Delineating the cropping area of cocoa agroforests is a major challenge in quantifying the contribution of land use expansion to tropical deforestation. Discriminating cocoa agroforests from tropical transition forests using multispectral optical images is difficult due to the similarity of the spectral characteristics of their canopies. Moreover, the frequent cloud cover in the tropics greatly impedes optical sensors. This study evaluated the potential of multiseason Sentinel-1 C-band synthetic aperture radar (SAR) imagery to discriminate cocoa agroforests from transition forests in a heterogeneous landscape in central Cameroon. We used an ensemble classifier, Random Forest (RF), to average the SAR image texture features of a grey level co-occurrence matrix (GLCM) across seasons. We then compared the classification performance with results from RapidEye optical data. Moreover, we assessed the performance of GLCM texture feature extraction at four different grey levels of quantization: 32 bits, 8 bits, 6 bits, and 4 bits. The classification’s overall accuracy (OA) from texture-based maps outperformed that from an optical image. The highest OA (88.8%) was recorded at the 6 bits grey level. This quantization level, in comparison to the initial 32 bits in the SAR images, reduced the class prediction error by 2.9%. The texture-based classification achieved an acceptable accuracy and revealed that cocoa agroforests have considerably fragmented the remnant transition forest patches. The Shannon entropy (H) or uncertainty provided a reliable validation of the class predictions and enabled inferences about discriminating inherently heterogeneous vegetation categories.
Tag: cocoa
Farmer management of cocoa agroforests in Cameroon: Impacts of decision scenarios on structure and biodiversity of indigenous tree species
Cocoa agroforests are dominant agricultural systems on the forest margins of Cameroon. Their management remains complex involving close interplay and trade-offs in social, ecological, economic and policy questions. To protect the cocoa crop and increase the net livelihood worth of cocoa agroforests, farmers maintain and or integrate diverse indigenous tree species in them. In a broadening context of environmental management these small holder, resource-poor farmers thus face important challenges in balancing livelihoods and conservation goals. This paper focuses on the characterization of cocoa agroforests on the forest margins of Cameroon in central Africa. It seeks to improve understanding of the complex relationships between livelihoods and cocoa agroforest land-use. It focuses on how farmer management decision scenarios can influence the architecture and indigenous trees biodiversity in cocoa agroforests. Methods used involved a rapid socio-economic survey, structural characterization and rapid biodiversity assessment of indigenous tree species in at least eight hectares of non contiguous cocoa agroforests. Descriptive statistics were used to analyze socio-economic and structural variables. Non parametric tests were used to evaluate changes in structural characteristics following management decision scenarios by farmers. Interpretation of results shows food security to be a major land use preoccupation of farmers. Due to revenue potential and high density of useful fruit and food trees cocoa systems can help slow down need for deforestation, maintain carbon and stabilize forest margins. Strata containing useful trees for food and fruits are most carefully managed and conserved in comparison with strata containing mainly medicinal and fuel wood trees. Despite species elimination scenario the basic proportionality and balance between bottom and upper stratums is maintained. Although overall species abundance reduces following eliminations, true diversity shows a slight positive change due probably to increased relative diversity of indigenous tree species. Summarily therefore, farmer management of cocoa systems appears undisruptive of both structure and biodiversity of indigenous trees.
Long-term dynamics of cocoa agroforestry systems established on lands previously occupied by savannah or forests
Cocoa agroforestry systems (cAFS) in Central Cameroon are established on lands which were either forest or savannah. The functioning and ecosystem services (ES) delivery of an agroecosystem can be influenced by past land-use. We hypothesised that savannah-derived cocoa agroforestry systems (S-cAFS) and forest-derived cocoa agroforestry systems (F-cAFS) would (i) progressively drift away from past land-use, and (ii) eventually converge and support comparable levels of ecosystem services. We selected 25 ecosystem attributes directly related to at least one of the following six ecosystem (dis)services (ES): species conservation, carbon storage, crop production, nutrient cycling, soil quality and soil pollution. We followed their temporal evolution in S- and F-cAFS along >70-year chronosequences. Our results showed that the attributes and services studied followed typical temporal trajectories in S- and F-cAFS while generally tending to reach comparable levels on the long run. However, the time needed to do so varied strongly and ranged from 20 to 30 years for perennial species diversity to more than 70 years for C storage or some components of soil quality. The results also demonstrated that S-cAFS could sustainably improve many of the studied attributes and ES. Regarding the attributes related to the cocoa stand, both S- and F-cAFS seemed influenced by their previous land-use up until 15 and 30 years, respectively, after their establishment. With respect to soil quality, nutrient cycling and carbon storage, only S-cAFS could be significantly distinguished from their past land-use, after 15 to 30 years.
