Influence du changement climatique sur la diversité inter et intra-spécifique des plantes cultivées à Tougou au nord du Burkina Faso

L’objectif de l’étude est d’évaluer la diversité taxonomique et la variabilité inter et intra-spécifique des plantes cultivées non spontanées dans un contexte de changement climatique. Les données sont collectées à l’aide d’une enquête au près de 75 producteurs menée suivant des interviews semi-structurées. Les résultats ont révélé l’existence de 122 écotypes appartenant à 49 espèces, 39 genres et 22 familles. La diversité interspécifique représentait 73% de la diversité des plantes cultivées au plan national. La variabilité intraspécifique était faible comparée à la variabilité au plan national. Elle était plus élevée chez les céréales et les cultures potagères pluviales avec 2 à 10 écotypes par espèce contre 1 à 3 écotypes par espèce chez les cultures maraîchères. Les écotypes ayant un cycle de plus de 90 jours représentant 10,5% de l’ensemble des écotypes recensés, sont menacés de disparition à cause du changement climatique. Une stratégie de collecte, de conservation, d’amélioration et de promotion de ces ressources ainsi que la restauration des écosystèmes dégradés s’avèrent nécessaire pour le maintien de la phytodiversité cultivée.Mots clés: Burkina Faso, agro biodiversité, écotype, espèces menacées, conservatio

Effets de fertilisants organique et organomineral a base de dechets vegetaux et animaux sur la croissance et le rendement du soja (Glycine max (L.) Merrill) en zone de savane de Cote d’Ivoire

La culture du soja, en Côte d’Ivoire, n’occupe pas la place qu’elle mérite malgré ses potentialités bénéfiques et les conditions favorables. Aussi, la fertilisation minérale, aux apports certains à la culture, demeure-t-elle coûteuse et inaccessible aux petits paysans. Cette étude vise à évaluer les effets de fertilisants organique et organo-minéral d’origines végétale et animale sur la croissance et le rendement du soja (Glycine max (L.) Merr). Le dispositif expérimental utilisé est un bloc de Fisher randomisé, avec quatre répétitions et quatre traitements que sont le témoin, la fumure minérale, la fumure organique et la fumure organo-minérale. La fumure minérale a été appliquée à des doses de 24 kg ha-1 N, 45 kg ha-1 P2O5 et 36 kg ha-1 K2O. La dose des fumures organique et organo-minérale était de 10 t ha-1. La fumure minérale a permis d’obtenir une meilleure croissance des plants durant les quarante-cinq premiers jours du cycle cultural. Pendant les quarante-cinq derniers jours du cycle, la fumure organo-minérale a eu les meilleurs effets. La fumure organique a, quant à elle, impacté favorablement le nombre de gousses (250) et la masse de 1000 graines (112,25 g). Cependant, le rendement en graines le plus élevé a été obtenu dans le traitement témoin (1,06 t ha-1). Ainsi, l’utilisation de fumure organo-minérale ne semble pas nécessaire pour la culture du soja, mais plutôt la fumure organique en cas de déficience du sol en matière organique, tout en comblant le déficit hydrique pendant la phase de production.Mots clés: fumure organique, fumure organo-minérale, croissance, rendement, soja, Côte d’IvoireEnglish Title: Effects of organic and organo-mineral fertilizers on soybean productivity in the savanna zone of Côte d’IvoireEnglish AbstractSoybean cultivation, in Côte d’Ivoire, is lagging despite its beneficial potential and favorable conditions. Also, the mineral fertilization remains expensive and inaccessible to small farmers. This study aims to evaluate the effects of organic and organo-mineral manure of vegetable and animal origins on the soybean growth and yield (Glycine max (L.) Merr). The experimental design used is a randomized Fisher block with four replicates and four treatments, namely control, mineral manure, organic manure and organo-mineral manure. The mineral manure was applied at doses of 24 kg ha-1 N, 45 kg ha-1 P2O5 and 36 kg ha-1 K2O. The dose of organic and organo-mineral manure was 10 t ha-1. The mineral manure allowed to obtain a better growth of plants during the first forty five days of the cultural cycle. During the last forty five days of the cycle, the organo-mineral manure had the best effects. The organic manure impacted favorably on the number of pods (250) and the mass of 1000 seeds (112,25 g). However, the highest seed yield was obtained in the control treatment (1.06 t ha-1). Thus, the use of organo-mineral manure does not seem necessary for the culture of the soybean, but  rather the organic manure in case of soil deficiency in organic matter, while covering the hydrous deficit during the production phase.Keywords: organic manure, organo-mineral manure, growth, yield, soybean, Côte d’Ivoire

