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Cocoa (Theobroma cacao L.) growing is traditionally practised after forest clearance and is gener... more Cocoa (Theobroma cacao L.) growing is traditionally practised after forest clearance and is generally considered to be one of the main deforestation factors in the tropics, as in Ivory Coast, where the forest area declined from 13 million hectares in 1960 to 3 million hectares in 1990 (Hanak Freud et al. 2000). Yet, in the forest-savannah transition zone in central Cameroon, which is the main cocoa producing area of the country, cocoa trees are, on the contrary, playing a major forestation role in a region that is considered to be sub-optimum for cocoa growing due to the ecological constraints exerted on the crop (Wood and Lass, 1985). The existence of cocoa agroforests established on the grasslands of the forest-savannah transition zone in central Cameroon incites one to reflect upon the processes whereby this original cocoa growing system, which differs considerably from the usual cocoa growing development scheme, came about and functions. (Resume d'auteur)
Agroforestry systems (AFS) are multi-species systems comprising cropped and associated spontaneou... more Agroforestry systems (AFS) are multi-species systems comprising cropped and associated spontaneous species, including trees. The species in AFS provide different levels of regulating, supporting and provisioning ecosystems services (ES). We assume that the provision of ES depends on the functional characteristics of all associated species and their spatial layout in the AFS, which we call here the “functional motif”. We propose the concept of Ecosystem Service Functional Motif (ESFM) defined as the smallest spatial unit that is relevant to understand the provision of all the targeted ES, at a given time. This ESFM is useful to determine the smallest scale at which data should be collected for relevant upscaling of AFS functioning. As a proof of the ESFM concept, we use it to describe existing AFS covering a wide range of species richness X spatial organisation. We show, for each AFS, the ESFM for various types of targeted (multiple) ES at various stages in the development of the sys...
Agroforestry Systems, 2010
In Cameroon, cocoa trees are mostly grown in forests and without fertilization. Our aim was to le... more In Cameroon, cocoa trees are mostly grown in forests and without fertilization. Our aim was to learn more about the temporal dynamics of soils in cocoa agroforests by comparing young (1–4 years old) and old (over 25 years old) cocoa agroforests. Short fallow and secondary forest were used as treeless and forest references. The numbers and diversities of soil vesicular arbuscular mycorrhizal
Perspective
La agroforestería, que asocia árboles con cacaoteros, parece ser una opción posible para renovar ... more La agroforestería, que asocia árboles con cacaoteros, parece ser una opción posible para renovar el cultivo del cacao en África. El cultivo puro de árboles de cacao, dominante, no es sostenible y el potencial productivo disminuye con el tiempo. Por lo tanto, es urgente encontrar soluciones técnicas que estabilicen las áreas de cultivo de cacao, reduzcan la presión sobre los bosques y se adapten al cambio climático. Se puede encontrar un equilibrio entre los árboles de cacao y una mezcla de árboles escogidos por los agricultores para sus diversos usos, manteniendo al mismo tiempo un rendimiento de cacao adecuado a largo plazo. Este equilibrio también asegura servicios ecológicos como el almacenamiento de carbono y la protección fitosanitaria. Un trabajo reciente llevado a cabo en Camerún muestra que el manejo de las plantaciones de cacao agroforestales puede basarse en un indicador simple, la medición del área basal de los árboles de cacao y la de los árboles asociados. Este indicado...
