Browsing by Author "Marc J.J. Janssens"

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    Diversity of plants in cocoa agroforests in the humid forest zone of Southern Cameroon
    (Springer Science+Business Media B.V., 2007) Denis J. Sonwa; Bernard A. Nkongmeneck; Stephan F. Weise; Maturin Tchatat; Akin A. Adesina; Marc J.J. Janssens
    In the humid forest zone of Southern Cameroon, farmers generally associate cocoa with native and exotic trees in complex agroforestry systems. Despite the socioeconomic and ecological importance of these systems, few studies have investigated their plant composition. We investigated tree composition of cocoa agroforests along a gradient of market access, population density and resource use intensity in the humid forest zone of southern Cameroon, comprising (i) the sub-region of Yaounde´, (ii) the sub-region of Mbalmayo, and (iii) the sub-region of Ebolowa. Market access, population density and resource use intensity all decreased from the first to the third sub-region. We quantified the diversity of tree species associated with cocoa within individual agroforests, among agroforests in the same region, and among the three sub-regions, and classified the tree species according to their main uses. A total of 9.1 ha belonging to 60 cocoa agroforests were inventoried in 12 villages. We encountered a total of 206 tree species with an average of 21 tree species per agroforest. In the more urbanized area around Yaounde´, agroforests were less diverse than in the other sub-regions. In all of the agroforests, food producing tree species tended to be more frequent than other species. Two thirds of the food trees were native forest species and one third was introduced. From Ebolowa to Yaounde´, the density of food producing trees doubled and the density of exotic food-producing species increased relative to native species. Some local species producing high-value non-timber forest products were found in the agroforests, but their density was far lower than that of exotic tree species. The agroforests also provide medicine, charcoal and other products for household consumption and sale. We conclude that unless there are specific efforts to promote local forest tree species in cocoa agroforests, these will progressively lose importance with increasing market access, population pressure and land use intensity.
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    Management of cocoa: Constraints during acquisition and application of pesticides in the humid forest zones of southern Cameroon
    (Elsevier, 2008) Denis J. Sonwa; Ousmane Coulibaly; Stephan F. Weise; Akinwumi Adesina, A.; Marc J.J. Janssens
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    Management of cocoa: Constraints during acquisition and application of pesticides in the humid forest zones of southern Cameroon
    (2008) Denis J. Sonwa; Ousmane Coulibaly; Stephan F. Weise; Akinwumi Adesina, A.; Marc J.J. Janssens
    Subsidies for inputs, such as pesticides, enabled about 400000 households in southern Cameroon to grow cocoa and provide Tor basic needs such.as food, education, bride price and house construction. Economic liberalization resulted in disengagement of the State in favor of the private sector and engendered a new behavior pattern among cocoa farmers. This study focuses on the constraints inherent in the acquisition and application of pesticides for cocoa growing on small farms in the tropical rain forest areas of southern Cameroon. Over 50% of farmers use chemical pesticides, but the high cost and lack of availability in rural areas are cited, respectively by 65% and 55% of cocoa farmers as major constraints by users of pesticides. Only 21% of cocoa farmers buy their pesticides in the village. Fungicides are the main pesticide used to control Phytophthora megakarya, but farmers do not apply the recommended application rate so production is low. Some farmers form groups to circumvent production problems, while some use plant extracts. To increase production it is essential to improve safe practices in the purchase, transportation; storage, handling and application of pesticides and promote integrated pest management in southern Cameroon.