental utilisé a été le Split plot à quatre répétitions. Le pH, le carbone organique du sol et l'azote ont été analysé dans des échantillons de sol de 0 à 20 cm de profondeur prélevés en 2016 au début de l'expérience et en 2018. Les rendements grains moyens de coton, de maïs et de sorgho associés au G. sepium étaient respectivement de 812, 1457 et 1377 kg.ha-1, alors qu'ils étaient significativement plus faibles sans G. sepium, avec 623, 1014 et 807 kg.ha-1 respectivement. Pendant la troisième année suivant la plantation de G. sepium, la teneur en carbone organique et en azote total du sol a augmenté de 5% dans les sols situés entre les allées. Le G. sepium en association avec les cultures a le potentiel d'améliorer leurs rendements et le sol.Mots clés : Carbone organique, azote, rendements, zones soudanienne et soudano-guinéenne, Mali English Title: Evaluation of Gliricidia sepium (Jacq.) Kunth ex. Walp effect on soil fertility, yields of cotton, maize and sorghum Nowdays, soil fertility deficiency is a widespread issue in most Sub-Saharian countries specially where the application of less input is the common agricultural practices. Thus the legume plant, G. sepium was established with cotton, maize and sorghum to develop best practices for increasing crop yield and soil fertility at two research stations and farming environment in the Sudanian and Sudano-Guinean zones of Mali. The objective of this study was to develop an agroforestry technology with farmers based on Gliricidia sepium in alley cropping system. The experimental design was Split plot with four replications. Soil pH, soil organic carbon and nitrogen were analyzed from 0-20 cm deep soil samples taken in 2016 at the beginning of the experiment and in 2018. Mean grain yields of cotton, maize and sorghum associated with G. sepium were 812, 1457 and 1377 kg.ha-1, respectively, while they were significantly lower without G. sepium with 623, 1014 and 807 kg.ha-1 as respectively cotton, maize and sorghum yield. In the third year after planting G. sepium, the soil organic carbon and total nitrogen content increased by 5% between the alleys. G. sepium in association with crops has the potential to improve crop yields and soil fertility.Keywords: Gliricidia sepium, organic carbon, nitrogen, yields, Mali

Seasonality and Prevalence of Leishmania major Infection in Phlebotomus duboscqi Neveu-Lemaire from Two Neighboring Villages in Central Mali

Phlebotomus duboscqi is the principle vector of Leishmania major, the causative agent of cutaneous leishmaniasis (CL), in West Africa and is the suspected vector in Mali. Although found throughout the country the seasonality and infection prevalence of P. duboscqi has not been established in Mali. We conducted a three year study in two neighboring villages, Kemena and Sougoula, in Central Mali, an area with a leishmanin skin test positivity of up to 45%. During the first year, we evaluated the overall diversity of sand flies. Of 18,595 flies collected, 12,952 (69%) belonged to 12 species of Sergentomyia and 5,643 (31%) to two species of the genus Phlebotomus, P. duboscqi and P. rodhaini. Of those, P. duboscqi was the most abundant, representing 99% of the collected Phlebotomus species. P. duboscqi was the primary sand fly collected inside dwellings, mostly by resting site collection. The seasonality and infection prevalence of P. duboscqi was monitored over two consecutive years. P. dubsocqi were collected throughout the year. Using a quasi-Poisson model we observed a significant annual (year 1 to year 2), seasonal (monthly) and village effect (Kemena versus Sougoula) on the number of collected P. duboscqi. The significant seasonal effect of the quasi-Poisson model reflects two seasonal collection peaks in May-July and October-November. The infection status of pooled P. duboscqi females was determined by PCR. The infection prevalence of pooled females, estimated using the maximum likelihood estimate of prevalence, was 2.7% in Kemena and Sougoula. Based on the PCR product size, L. major was identified as the only species found in flies from the two villages. This was confirmed by sequence alignment of a subset of PCR products from infected flies to known Leishmania species, incriminating P. duboscqi as the vector of CL in Mali

Discrepant Prevalence and Incidence of Leishmania Infection between Two Neighboring Villages in Central Mali Based on Leishmanin Skin Test Surveys

Leishmaniasis is a vector-borne disease transmitted to humans by the bite of an infected sand fly. Leishmaniasis is present in more than 88 countries and affects more than 12 million people. Depending on the species of Leishmania, the host can develop cutaneous leishmaniasis (CL), which is characterized by skin ulcers in uncovered parts of the body or a more severe form, visceral leishmaniasis, which affects the liver and spleen and is fatal if not treated. This study aims to establish the past and present infection with Leishmania parasites in two villages where recent cases have been diagnosed by the dermatology center (CNAM) in Bamako. This was achieved using a Leishmania-specific skin test that was administered annually to permanent residents of Kemena and Sougoula villages from 2006 to 2008. The results show that transmission of Leishmania is active and stable in these two villages. Moreover, despite sharing similar cultural and environmental features, the individuals from Kemena presented three times the risk of Leishmania infection compared with those from Sougoula. Our findings raise awareness of the continued presence of CL in Mali