Agronomy for Sustainable Development
In order to cope with current challenges facing world cocoa production and the obvious lack of su... more In order to cope with current challenges facing world cocoa production and the obvious lack of sustainability of the intensive model proposed to farmers, more ecologically efficient cocoa cropping systems must be developed, based in particular on a higher cultivated biodiversity level. The performances of cocoa multispecies systems, which involve multiple and hard to quantify interactions, are, however, more complicated to assess than that of monospecies systems. Despite this hurdle, we carried out a study in 48 cocoa agroforests located in three zones in central Cameroon where we conducted an analysis of cocoa yield components and agroforestry system structural characteristics that are likely responsible for observed yield variations. For the first time, we adapted the regional agronomic diagnosis method to demonstrate that the basal area per cocoa tree (mean 61.6 cm 2) and the unproductive adult cocoa tree rate (mean 21%) are key factors when assessing the productive performance of the surveyed systems whose average cocoa yield was 737 kg ha −1. From a methodological standpoint, the assessment approach we set up succeeded to overcome the specific obstacles linked with the features of agroforestry systems, especially their complexity (number of species and heterogeneity), by (i) determining relevant indicators and easily measurable variables, (ii) considering the associated tree communities as an environmental component, and (iii) analyzing interactions between cocoa stands and associated tree communities. From an operational standpoint, we showed that farmers can intervene on the structural characteristics of their cocoa agroforests to improve cocoa yields, in particular by eliminating unproductive cocoa trees whose basal area is less than 19 cm 2 to enable the other ones to grow.
European Journal of Agronomy
Experimental Agriculture
SUMMARY In Côte d'Ivoire, the world's largest cocoa producer, cacao (Theobroma cacao L.) ... more SUMMARY In Côte d'Ivoire, the world's largest cocoa producer, cacao (Theobroma cacao L.) is usually grown from seed. The genetics consist of a mix of amelonado, trinitario and selected hybrids. This mix of varieties generates high phenotypic variabilities, including variability in tree productivity, within cacao populations in both smallholder and industrial plantations. Tree-to-tree variability in yield has been reported in cacao breeding trials under different environmental conditions. However, it has never been considered a limiting factor for agronomical performance of seedling-based cacao plantations. Around 10 000 cacao trees from seven plots under different environmental conditions in a cacao plantation in Côte d'Ivoire were monitored for 2 years. Pod production of individual trees was recorded and annual average tree pod yields were assessed. High heterogeneity in cacao-tree yields was observed in all plots, with coefficients of variation ranging from 56 to 102%....
Sustainable Development and Tropical Agri-chains, 2017
Agroforestry Systems, 2017
Plantations Recherche Developpement, 1996
Agroforestry Systems, 2010
In Cameroon, cocoa trees are mostly grown in forests and without fertilization. Our aim was to le... more In Cameroon, cocoa trees are mostly grown in forests and without fertilization. Our aim was to learn more about the temporal dynamics of soils in cocoa agroforests by comparing young (1-4 years old) and old (over 25 years old) cocoa agroforests. Short fallow and secondary forest were used as treeless and forest references. The numbers and diversities of soil vesicular arbuscular mycorrhizal (VAM) fungi on 60 cocoa producing farms in the Central province of Cameroon were assessed based on the classical morphotyping of spore morphology. We also observed the soil organic matter, nitrogen and major soil nutrients. VAM spore density was significantly lower in the young cocoa agroforests (16 spores g-1 dry soil) than in the old cocoa agroforests (36 spores g-1 dry soil). Levels in the nearby secondary forest (46 spores g-1 dry soil) were not significantly different from old cocoa. The spore density was significantly highest in the short fallow (98 spores g-1 dry soil). The Shannon-Weaver index also showed significantly lower biodiversity in young cocoa (0.39) than in old cocoa agroforests (0.48), secondary forest (0.49) and short fallow (0.47). These observations were supported by significant differences in the C:N ratio, Ca, Mg, and cation exchange capacity between young and old cocoa agroforests. We concluded that unfertilized cocoa agroforests could be sustainable, despite a decrease in some soil characteristics at a young stage, due to traditional land-conversion practices based on selective clearing and burning of secondary forest.
Perspective
Combining mixed trees with cocoa trees in so-called cocoa agroforestry systems is emerging as a v... more Combining mixed trees with cocoa trees in so-called cocoa agroforestry systems is emerging as a viable option for regenerating cocoa cropping in Africa. Pure cocoa crop stands currently prevail in these areas but are running out of steam. Technical solutions are therefore urgently needed to stabilize cocoa-growing areas, reduce pressure on forests and adapt to climate change. A balance can be struck in stands by combining cocoa trees with diverse trees chosen by farmers for their different uses, while maintaining a suitable and sustainable cocoa yield. Ecological services such as carbon storage and crop protection are co-benefits of this balance. Recent research in Cameroon highlights that cocoa agroforestry stands can be managed using a straightforward indicator—measurement of the basal area of cocoa trees and associated trees. This indicator could be adopted for sustainable cocoa production certification purposes, while the observed convergence between local know-how and scientifi...