Fertilisation des sols avec la litiere foliaire en zone Subsahelienne du Burkina Faso: Diversite des especes, effets sur les rendements du sorgho

Organic matter sources management for soil fertility improvement has been the subject of many researches. Agroforestry is one of the topics addressed by these researches. In Burkina Faso\u2019s Northern Center, leaf litter of woody species is collected, piled, crumbled before spreading in fields. This practice is not well known in the rest of the country. The present study aims to provide information on the diversity of spontaneous plant species concerned, farmers\u2019 motivations of litter crumbling and to evaluate, empirically the effects of litter spreading on sorghum yields. A participatory study, using qualitative surveys and biometric field measurements, was conducted in five villages in the Northern Center of Burkina Faso. Because of their availability, accessibility, and agronomic performance, plants such as Vitellaria paradoxa , Anogeissus leiocarpa , Combretum micranthum , Lannea microcarpa and Diospyros mespiliformis were the species whose leaf litter was valued most. Measurements achieved in situ indicate that sorghum yields from fields that received Vitellaria leaf litter for the first time were lower than those in the control plots. On the other hand, fields that received this litter for three consecutive years were more productive. A scientific study on leaf litter chemical characteristics and their influence on soil fertility parameters should be considered in order to validate local knowledge and to improve knowledge about these practices.La gestion des sources de mati\ue8res organiques, pour am\ue9liorer la fertilit\ue9 des sols, a fait l\u2019objet de nombreuses recherches. L\u2019agroforesterie est une des th\ue9matiques abord\ue9es par ces recherches. Dans le Centre-Nord du Burkina Faso, la liti\ue8re foliaire des esp\ue8ces ligneuses est ramass\ue9e, mise en tas, \ue9miett\ue9e avant d\u2019\ueatre \ue9pandue dans les champs. Cette pratique est peu connue dans le reste du pays. La pr\ue9sente \ue9tude visait \ue0 fournir des informations sur la diversit\ue9 des esp\ue8ces v\ue9g\ue9tales spontan\ue9es concern\ue9es, les motivations paysannes de l\u2019\ue9miettement de la liti\ue8re et \ue0 \ue9valuer, empiriquement et par des mesures, les effets de l\u2019\ue9pandage de ces liti\ue8res sur les rendements du sorgho. Une \ue9tude participative, \ue0 l\u2019aide d\u2019enqu\ueates qualitatives et des mesures biom\ue9triques dans des champs, a \ue9t\ue9 men\ue9e dans cinq villages du Centre Nord du Burkina Faso. A cause de leur disponibilit\ue9, leur accessibilit\ue9, leur performance agronomique, les plantes telles que Vitellaria paradoxa , Anogeissus leiocarpa , Combretum micranthum , Lannea microcarpa , Diospyros mespiliformis ont \ue9t\ue9 cit\ue9es comme \ue9tant les esp\ue8ces dont la liti\ue8re des feuilles est valoris\ue9e. Les mesures r\ue9alis\ue9es in situ montrent que, les rendements du sorgho dans les champs ayant re\ue7u de la liti\ue8re foliaire de Vitellaria pour la premi\ue8re fois, ont \ue9t\ue9 inf\ue9rieurs \ue0 ceux des parcelles t\ue9moin. Par contre, les champs ayant re\ue7u cette liti\ue8re pendant trois ann\ue9es cons\ue9cutives ont \ue9t\ue9 plus productifs. Dans l\u2019optique de valider les savoirs locaux et d\u2019approfondir les connaissances sur l\u2019effet des liti\ue8res foliaires sur la fertilit\ue9 du sol, une \ue9tude scientifique sur leur caract\ue9ristique chimique et sur leur influence sur les param\ue8tres de fertilit\ue9 du sol, est \ue0 envisager

