Crop rotation and fertilization effects on weeds in rice based cropping systems in Madagascar

In the Mid-West region of Madagascar, yields in upland rice remain low due to both low soil fertility and high weed pressure in fields. Increasing managed biodiversity inside crop rotation may be an option to reduce weed pressure in cropping systems. The effect of managed biodiversity was studied in a field experiment carried out in Ivory (19°33'18.90"S, 46°24'53.08"E), with a randomized block design with four replications during two years. Three rainfed rice based rotations (Rice // Groundnut = RA, Rice // Sorghum + Vigna unguiculata =RSV, Rice//Mucuna cochinchinensis + Crotalaria spectabilis = RMC) combined with two levels of fertilization (Low Fertilization = manure vs. High Fertilization = manure + fertilizer) were compared to a rainfed rice monoculture. Each crop or crop mixture in the rotation was grown every year on plots measuring 45.9 m². Each year, weed and rice biomass were measured at each weeding date. Rice biomass was also measured at flowering and harvest. Rice yield and its components were measured at harvest. Weed flora was observed the second year to analyse potential change in weed communities according to fertilization and/or crop rotation. The first year, weed biomass and rice yield were higher in highly fertilized treatments than in lowly ones. In highly fertilized treatments, weeds did not affect yield and weed biomass was positively correlated to rice yield. On contrary, fertilization had no effect on weed biomass the second year. The highest and lowest weed biomass were observed on RA and RMC treatments respectively. Lowest rice yields were observed in RSV and RA treatments, in highly and lowly fertilized treatments respectively. In lowly fertilized treatments, weed biomass reduces significantly rice yield. Finally, rotation had more impact than fertilization on weed flora. Biodiversity may have positive effect on cropping systems performances but it depends largely on the introduced species

WIKWIO Portal: An online resource on weeds for sugarcane growers

Efficient control of weeds is only achievable through a clear and sound knowledge of their biology and ecology. The Weed Identification and Knowledge in the Western Indian Ocean (WIKWIO) portal (http://portal.wikwio.org/) has been developed to meet this objective. It aims at building and leveraging a science and technology network to consolidate existing scientific and technical knowledge, and facilitating the sharing of new information. Although the portal currently covers the Indian Ocean region, most of the tropical weeds that are documented are also present in many other sugarcane-producing countries. This paper highlights the benefits that this resource can have to growers for managing weeds in their fields. The WIKWIO portal is the outcome of a three-year collaboration among weed scientists of CIRAD (France), CNDRS (Comoros), FOFIFA (Madagascar), IFP (India) and MSIRI (Mauritius). A community of stakeholders involved in weed knowledge and management, also collaborated in the action. Experts from the six research institutions worked on a list of nearly 470 species of tropical weeds. They compiled and validated information on the biology, ecology, distribution, agronomic importance and management of each weed species in datasheets in both English and French. Each weed has been fully illustrated with high- resolution pictures and scanned herbarium sheets to provide additional details. Botanists and computer engineers set up an information system to host these data, in addition to other tools that facilitate rapid weed recognition and documentation. The portal became operational in early 2014 and was improved with various options at the completion of the project in February 2017. More than 750 users have registered on the WIKWIO network, contributing over 10,000 observations of weeds, many of them encountered in sugarcane fields in various parts of the world. All the observations posted on the website are geo-referenced, thus providing useful data on their ecological distribution. Identified species are linked to the appropriate datasheets, giving insights into their management and control. Weed identification is possible via a computer-aided tool (IDAO) available on the portal. This resource and the possibility of uploading observations onto the network are accessible through applications (apps) on mobile devices enabling easy use in the field for rapid weed control decision and intervention. The WIKWIO portal enhances a collaborative and participative approach by sharing knowledge and providing practical information. It can serve as a platform for establishing and reinforcing a community of sugarcane growers seeking help or exchanging experience on weed management issues. Nowadays, with the easy and rapid access to internet connectivity, timely assistance may be obtained through the portal. The latter takes place in a 'numerical agriculture' approach that is expected to evolve into a website for tropical weeds

Enjeux et contraintes du partage et de la diffusion des connaissances en malherbologie tropicale pour une meilleure gestion des enherbements, exemple du portail collaboratif Wiktrop

La production agricole tropicale est en pleine mutation et la gestion des enherbements est un élément majeur de la stratégie de l'agriculteur. L'élaboration d'itinéraires de gestion des adventices requiert de plus en plus de connaissances, sur la biologie des espèces, leur comportement dans les milieux cultivés et l'efficacité des pratiques de désherbage. L'accès à l'information est maintenant facilité par les infrastructures numériques en constante évolution, mais nécessite que la connaissance soit partagée, mise à jour et diffusée de façon continue. Une part de connaissance est présente chez chacun des acteurs (producteurs, vulgarisateurs, chercheurs, enseignants), mais sa compilation et sa diffusion présentent différentes contraintes d'ordre réglementaire, humain et technologique. Le portail collaboratif WIKTROP permet à tous les acteurs du monde agricole tropical de partager et diffuser leurs connaissances et leurs questionnements sur les adventices tropicales et leur gestion. Il est associé à des applications mobiles facilitant son utilisation au bureau, sur le terrain ou pour des formations