Perspective
L’agroforesterie, qui associe des arbres aux cacaoyers, apparaît comme une option crédible pour r... more L’agroforesterie, qui associe des arbres aux cacaoyers, apparaît comme une option crédible pour renouveler la cacaoculture en Afrique. La culture pure de cacaoyers, dominante, y est en effet à bout de souffle. Il est donc urgent d’identifier des solutions techniques pour stabiliser les zones cacaoyères, réduire la tension sur les forêts et s’adapter à l’évolution du climat. Un équilibre peut être trouvé entre les cacaoyers et un panachage d’arbres choisis par les agriculteurs pour leurs usages variés, tout en maintenant un rendement en cacao convenable sur le long terme. Cet équilibre assure aussi des services écologiques comme le stockage du carbone et la protection phytosanitaire. Des travaux récents menés au Cameroun montrent que le pilotage des cacaoyères agroforestières peut s’appuyer sur un indicateur simple, la mesure de la surface terrière des cacaoyers et celle des arbres associés. Cet indicateur pourrait être adopté pour la certification du cacao durable, tandis que la con...
Http Www Theses Fr, Jun 17, 2011
La mise en place à la plantation d'un ombrage provisoire associé à quelques arbres de forêt (ombr... more La mise en place à la plantation d'un ombrage provisoire associé à quelques arbres de forêt (ombrage permanent) et la maîtrise de la végétation adventice sont deux techniques culturales indispensables pour réussir la replantation des vieilles cacaoyères au Togo. Cette réussite est cependant conditionnée par la pédogenèse des sols occupés par les vieilles plantations.
Cocoa (Theobroma cacao L.) growing is traditionally practised after forest clearance and is gener... more Cocoa (Theobroma cacao L.) growing is traditionally practised after forest clearance and is generally considered to be one of the main deforestation factors in the tropics, as in Ivory Coast, where the forest area declined from 13 million hectares in 1960 to 3 million hectares in 1990 (Hanak Freud et al. 2000). Yet, in the forest-savannah transition zone in central Cameroon, which is the main cocoa producing area of the country, cocoa trees are, on the contrary, playing a major forestation role in a region that is considered to be sub-optimum for cocoa growing due to the ecological constraints exerted on the crop (Wood and Lass, 1985). The existence of cocoa agroforests established on the grasslands of the forest-savannah transition zone in central Cameroon incites one to reflect upon the processes whereby this original cocoa growing system, which differs considerably from the usual cocoa growing development scheme, came about and functions. (Resume d'auteur)
Agroforestry systems (AFS) are multi-species systems comprising cropped and associated spontaneou... more Agroforestry systems (AFS) are multi-species systems comprising cropped and associated spontaneous species, including trees. The species in AFS provide different levels of regulating, supporting and provisioning ecosystems services (ES). We assume that the provision of ES depends on the functional characteristics of all associated species and their spatial layout in the AFS, which we call here the “functional motif”. We propose the concept of Ecosystem Service Functional Motif (ESFM) defined as the smallest spatial unit that is relevant to understand the provision of all the targeted ES, at a given time. This ESFM is useful to determine the smallest scale at which data should be collected for relevant upscaling of AFS functioning. As a proof of the ESFM concept, we use it to describe existing AFS covering a wide range of species richness X spatial organisation. We show, for each AFS, the ESFM for various types of targeted (multiple) ES at various stages in the development of the sys...