Tree Seed and Seedling Supply and Distribution System in Uganda
In Uganda, the tree seed sector is largely centralized, limiting access by farmers to high quality seedlings due to distant supply locations. This has left suppy of most of the tree germplasm to the informal sector, characterized by road-side tree nurseries and seed dealers who have limited knowledge on seed sourcing and collection and seedling production. Through semi-structured and key informant interviews, a sample survey involving 73 smallholder tree seed collectors, processors and tree nursery operators, this study investigates the role of government, smallholder tree seed collectors, processors and suppliers, nursery operators and the private sector in Uganda’s tree seed and seedling production and supply system. The study also identifies constraints in the seed and seedlings distribution system in Uganda and suggests key policy and institutional reforms. The source of tree germplasm is found to be heavily influenced by ease of access. About 60%) of the germplasm is purchased by individual farmers for their own planting. Low quality seed, limited seed sources and overgrown seedlings remain key deficiencies in the tree seed sector. Potential business opportunities in the tree seed and seedling production and supply value chain are identified, including production and sale of high quality germplasm. These will enhance availability of tree germplasm of high quality to meet the growing need for afforestation and reforestation in Uganda.
Village centres to boost cocoa production
The World Agroforestry Centre (ICRAF) has, with other partners, set up the Vision for Change (V4C) project to boost production of cocoa. In the first phase of the project, 2010 to 2013, sixteen Cocoa Development Centre (CDCs) were set up by the project to demonstrate, on farmers’ fields, various recommended technologies for cocoa rehabilitation. Particularly impressive are grafted trees; within 12 months of grafting, new stems on old cocoa trees are producing large, healthy pods. ‘Total replanting’ trials established in 2010 now boast young trees with bright green leaves and characteristic auburn tops, their branches heavy with fruit. Through their role of uniting farmers with better seedlings and services, the 53 new CVC operators will be front and centre of this effort to raise cocoa productivity. More training of CVC operators is planned so the region gets covered.
Compatibility of Ten Elite Cocoa (Theobroma cacao L.) Clones
One way of boosting cocoa productivity which has plummeted over the last decade in Côte d’Ivoire is to introduce high performing clones. Preliminary observations have indicated that these new clones have differing growth patterns and agronomic traits in the field. Assessing their compatibility is of paramount importance since these clones will be made available to the farmers in the near future. This study was conducted in Soubré, southwest of Côte d’Ivoire, to evaluate the compatibility of ten new cocoa clones (coded as C1, C8, C9, C14, C15, C16, C17, C18, C20, and C21). A half diallel design consisting of 10 self-pollinations and 45 inter-crosses, replicated three times, was used. Results showed significant differences among clones for pollination success. Out of the ten clones evaluated, six (C1, C8, C9, C15, C17 and C21) were self-compatible. With a 39% mean pollination success, C9 was quite interesting because it has been reported to be among the highest yielding clones. Introduction of improved germplasm will go a long way towards enhancing productivity in Côte d’Ivoire, radically impact farmers’ livelihoods, and contribute significantly to a more reliable supply of cocoa beans for chocolate manufacturers.
A brighter future for cocoa farmers: how Vision for Change programme is raising productivity and improving rural livelihoods
This booklet tells the story of the Vision for Change (V4C) project. Supported by Mars Inc. and managed by the World Agroforestry Centre, the project seeks to improve the fortunes of Côte d’Ivoire’s cocoa sector. If the country is to retain its status as the world’s leading producer, radical measures are required to increase yields and improve the welfare of the 800,000 farmers who grow the crop. Many orchards are over 30 years old and their yields are a fraction of what they once were. Exhausted soils, poor agricultural practices and a lack of inputs have contributed to poor performance. As a result, many cocoa-growing communities suffer from high levels of poverty. The V4C project is tackling the problem in two ways: by rehabilitating cocoa orchards and by encouraging and supporting community development.
