Les fruits et les noix

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Les fruits et les noix contribuent à la sécurité alimentaire, à la nutrition et à la génération de revenus en Afrique. Ces cultures fournissent des apports en vitamines et en micronutriments importants dans les régimes alimentaires des populations. Elles constituent également des matières premières dans plusieurs secteurs notamment dans les industries pharmaceutique et cosmétique. Les déchets et les sous-produits organiques, tels que les pulpes et les coques, issus de la transformation des fruits et des noix peuvent être transformés en produits à valeur ajoutée et en aliments pour animaux.

La mangue, l’ananas, le café, la banane plantain et la banane sont quelques exemples de fruits largement cultivés qui sont d’importantes cultures commerciales et / ou des aliments de base essentiels pour l’Afrique. Les amandes, les pistaches et les noix de cajou sont entre autres des noix produites pour la demande locale et pour l’exportation vers les pays occidentaux et l’Asie.

Les contraintes liées à la production de fruits et de noix en Afrique comprennent les systèmes traditionnels à faibles intrants, les maladies et les ravageurs, les pertes post-récoltes élevées dues à la périssabilité des produits et la mauvaise conservation, les effets du changement climatique et les faibles taux d’adoption des meilleures pratiques.

Christine B. Schmitt, Daniel Kisangau and Kennedy W. Matheka. 2019. Tree diversity in a human modified riparian forest landscape in semi-arid Kenya. Forest Ecology and Management (433): 645-655 pp.

Riparian forests in tropical drylands support high biodiversity and provide crucial ecosystem services. Yet, fertile soil, water availability and trees as a source of charcoal and timber make them a favourable place for settlements and subsistence agriculture. The present study aimed at evaluating the floristic diversity of riparian forest remnants in semi-arid Kenya as a basis for developing conservation and management strategies. Plant diversity was assessed along the Nzeeu and Kalundu rivers in Kitui County, Eastern Province, where riparian forest patches were intermingled with agricultural and grazing lands and invasive thickets dominated by Lantana camara. Diameter at breast height (DBH) and height of woody species (DBH > 5 cm) were recorded in a total of 74 transects (50m×10 m) laid out perpendicular to the rivers on both sides at 300m intervals. In each transect, the distribution of six land cover types was mapped out and the distance of each plant individual from the river bank was noted. Overall, 631 individuals were recorded representing 85 woody species, of which 12 were exotic timber and fruit trees. The study highlights that the area still supports viable remnants of indigenous riparian vegetation, whereas tree diversity on agricultural land is strongly shaped by human preferences and shows lack of recruitment. Targeted management interventions could support the maintenance of indigenous tree diversity with positive effects for overall biodiversity, soil protection and livelihood diversification. For instance, it is recommended to facilitate natural tree regeneration and to plant a variety of indigenous tree species, especially on the river banks. Further research is necessary to assess the status of riparian vegetation along similar dryland rivers in Kenya and Africa to adequately manage these important areas for biodiversity and ecosystem services.
Show details Posted by : Dr. Christine B. Schmitt

Jemal Omarsherif, Callo-Concha Daniel, van Noordwijk Meine. 2018. Local Agroforestry Practices for Food and Nutrition Security of Smallholder Farm Households in Southwestern Ethiopia. Sustainability (10 (8))

Food and nutrition security (FNS) rests on five pillars: availability, access, utilization, stability, and sovereignty. We assessed the potentials of local agroforestry practices (AFPs) for enabling FNS for smallholders in the Yayu Biosphere Reserve (southwestern Ethiopia). Data was collected from 300 households in a stratified random sampling scheme through semi-structured interviews and farm inventory. Utility, edibility, and marketability value were the key parameters used to determine the potential of plants in the AFPs. Descriptive statistics, ANOVA, and correlation analysis were employed to determine the form, variation, and association of local AFP attributes. Homegarden, multistorey-coffee-system, and multipurpose-trees-on-farmlands are the predominant AFPs in Yayu. Multipurpose-trees-on-farmlands are used mainly for food production, multistorey-coffee-system for income-generation, and homegarden for both. The 127 useful plant species identified represent 10 major plant utility groups, with seven (food, fodder, fuel, coffee-shade, timber, non-timber-forest-products, and medicinal uses) found in all three AFPs. In total, 80 edible species were identified across all AFPs, with 55 being primarily cultivated for household food supply. Generally, household income emanates from four major sources, multistorey-coffee-system (60%), homegarden (18%), multipurpose-trees-on-farmlands (13%), and off-farm activities (11%). Given this variation in form, purpose, and extracted benefits, existing AFPs in Yayu support the FNS of smallholders in multiple ways.