Agroforestry Systems, 2010
In Cameroon, cocoa trees are mostly grown in forests and without fertilization. Our aim was to le... more In Cameroon, cocoa trees are mostly grown in forests and without fertilization. Our aim was to learn more about the temporal dynamics of soils in cocoa agroforests by comparing young (1–4 years old) and old (over 25 years old) cocoa agroforests. Short fallow and secondary forest were used as treeless and forest references. The numbers and diversities of soil vesicular arbuscular mycorrhizal
Perspective
La agroforestería, que asocia árboles con cacaoteros, parece ser una opción posible para renovar ... more La agroforestería, que asocia árboles con cacaoteros, parece ser una opción posible para renovar el cultivo del cacao en África. El cultivo puro de árboles de cacao, dominante, no es sostenible y el potencial productivo disminuye con el tiempo. Por lo tanto, es urgente encontrar soluciones técnicas que estabilicen las áreas de cultivo de cacao, reduzcan la presión sobre los bosques y se adapten al cambio climático. Se puede encontrar un equilibrio entre los árboles de cacao y una mezcla de árboles escogidos por los agricultores para sus diversos usos, manteniendo al mismo tiempo un rendimiento de cacao adecuado a largo plazo. Este equilibrio también asegura servicios ecológicos como el almacenamiento de carbono y la protección fitosanitaria. Un trabajo reciente llevado a cabo en Camerún muestra que el manejo de las plantaciones de cacao agroforestales puede basarse en un indicador simple, la medición del área basal de los árboles de cacao y la de los árboles asociados. Este indicado...
Agronomy for Sustainable Development
In order to cope with current challenges facing world cocoa production and the obvious lack of su... more In order to cope with current challenges facing world cocoa production and the obvious lack of sustainability of the intensive model proposed to farmers, more ecologically efficient cocoa cropping systems must be developed, based in particular on a higher cultivated biodiversity level. The performances of cocoa multispecies systems, which involve multiple and hard to quantify interactions, are, however, more complicated to assess than that of monospecies systems. Despite this hurdle, we carried out a study in 48 cocoa agroforests located in three zones in central Cameroon where we conducted an analysis of cocoa yield components and agroforestry system structural characteristics that are likely responsible for observed yield variations. For the first time, we adapted the regional agronomic diagnosis method to demonstrate that the basal area per cocoa tree (mean 61.6 cm 2) and the unproductive adult cocoa tree rate (mean 21%) are key factors when assessing the productive performance of the surveyed systems whose average cocoa yield was 737 kg ha −1. From a methodological standpoint, the assessment approach we set up succeeded to overcome the specific obstacles linked with the features of agroforestry systems, especially their complexity (number of species and heterogeneity), by (i) determining relevant indicators and easily measurable variables, (ii) considering the associated tree communities as an environmental component, and (iii) analyzing interactions between cocoa stands and associated tree communities. From an operational standpoint, we showed that farmers can intervene on the structural characteristics of their cocoa agroforests to improve cocoa yields, in particular by eliminating unproductive cocoa trees whose basal area is less than 19 cm 2 to enable the other ones to grow.
European Journal of Agronomy
Experimental Agriculture
SUMMARY In Côte d'Ivoire, the world's largest cocoa producer, cacao (Theobroma cacao L.) ... more SUMMARY In Côte d'Ivoire, the world's largest cocoa producer, cacao (Theobroma cacao L.) is usually grown from seed. The genetics consist of a mix of amelonado, trinitario and selected hybrids. This mix of varieties generates high phenotypic variabilities, including variability in tree productivity, within cacao populations in both smallholder and industrial plantations. Tree-to-tree variability in yield has been reported in cacao breeding trials under different environmental conditions. However, it has never been considered a limiting factor for agronomical performance of seedling-based cacao plantations. Around 10 000 cacao trees from seven plots under different environmental conditions in a cacao plantation in Côte d'Ivoire were monitored for 2 years. Pod production of individual trees was recorded and annual average tree pod yields were assessed. High heterogeneity in cacao-tree yields was observed in all plots, with coefficients of variation ranging from 56 to 102%....