Improving management of weeds through a combination of participatory approach using citizen science and ICT tools

A significant challenge to agricultural productivity is weed management. This is particularly impor-tant in tropical areas where weeds can cause at least 20% loss in the productivity of food and cash crops. To help stakeholders of the Western Indian Ocean in improving weed management, the WIK-WIO (Weed Identification and Knowledge in the Western Indian Ocean) project has developed a par-ticular combination of scientific approach and ICT tools. This project is a EU-ACP Science & Technology II program-funded action. The WIKWIO initiative contributes to the establishment and strengthening of a community of stake-holders from research, education, extension and production around integrated weed management, by promoting knowledge sharing and collaboration. The action is aimed at enhancing capacities through an interdisciplinary and participatory approach, by building an ICT knowledge base of major weeds of food and cash cropping systems in the region. The approach consists in sharing data and knowledge among stakeholders, helping people in weed identification, and providing information on weeds and their management. All these aspects are made available through the web 2.0 participatory bilingual (Fr/En) WIKWIO portal, http://portal.wikwio.org. From this platform, any visitor can identify a weed with the IDAO module and get information on a specific weed and its management from the Species module. Several working group modules provide weed management information for different cropping systems. Portal-regis-tered members can provide knowledge on species and contribute to the species information DB, and also post field observations in order to contribute to weed distribution mapping. They can post obser-vations of unidentified weeds to request help from the community for identification and give informa-tion on its management. Scientific or technical documents can be shared on the portal. Members can comment on any piece of information present in the different modules of the portal. This comment can afterward become the starting point of a fruitful discussion. The WIKWIO portal is linked to a couple of free mobile applications available for Android and IOS systems. The application WIKWIO IDAO is dedicated to weed identification, while WIKWIO Citizen Science concerns the posting and browsing of observations in the field. After two years of work, the portal comprises a weed database of 350 species with a network of 466 reg-istered members involved in weed management in the Western Indian Ocean region. We expect to extend the area of interest of the portal to the Sub-Saharan African region with the collaboration of the FAO

Weed knowledge in Western Indian Ocean and Southern African region

Biodiversity information on weeds, covering species descriptions and distribution, is essential for understanding the ecology and distribution of weeds and their management. WIKWIO (Weed Identification and Knowledge in the Western Indian Ocean), a European Union's African Caribbean Pacific Science & Technology II programme funded project, is focused on the Western Indian Ocean region to develop species information systems on weeds in food and cash crops. Wikwio aims to assimilate weed knowledge through its participatory portal to strengthen a science and technology network of stakeholders such as scientists, extensionists and farmers in the African region. The portal platform has a Citizen Science module, a graphic driven species identification module, a species pages module conforming to Species Profile Model and a spatial module. Subscribing to open data paradigm, all the data on the portal is covered by Creative Commons license framework. Mobile applications for identifying 345 weed species and contributing to citizen science module are deployed. The poster will expose the portal features and related apps seeking participation from the stakeholders from the African region

Citizen science and expert community interactions using Wikwio, a week knowledge portal, focused on southern Africa

The Wikwio agricultural project aims to build a community of stakeholders including extension agents, students, farmers and scientists with a focus on weed species of food and cash crop systems in southern African region. Interactions between the citizen and scientific communities, facilitated by a technology platform is a promising approach. After almost three years in existence and steady growth, the platform hosts information on about 420 weed species with a community of around 650 members from 19 countries. A citizen science module on the Wikwio web platform enables people to contribute their observations about weeds. The module is interconnected with expert-curated species pages, spatial and documents modules that fosters interactions between citizen and scientific communities. These interactions improve the aggregation of scientifically validated data. For example, the citizen science module can inform scientists about the nature and level of occurrence of different weeds in different crop systems, their seasonality and distribution across the southern African region. In turn, the species pages module can inform extension agents and farmers about appropriate control measures for each species. Platform developers have built custom fields in the citizen science module to allow specific surveys to be commissioned by the scientific community. The comment stream in the same module can enable dialogue between the citizen and scientific communities allowing people to pose questions directly to experts to which experts can respond with additional details and clarifications. Active, wide and large-scale participation from diverse stakeholders in agricultural research and practice is building a vibrant Wikwio community around a facilitating technology platform and a shared scientific practice. (Texte intégral