Farmers in Côte d’Ivoire value integrating tree diversity in cocoa for the provision of ecosystem services
Côte d’Ivoire produces 40 % of the world supply of cocoa but much of the plantation area is aging and declining in productivity, while opportunities for land expansion into new forest land are quickly disappearing. Rejuvenation strategies for cocoa presently coalesce either around improved varieties and greater use of agro-chemical inputs in full sun systems or eco-certification that requires trees to be integrated with cocoa. Here, we explore the possibility of uniting these approaches through building on current farmer practice of incorporating trees in their cocoa fields to improve cocoa productivity and diversify their livelihoods. We interviewed 355 farmers about trees integrated in their cocoa fields across four locations in the South-West of Côte d’Ivoire in 2012, stratified by whether or not farmers were eco-certified. Despite the massive deforestation, a rich diversity of trees was found in cocoa fields and an overwhelming majority of farmers (95 %) wanted more trees and/or more tree species, regardless of their certification status or ethnic origin. There was a consensus that most trees were compatible with cocoa, but farmers also traded off negative impacts of some species against their productive contribution to their livelihood. Farmers valued tree diversity on their cocoa plots and provided detailed information on how 32 tree species interacted with cocoa in terms of soil moisture retention, soil fertility improvement and pest and disease interactions but also had key gaps in knowledge about alternative hosts of mirids and mistletoe. The majority of farmers were not aware of the certification requirements for tree species and shade cover but a much higher proportion of certified farmers (76 %) had received information about shade trees than non-certified farmers (15 %), although advice only related to eight tree species. Scope for building on local knowledge and practice to sustainably increase cocoa productivity through promoting tree diversity while enhancing other ecosystem service provision was identified and the next steps required to realize this set out.
Ant-mediated ecosystem services and disservices on marketable yield in cocoa agroforestry systems
The impact of complex direct and indirect interactions between multiple functional groups on plants is poorly documented. In tropical agroecosystems, ants interact with crop mutualists and antagonists, however, little is known about effects of dominants ant community properties on the consequence of such cascading interactions which can be measured through final ecosystem service, crop yield. Here, we present a replicated ant fauna manipulation experiment in cocoa agroecosystems, where we used ant exclusion treatments to test the economic importance of the presence of ants, and two additional treatments where we experimentally introduced one of two common dominant ant species which allowed comparing their effects with those of the naturally occurring ant fauna. The proximate aim was to assess the impact of ants Crematogaster sp., Camponotus brutus Auguste-Henri Forel and Oecophylla longinoda Latreille on cacao yield, which is known to depend on several, cascading intermediate ecosystem services (e.g. control of specific pests). Ants provided ecosystem services in term of reduced pest damage caused by Salhbergella singularis Hagh (Hemiptera: Miridae) and Characoma stictigrapta Hmps (Lepidoptera: Noctuidae) but also disservices such as increased pathogen disease caused by Phyphthora megakarya Brasier and Griffin dissemination and indirectly enhanced damage of other pest species. Yields were highest in non-manipulated and species-rich ant communities, whereas ant exclusion and communities dominated by a single species decreased yield by more than 30%. Associated ant communities between dominant and non-dominant species resulted in the same yields as in non-manipulated controls. Dominant ant communities maximized the control of a particular pest species, but not cacao yield. We show a positive relationship between ant species rich communities and financial performance and we postulate that complex agroecosystems can offer competitive business opportunities for small-scale farmers, while contributing to biodiversity conservation. However, more interdisciplinary studies are needed to quantify financial and biodiversity performance opportunities to allow up-scaling of these findings. © 2017 Elsevier B.V.
Tea, Coffee, and Cocoa
Tea, coffee, and cocoa are cultivated for their young leaves, cherries, and beans, respectively, from which popular beverages are made and consumed worldwide. In addition to being used as beverage, cocoa is essentially consumed as chocolate confectionery products. The stimulant properties and medicinal values of these beverages are recognized since the ancient times. These crops are among the most important agricultural commodities worldwide. Tea is the most popular beverage, and it is consumed by 65% of the world’s population, while coffee ranks second with about 2 billion cups consumed daily. Nearly 4 kg cocoa bean equivalent is consumed per capita annually in developed countries. In 2012, the production of processed tea, green coffee, and cocoa beans was 4.8, 8.8, and 5.0 million MT, respectively. This production occurs largely in the developing world (with the exception of tea in China), while the consumption happens mainly in the developed economies. For each of these commodities, more than 50% of the production is in only three countries, but unlike other products such as crude oil the market price is regulated by consumption countries. The economy of many growing countries depends heavily on the earnings from these crops which support directly or indirectly millions of people in both producing and consuming countries.