Sustainable Development and Tropical Agri-chains, 2017
Agroforestry Systems, 2017
Plantations Recherche Developpement, 1996
Agroforestry Systems, 2010
In Cameroon, cocoa trees are mostly grown in forests and without fertilization. Our aim was to le... more In Cameroon, cocoa trees are mostly grown in forests and without fertilization. Our aim was to learn more about the temporal dynamics of soils in cocoa agroforests by comparing young (1-4 years old) and old (over 25 years old) cocoa agroforests. Short fallow and secondary forest were used as treeless and forest references. The numbers and diversities of soil vesicular arbuscular mycorrhizal (VAM) fungi on 60 cocoa producing farms in the Central province of Cameroon were assessed based on the classical morphotyping of spore morphology. We also observed the soil organic matter, nitrogen and major soil nutrients. VAM spore density was significantly lower in the young cocoa agroforests (16 spores g-1 dry soil) than in the old cocoa agroforests (36 spores g-1 dry soil). Levels in the nearby secondary forest (46 spores g-1 dry soil) were not significantly different from old cocoa. The spore density was significantly highest in the short fallow (98 spores g-1 dry soil). The Shannon-Weaver index also showed significantly lower biodiversity in young cocoa (0.39) than in old cocoa agroforests (0.48), secondary forest (0.49) and short fallow (0.47). These observations were supported by significant differences in the C:N ratio, Ca, Mg, and cation exchange capacity between young and old cocoa agroforests. We concluded that unfertilized cocoa agroforests could be sustainable, despite a decrease in some soil characteristics at a young stage, due to traditional land-conversion practices based on selective clearing and burning of secondary forest.
Perspective
Combining mixed trees with cocoa trees in so-called cocoa agroforestry systems is emerging as a v... more Combining mixed trees with cocoa trees in so-called cocoa agroforestry systems is emerging as a viable option for regenerating cocoa cropping in Africa. Pure cocoa crop stands currently prevail in these areas but are running out of steam. Technical solutions are therefore urgently needed to stabilize cocoa-growing areas, reduce pressure on forests and adapt to climate change. A balance can be struck in stands by combining cocoa trees with diverse trees chosen by farmers for their different uses, while maintaining a suitable and sustainable cocoa yield. Ecological services such as carbon storage and crop protection are co-benefits of this balance. Recent research in Cameroon highlights that cocoa agroforestry stands can be managed using a straightforward indicator—measurement of the basal area of cocoa trees and associated trees. This indicator could be adopted for sustainable cocoa production certification purposes, while the observed convergence between local know-how and scientifi...
Perspective
L’agroforesterie, qui associe des arbres aux cacaoyers, apparaît comme une option crédible pour r... more L’agroforesterie, qui associe des arbres aux cacaoyers, apparaît comme une option crédible pour renouveler la cacaoculture en Afrique. La culture pure de cacaoyers, dominante, y est en effet à bout de souffle. Il est donc urgent d’identifier des solutions techniques pour stabiliser les zones cacaoyères, réduire la tension sur les forêts et s’adapter à l’évolution du climat. Un équilibre peut être trouvé entre les cacaoyers et un panachage d’arbres choisis par les agriculteurs pour leurs usages variés, tout en maintenant un rendement en cacao convenable sur le long terme. Cet équilibre assure aussi des services écologiques comme le stockage du carbone et la protection phytosanitaire. Des travaux récents menés au Cameroun montrent que le pilotage des cacaoyères agroforestières peut s’appuyer sur un indicateur simple, la mesure de la surface terrière des cacaoyers et celle des arbres associés. Cet indicateur pourrait être adopté pour la certification du cacao durable, tandis que la con...
Http Www Theses Fr, Jun 17, 2011
La mise en place à la plantation d'un ombrage provisoire associé à quelques arbres de forêt (ombr... more La mise en place à la plantation d'un ombrage provisoire associé à quelques arbres de forêt (ombrage permanent) et la maîtrise de la végétation adventice sont deux techniques culturales indispensables pour réussir la replantation des vieilles cacaoyères au Togo. Cette réussite est cependant conditionnée par la pédogenèse des sols occupés par les vieilles plantations.