Windborne long-distance migration of malaria mosquitoes in the Sahel

Over the past two decades efforts to control malaria have halved the number of cases globally, yet burdens remain high in much of Africa and the elimination of malaria has not been achieved even in areas where extreme reductions have been sustained, such as South Africa1,2. Studies seeking to understand the paradoxical persistence of malaria in areas in which surface water is absent for 3–8 months of the year have suggested that some species of Anopheles mosquito use long-distance migration3. Here we confirm this hypothesis through aerial sampling of mosquitoes at 40–290 m above ground level and provide—to our knowledge—the first evidence of windborne migration of African malaria vectors, and consequently of the pathogens that they transmit. Ten species, including the primary malaria vector Anopheles coluzzii, were identified among 235 anopheline mosquitoes that were captured during 617 nocturnal aerial collections in the Sahel of Mali. Notably, females accounted for more than 80% of all of the mosquitoes that we collected. Of these, 90% had taken a blood meal before their migration, which implies that pathogens are probably transported over long distances by migrating females. The likelihood of capturing Anopheles species increased with altitude (the height of the sampling panel above ground level) and during the wet seasons, but variation between years and localities was minimal. Simulated trajectories of mosquito flights indicated that there would be mean nightly displacements of up to 300 km for 9-h flight durations. Annually, the estimated numbers of mosquitoes at altitude that cross a 100-km line perpendicular to the prevailing wind direction included 81,000 Anopheles gambiae sensu stricto, 6 million A. coluzzii and 44 million Anopheles squamosus. These results provide compelling evidence that millions of malaria vectors that have previously fed on blood frequently migrate over hundreds of kilometres, and thus almost certainly spread malaria over these distances. The successful elimination of malaria may therefore depend on whether the sources of migrant vectors can be identified and controlled

Utilisation of wastewater for fuel and fodder production and environmental and social benefits in semi-arid, peri-urban zones of sub-Saharan Africa. Final Report 1/12/2002 - 30/11/2007 Contract number ICA4-CT-2002-10017

The overall objective was to develop low-tech water treatment and irrigation systems and test their use for the production of fuel wood and fodder in semi-arid sub-Saharan Africa. Sites for waste water treatment plants and irrigation systems were identified and the systems were constructed in Burkina Faso, Mali and Niger. Project partners were trained in how to use and maintain the systems. The irrigation sites were characterised in advance of tree planting, and soil and water analyses are being conducted regularly. Tree species with potential for use in irrigated conditions in each country were identified and experimental designs for the trials produced. Some species were used in common in all three countries. Nursery screening trials were conducted and plants were then planted at the irrigation sites. Trees grew quickly under the irrigated conditions and many species performed well. Species which were selected for their good performance in the nursery were not necessarily the best performers in the field. Biomass production was determined and the effects of different coppicing treatments on regrowth were assessed. Parameters of planting stock quality were assessed and incidence of pest attacks determined. Partners were also trained in the use of sap flow and associated equipment. Considerable variation between tree species in water use was noted, together with differential effects according to the inoculation history of the plants. Working in controlled glasshouse conditions, using sterilised soil media, considerable variation in effectiveness of different mycorrhizal strains on different tree species was detected. When plant response to simulated irrigation water was measured, uninoculated plants grew very poorly irrespective of whether they are receiving the simulated irrigation water or not. Thus mycorrhizal infection enabled plants to make use of the nutrients in the irrigation water. Initially, nursery and field studies gave much less clear results. However, assessments during the final year of the project demonstrated positive effects of inoculation on tree growth in Mali and Niger. These observations were reinforced on the rhizobial side by molecular studies, using strain-specific probes for nodule analysis. In Ouagadougou it was estimated that 225,004 tons of fuel wood and 6708 tons of charcoal per year are transported to the city. The average price of firewood was approximately 21 F CFA per kg, and charcoal was 60 – 110 F CFA per kg. Sellers can achieve a substantial income from sales. The large quantities of fuel imported into Ouagadougou highlight the pressure on fuel resources. This is further indicated by the observations in Niger and Mali. Dissemination to stakeholders has been conducted and is continuing. The irrigation sites are continuing to be run. An important development is the formation of a partnership with representative farmers’ organizations regrouped under the umbrella of ROPPA (Réseau des Organisations Paysannes et des Producteurs Agricoles d’Afrique de l’Ouest, who federates millions of farmers through twelve west African countries, with the objective of bringing symbionts to farmers

Utilisation of wastewater for fuel and fodder production and environmental and social benefits in semi-arid, peri-urban zones of sub-Saharan Africa. Fifth Annual Report: 1/12/2006 – 30/11/2007