Show details Posted by : Arthur

Chala Bilhate, Oechsner Hans, Latif Sajid, Müller Joachim. 2018. Biogas Potential of Coffee Processing Waste in Ethiopia. Sustainability (10)

Primary coffee processing is performed following the dry method or wet method. The dry method generates husk as a by-product, while the wet method generates pulp, parchment, mucilage, and waste water. In this study, characterization, as well as the potential of husk, pulp, parchment, and mucilage for methane production were examined in biochemical methane potential assays performed at 37 °C. Pulp, husk, and mucilage had similar cellulose contents (32%). The lignin contents in pulp and husk were 15.5% and 17.5%, respectively. Mucilage had the lowest hemicellulose (0.8%) and lignin (5%) contents. The parchment showed substantially higher lignin (32%) and neutral detergent fiber (96%) contents. The mean specific methane yields from husk, pulp, parchment, and mucilage were 159.4 ± 1.8, 244.7 ± 6.4, 31.1 ± 2.0, and 294.5 ± 9.6 L kg−1 VS, respectively. The anaerobic performance of parchment was very low, and therefore was found not to be suitable for anaerobic fermentation. It was estimated that, in Ethiopia, anaerobic digestion of husk, pulp, and mucilage could generate as much as 68 × 106 m3 methane per year, which could be converted to 238,000 MWh of electricity and 273,000 MWh of thermal energy in combined heat and power units. Coffee processing facilities can utilize both electricity and thermal energy for their own productive purposes.

Show details Posted by : Arthur

Callo-Concha Daniel, Ewert Frank. 2014. Using the Concepts of Resilience, Vulnerability and Adaptability for the Assessment and Analysis of Agricultural Systems. Change and Adaptation in Socio-Ecological Systems, Volume 1, Issue 1, ISSN (Online) 2300-3669

Resilience, vulnerability and adaptability have emerged as dominant concepts in the study of disturbance and change of social-ecological systems. We analyze the conceptual, methodological and operational aspects in using these concepts for the assessment and analysis of agricultural systems and try to identify differences and possible overlaps between them. The analysis is performed considering a number of published studies on agricultural systems over a wide geographical range where these concepts have been applied. Our results show a clear conceptual overlap and often the exchangeable use of the concepts. Furthermore, the driving methodological and operational criteria for their application could not be separated unambiguously. It was, thus, difficult to identify guiding principles for the operational application of the individual concepts. We stress that the operationalization of these concepts requires consistency in the approaches and protocols to ensure their coherent use. We also argue that the conceptual and operational integration of resilience, vulnerability and adaptability would perhaps lead to a more complete portrayal of the behavior of agricultural systems in changing situations. But this requires more research including the development of operational protocols for which the premises of complexity, participation and functionality seem key.

Show details Posted by : Arthur

Malabo Montpellier Panel.2018.Mechanized: Transforming Africas Agriculture Value Chains.Dakar.

The current report—Mechanized: Transforming Africa’s Agriculture Value Chains—summarizes the findings of a systematic analysis of what countries at the forefront of progress in mechanization have done right. It analyzes which policy decisions were taken and which interventions were implemented to substantially increase the uptake of mechanization. The report takes a broad perspective on mechanization, including technologies along the entire value chain and how they relate to agricultural development and job creation.
Show details Posted by : Jelana Vajen

Julian Philipp Wald, Donatus Nohr, Hans Konrad Biesalski. 2018. Rapid and easy carotenoid quantification in Ghanaian starchy staples using RP-HPLC-PDA. Journal of Food Composition and Analysis (67): 119-127 pp.

This study comprises the development of a robust, rapid and cost-effective reversed-phase high-performance liquid chromatographic method with low solvent consumption (micro-approach) to quantify carotenoids in starchy staples, exemplified for cassava, maize and plantain matrices. For extraction, a mixture of 1 M potassium hydroxide in methanol and hexane (1:1) was used, enabling the simultaneous extraction and saponification of the sample extracts. Carotenoids were separated within 12 min on a C30 column using mixtures of methanol, methyl tert-butyl ether and water as mobile phases. Due to the implemented saponification process, the technique showed the potential to be applied for carotenoid analysis in other sample matrices exemplarily demonstrated for green leafy vegetables. Because of the low application and equipment costs, the analytical procedure qualifies for its application in quality management with limited budget. Concentrations of five major dietary carotenoids (lutein, zeaxanthin, β-cryptoxanthin, α-carotene and β-carotene) in cassava, cocoyam, yam, maize and plantain samples from the Ashanti region of Ghana were determined. Based on the restricted data on carotenoid contents of food available in West Africa, the results provide valuable additional information that can be used to expand local food composition tables and support the assessment of dietary carotenoid intake.