Perennial grass ley rotations with annual crops in tropical Africa: a review

Open Access Article; Published online: 18 Feb 2021Rotation of grass ley with periods of annual crop production can be a means to increased farming system productivity, sustainability, and profitability. This research review offers interpretations of rotation research results for future African agriculture. Some rotation studies were with naturally generated and severely over-grazed fallows consisting primarily of annual plant species but other studies were with planted and well-managed perennial grass ley. Generally, the rotations increased annual crop yields with soil improvement. System benefits were similar or greater for ley compared with fallow with generally higher fodder yields with ley. Surface crusting of sandy soil in the Sahel is a major concern that may be worsened by fallow due to the deposition of clay and silt particles. Ley and fallow were terminated in all studies with inversion plow tillage with more tillage for subsequent crops while the rotation benefits may be greater with less tillage. Most studies did not have fertilizer use but annual crop yield response to fertilizer was greatly increased following ley in one study and with no system by fertilizer interaction effect in three studies. The profitability of ley rotations will vary with fodder demand which is rapidly increasing, especially near urban areas. Strip cropping, for example, alternate ley with annual crop strips of 5–20 m width and rotation cycles of 6–10 yr, may often be optimal for erosion control and sediment trapping, protection from uncontrolled grazing, and nearby supply of vegetative planting material for ley re-establishment. Rotation management can be improved through experiential learning and experimentation

Environmentally friendly tool to control mosquito populations without risk of insecticide resistance: the Lehmann's funnel entry trap.

BACKGROUND: Current malaria control strategies have cut down the malaria burden in many endemic areas, however the emergence and rapid spread of insecticide and drug resistance undermine the success of these efforts. There is growing concern that malaria eradication will not be achieved without the introduction of novel control tools. One approach that has been developed in the last few years is based on house screening to reduce indoor mosquito vector densities and consequently decrease malaria transmission. Here screening and trapping were combined in one tool to control mosquito populations. The trap does not require an insecticide or even an attractant, yet it effectively collects incoming resistant and susceptible mosquitoes and kills them. RESULTS: Performance of the funnel entry trap was tested in low and high malaria vector density areas. An overall reduction of 70 to 80% of mosquito density was seen in both. Species and molecular forms of Anopheles gambiae identification indicated no variation in the number of Anopheles arabiensis and the molecular forms of An. gambiae between houses and traps. Mosquitoes collected in the traps and in houses were highly resistant to pyrethroids (0.9 kdr-based mechanism). CONCLUSION: There is a global consensus that new intervention tools are needed to cross the last miles in malaria elimination/eradication. The funnel entry trap showed excellent promise in suppressing mosquito densities even in area of high insecticide resistance. It requires no chemicals and is self-operated

Chemical and microbial properties of farmer’s field soils fertilized with municipal solid wastes without pretreatment in the peri-urban zone of Ouagadougou, Burkina Faso

Peri-urban agriculture can contribute to food security and nutrition in developing countries. However, due to rising mineral fertilizer prices, farmers in these countries such as Burkina Faso are supplying the required nutrients to their fields by adding municipal solid waste (MSW). This uncontrolled use of waste matter that is not treated could pose several risks on soil quality. The aim of this study was to evaluate the impact on chemical and microbial soil properties of this nasty, but current practice. The study investigated the chemical and microbial characteristic of soils receiving different quantity of waste for several years (20, 10 and 7 years). Soils were sampled around the city of Ouagadougou (Burkina Faso). Soil chemical (C, N, P and pH) and microbial (basal respiration, microbial biomass and microbial diversity) characteristics were assessed. A comparison between unamended soils and the amended ones revealed that the MSW increased soil C, N and P content up to 2 fold. The increase was higher in the 20 years old field that received MSW. The microbial biomass evaluated by the substrate induced respiration method was significantly higher in soils fertilized with MSW, while the microbial activity determined by 21-day soil respiration was not significantly different between treatments. The catabolic diversity was not significantly different. These results suggested that the accumulated organic matter in supplied MSW soils would present particular properties notably a slight biodegradability. This study showed that while the chemical characteristic was related to different quantity of MSW, through different years applied, the microbial activities were not significantly modified. The informal quantity and quality added were discussed.© 2010 International Formulae Group. All rights reserved.Keywords: Urban, agriculture, soil, carbon, nitrogen, SIR, microbial activity