Summary Report Since the beginning of the contract, the results achieved are as follows: Work package 1 Water treatment and irrigation Sites for waste water treatment plants and irrigation systems were identified and the systems have been constructed in Burkina Faso, Mali and Niger. Progress was slower than planned for a variety of reasons, including delays to obtaining permits for construction, delays associated with importation and shipping of components and delays in purchase of expensive items due to cash flow problems. Staff have been trained in how to use and maintain the systems. Some modifications and refinements and repairs have been necessary, but systems are functioning in each country. The irrigation sites were characterised in advance of tree planting, and soil and water analyses are being conducted regularly. Work package 2 Tree growth and management Tree species with potential for use in irrigated conditions in each country were identified and experimental designs for these trials were produced. Some species are being used in common in all three countries. Nursery screening trials were conducted and plants were then out planted to the irrigation sites. Trees have grown quickly under the irrigated conditions and many species are performing well. Few problems have been detected. Species which were selected for their performance in the nursery are not necessarily the best performers in the field plots. In this year, biomass production has been determined and the effects of coppicing at 2 different heights on regrowth have been assessed. Work package 3 Tree water use and soil water status Staff in all three countries with irrigation systems have received training in the use of sap flow, soil water and associated measuring equipment. In Mali, considerable variation between tree species in soil water use has been noted, together with differential effects according to the inoculation history of the plants. Acacia angustissima appears to have particularly high water use and is easily water-stressed, whereas A. mangium appears to be more robust in its performance. Even with irrigation, tree water use is declining by the late morning, indicating stomatal closure. In Burkina Faso, L. hybrid showed the highest transpiration rate (1.09 L cm-2 day-1), followed by L. leucocephala (0.93 L cm-2 day-1), G. sepium (0.93 L cm-2 day-1) and A. angustissima (0.61 L cm-2 day-1). Gliricidia did not show morning stomatal closure, whereas Acacia and the Leucaenas did. Stomatal closure was especially marked with Acacia angustissima, confirming the results previously obtained in Mali. The long term use of physiological equipment under tropical conditions has proved difficult as the equipment is not particularly robust. Work package 4 Microsymbionts and N fixation Working in controlled glasshouse conditions, using sterilised soil media, the UK partner has identified considerable variation in effectiveness of different mycorrhizal strains on different tree species. After the initial screening phase, selected tree species were taken on to the second phase of the study in which plant response to simulated irrigation water is being measured. Uninoculated plants grew very poorly irrespective of whether they are receiving the simulated irrigation water or not. The response of inoculated plants to irrigation varied with inoculant and tree species. Initially, nursery and field studies in Mali, Niger and Burkina Faso gave much less clear results. However, assessments during this final year of the project have demonstrated positive effects of inoculation on tree growth in Mali and Niger. These observations are reinforced by molecular studies, using strain-specific probes for nodule analysis, which have been successfully tested against the inoculants, studies on samples collected from the field experiments in Mali suggest that the inoculant strains are absent – other types are present. This suggests that either the original inoculation was unsuccessful, or that the inoculants have been out-competed by indigenous strains. Work package 5 Economics and quality of produce Questionnaires have been developed by the partner in Niger, in collaboration with other partners. All countries have now completed their surveys, which have generated a considerable amount of useful information about fuel wood and fodder supplies. For Ouagadougou (population 960000 in 2000), it is estimated that 225,004 tons of fuel wood and 6708 tons of charcoal per year are transported to the city. The average price of firewood was approximately 21 F CFA per kg, and charcoal was 60 – 110 F CFA per kg. Sellers can achieve a substantial income from sales. The large quantities of fuel imported into Ouagadougou highlight the pressure on fuel resources. This is further indicated by the observations in Niger, where wood cutters cut an average of 27 steres per month, and each village can have 40 – 80 woodcutters. In Mali, annual wood fuel consumption averages about 0.5 ton per capita, and collection of a cart load of wood can involve a journey of 30 km and 3 days. Increasing numbers of grazing cattle are creating conflicts between different land uses. Assessments of fuel wood quality and palatability to animals have been made in Mali. Work package 6 Soil and plant nutrition Nutrient contents of irrigation water and soil nutrient status are being monitored at each site. In Mali, studies showed that pesticide levels were not significant, but that there was sometimes a build up of ammonium and turbidity in water flowing out of the plantation. In Burkina Faso microbiological analyses showed that the water treatment was successful in reducing levels of bacteria. Analyses have continued in all countries and no problems have been detected. Work package 7 Planting stock quality Studies have been conducted in Burkina Faso and Mali. Using various parameters of planting stock quality (shoot: root ratio, sturdiness quotient, Dickson’s Quality Index), considerable variations in quality have been identified, between species, production methods and between partners testing the same species. In Burkina Faso, a previous pot experiment was planted out. Previous effects of inoculation, substrate and pot size were no longer evident, however there was considerable variation between species in growth. At the time of planting, there were considerable differences in shoot: root ratios between species. Work package 8 Pest monitoring and management Studies in Mali have highlighted attack by termites on Leucaena and Calliandra, causing death of experimental trees, and the susceptibility of Acacia angustissima to prolonged flooding