Institute Of Recherche Agronomique Of Guinee

Conakry, Guinea

Institute Of Recherche Agronomique Of Guinee

Conakry, Guinea
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Diedhiou A.G.,CIRAD - Agricultural Research for Development | Diedhiou A.G.,Laboratoire Communications Of Microbiologie | Diedhiou A.G.,British Petroleum | Selosse M.,CNRS Center of Evolutionary and Functional Ecology | And 8 more authors.
Environmental Microbiology | Year: 2010

The diversity of ectomycorrhizal (ECM) fungi on adult trees and seedlings of five species, Anthonotha fragrans, Anthonotha macrophylla, Cryptosepalum tetraphyllum, Paramacrolobium coeruleum and Uapaca esculenta, was determined in a tropical rain forest of Guinea. Ectomycorrhizae were sampled within a surface area of 1600 m2, and fungal taxa were identified by sequencing the rDNA Internal Transcribed Spacer region. Thirty-nine ECM fungal taxa were determined, of which 19 multi-hosts, 9 single-hosts and 11 singletons. The multi-host fungi represented 92% (89% when including the singletons in the analysis) of the total abundance. Except for A. fragrans, the adults of the host species displayed significant differentiation for their fungal communities, but their seedlings harboured a similar fungal community. These findings suggest that there was a potential for the formation of common mycorrhizal networks in close vicinity. However, no significant difference was detected for the δ13C and δ15N values between seedlings and adults of each ECM plant, and no ECM species exhibited signatures of mixotrophy. Our results revealed (i) variation in ECM fungal diversity according to the seedling versus adult development stage of trees and (ii) low host specificity of ECM fungi, and indicated that multi-host fungi are more abundant than single-host fungi in this forest stand. © 2010 Society for Applied Microbiology and Blackwell Publishing Ltd.

Camara A.A.,Institute Of Recherche Agronomique Of Guinee | Dugue P.,CIRAD - Agricultural Research for Development | De Foresta H.,IRD Montpellier
CyberGeo | Year: 2012

A comparative analysis of the spatio-temporal evolution of mosaics of forest-savannas subject to local agricultural practices was conducted in two tropical areas (Forest Guinea, Centre of Cameroon). During the last three decades, the spatial influence of the agro-forest systems or «agroforest»associating perennial crops (cocoa, coffee⋯) and sub-spontaneous vegetation, strongly increased in these two regions. In Guinea, these systems, mainly based on coffee trees, developed to the detriment of spaces formerly dedicated to annual crops (pluvial rice) in rotation with fallow trees or shrubs. But a dynamic of extension of agroforests with coffee trees in the units of savannah has begun. In the centre of Cameroon, agroforest, mainly with cocoa trees, was implanted first of all in forest relicts and forest galleries. Then, due to lack of forest reserves, the farmers innovated by developing and expanding over large areas of agroforests in the zones of savannah with grasses, traditionally devoted to food-producing annual crops. This dynamic, far from being destructive, contributes to the constitution of an ecosystem «cultivated forester»or agroforest, in regions originally dominated by the savannah and the secondary forest. Faced with these relatively recent processes, the issue of sustainability of agroforests is raised, because of the increase of demand for food therefore needs land for annual crops.

Saidi S.,CIRAD - Agricultural Research for Development | Camara A.,Institute Of Recherche Agronomique Of Guinee | Gazull L.,CIRAD - Agricultural Research for Development | Passouant M.,CIRAD - Agricultural Research for Development | Soumare M.,Institute dEconomie Rurale IER
International Journal of Agricultural and Environmental Information Systems | Year: 2013

This article presents a lowland mapping method for the Forested Guinea (Guinée Forestière) using a 30 m resolution Digital Elevation Model (DEM) that is currently the best option to analyze large forested areas. This low cost DEM method applies surface topography analysis processes to better discriminate areas with stagnant and/or accumulated water. The main index selected is the immediate proximity of flat areas to drainage network, the former with slope gradients not exceeding 5% (2.86°). The mapped lowlands potential cover a surface of 4516 km2, i.e., 10% of the total area of the region with hydro-agricultural potential. © 2013, IGI Global.

Tendonkeng F.,University of Dschang | Fogang Zogang B.,University of Dschang | Sawa C.,Institute Of Recherche Agronomique Of Guinee | Boukila B.,Université des Sciences et Techniques de Masuku | Pamo E.T.,University of Dschang
Tropical Animal Health and Production | Year: 2014

Recent investigations suggest that the development of multinutrient feed blocks with inclusion of tree and shrub leaves could improve the nutritive value and digestibility of straw. In order to test these possibilities, three types of multinutrient blocks (MNB) namely: MNB0 (wheat bran = 100 %; Tithonia diversifolia leaf = 0 %), MNB50 (wheat bran = 50 %; T. diversifolia leaf = 50 %) and MNB100 (wheat bran = 0 %; T. diversifolia leaf = 100 %) were fed for 15 days in a 3 × 3 Latin square arrangement to West African dwarf goats consuming Brachiaria ruziziensis straw. The blocks presented a good cohesion and a good hardness. The inclusion of T. diversifolia improved levels of crude protein, mineral, feed unit for milk production (UFL) and feed unit for meat production (UFV), but decreased palatability. The effects on the digestibility of B. ruziziensis straw were evaluated in nine West African dwarf goats fed individually with MNB0 + straw, MNB50 + straw and MNB100 + straw. The dry matter, organic matter and crude fibre digestibility of B. ruziziensis straw increased slightly with increasing level of inclusion of T. diversifolia. The apparent digestibility of nitrogen was comparable for all diets independent of the level of inclusion of T. diversifolia. This study showed that the inclusion of T. diversifolia leaves in the MNBs can be recommended to improve the feeding of goats during periods of drought. © 2014 Springer Science+Business Media Dordrecht.

Zogang Fogang B.,University of Dschang | Boukila B.,Université des Sciences et Techniques de Masuku | Sawa C.,Institute Of Recherche Agronomique Of Guinee | Tendonkeng F.,University of Dschang | And 2 more authors.
Livestock Research for Rural Development | Year: 2012

The study of physical characteristics and palatability of Tithonia diversifolia based multinutrient blocks (MNBs) as supplement to Brachiaria ruziziensis's straw in Djallonke ewes was conducted at the Teaching and Experimental Farm, University of Dschang in 2011. Three types of MNB namely BMN0 (wheat bran: 100%; leaves of T. diversifolia: 0%), BMN50 (wheat bran: 50%; leaves of T. diversifolia: 50%) and BMN100 (wheat bran: 0% leaves of T. diversifolia: 100%) were used for this study. The physical characteristics (drying, cohesion, hardness and color) of blocks were evaluated during 20 days of drying sheltered from sunlight and in well-ventilated area. A Latin square arrangement (3x3) was used to assess the palatability and intake of multinutrient blocks associated with B. ruziziensis hay for Djallonké ewes. The results of this study showed that the blocks showed good cohesion and good hardness. The colors ranged from light to dark changing according to the level of inclusion of leaves of T. diversifolia. Drying increased with increasing level of inclusion of leaves of T. diversifolia. The ingestion of the MNB was 32.06 ± 12.67, 26.08 ± 6.34 and 27.87 ± 10.15 gMS/J/kgPV 0, 75 corresponding to a palatibility of 40,2 32,5 and 35,5%, respectively for BMN0, BMN50 and BMN100. This study found that the inclusion of leaves of Tithonia diversifolia gives not only good physical characteristics with BMN, but also a palatability that decreases with the inclusion of T. diversifolia's leaves.

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