Show details Posted by : Julian Philipp Wald

O. A. Amoakoh, D. D. N. Nortey, F. Sagoe, P. K. Amoako and C. K. Jallah. 2017. Effects of pre-sowing treatments on the germination and early growth performance of Pouteria campachiana. FOREST SCIENCE AND TECHNOLOGY (VOL. 13, NO. 2, ): 83–86 pp.

Pouteria campachiana is a multipurpose fruit tree with diverse economic and medicinal significance. However, seed dormancy and low germination are problems for its use in agro-forestry practices. Investigations were carried out on the effect of pre-treatment on the germination and early seedling growth of P. campachiana. Germination was observed in seeds pre-treated with soaking and mechanical scarification in the 5th week after sowing, while untreated seeds germinated in the 7th week. Comparison between mechanically scarified and unscarified P. campachiana seeds showed no significant difference (P > 0.05). The study showed that soaking P. campachina seeds in cold water was not good for its germination, with a significant difference between soaked seeds and non soaked seeds. Percentage germination of seeds not soaked was 62.2% compared to 26.7% and 24.4% recorded for seeds soaked for 24 h and 48 h, respectively. The application of different pre-treatments, however, had no significant (P > 0.05) influence on the mean shoot length, collar diameter, and the number of leaves of P. campachiana. The study concludes that mechanical scarification improves germination of P. campachiana while soaking with cold water has a negative influence on seed germination.

Show details Posted by : Alex Owusu Amoakoh

Christine B. Schmitt, Ulrike Grote. 2008. Wild coffee production in Ethiopia: the role of coffee certification for forest conservation. Berlin Conference on the Human Dimensions of Global Environmental Change (17-18 / 11/ 2008). Berlin, Germany.

The Ethiopian rainforests are internationally renowned for their high biodiversity and their wild coffee (Coffea arabica) populations, but are severely threatened by deforestation. The remaining rainforests are used for wild coffee production. This study quantifies wild coffee yields from local management systems without artificial inputs, and analyses the impact of wild coffee management on the natural forest vegetation. Subsequently, the role of coffee certification for forest conservation is evaluated. The results show that wild coffee yields from undisturbed forest with low management intensity are extremely small. Intensive management in semi-forest coffee systems removes 30 % of the canopy trees and most undergrowth vegetation. This stimulates wild coffee growth and almost triples coffee yields, while jeopardizing forest biodiversity. Premium prices for wild coffee through certification are seen as one possibility to halt the deforestation process by adding economic value to the natural coffee forests. Particular certification criteria for wild coffee, however, do not exist yet. This study reviews currently present coffee certification schemes under, e.g., Forest Stewardship Council (FSC), International Federation of Organic Agriculture Movements (IFOAM), Rainforest Alliance and Utz Kapeh, and explores to what extent they can promote sustainable use and conservation of the Ethiopian coffee forests.

Show details Posted by : Dr. Christine B. Schmitt

Christine B. Schmitt, Feyera Senbeta, Manfred Denich, Helmut Preisinger and Hans Juergen Boehmer. 2010. Wild coffee management and plant diversity in the montane rainforest of southwestern Ethiopia. African Journal of Ecology (48): 78–86 pp.

Coffea arabica occurs naturally in the montane rainforests of Ethiopia, but large areas of these unique forests have been converted to other land-uses. In the remaining forest, wild coffee is managed and harvested with increasing intensity because of rising coffee prices in the world market. This study evaluated the impact of coffee management on wild coffee populations and the forest vegetation as a basis for conservation planning in southwestern Ethiopia. Vegetation surveys and yield assessments were carried out in unmanaged natural forest and in managed semi-forest coffee (SFC) systems. Analyses show that wild coffee density and coffee yields were low in natural forest (max. 15 kg / ha / year). In SFC systems, 30% of the canopy trees and most undergrowth vegetation were removed. This stimulated wild coffee growth and strongly enhanced yields (max. 54 kg / ha / year), but severely disturbed forest structure. Species richness increased by 26% because of an increase in species of ruderal and secondary vegetation; however, species richness and abundance of typical forest species declined. Conservation of the natural forest therefore requires the control of wild coffee management. Wild coffee certification is discussed as one tool to reconcile conservation measures and the interests of local farmers.

Show details Posted by : Dr. Christine B. Schmitt