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Publications

NIBIOs employees contribute to several hundred scientific articles and research reports every year. You can browse or search in our collection which contains references and links to these publications as well as other research and dissemination activities. The collection is continously updated with new and historical material.

2013

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Abstract

We provide a demonstration of the new tomographic profiling (TP) technique, here applied to forestry for the first time. The portable ground-based synthetic aperture radar (GB-SAR) system was used to capture profiles of the vertical polarimetric backscattering patterns through a 7 m tall stand of Norway spruce trees. The TP scheme collects data as for normal SAR imaging, but with the antennae aligned in the along-track direction. Adaptive post-processing meant that each TP scan simultaneously captured along-track image transects over the incidence angle range 0°–60°. An important feature of the derived image products is that incidence angle is constant at every point within an image. The measured HH–VV height backscatter profiles were very similar, whilst the cross-/co-polarization ratio showed very little variation with height through the stand. Backscattering profiles showed closest agreement with the branch biomass distribution through the canopy, rather than with trunk or branch + trunk biomasses. Equivalent interferometric tree heights were estimated from the centre of mass of the backscatter-height distribution, which displayed increasing height with increasing incidence angle. There was no significant vertical separation between the cross- and co-polarization returns.

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Abstract

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Abstract

Shifting from scientist-led top-down approaches in agricultural development to participatory approaches putting farmers and their knowledge in the center requires scientists and farmers to play new roles, changing social relationships between them, and among farmers themselves. Using mainly qualitative data and analysis, this paper reports social impacts (social relations, social empowerment and sharing of IPM information, and sustainability and institutionalization of IPM) for vegetable producers in an integrated pest management (IPM) project using farmer field schools (FFS) in Cotonou. Forty-three vegetable producers were chosen for semi-structured interviews. The project led to social empowerment of the vegetable producers and initiated a process of creation and sharing of IPM knowledge and building of social relations within and between the vegetable gardens. The participants realized they were sources of information for each other, and IPM knowledge was shared without the benefit or restriction of social networks. However, this study revealed several factors hindering the development of improved social relations among the vegetable producers and between these and the scientists and steering committee members, which in turn may result in lack of continuation and institutionalization of IPM activities. To overcome these obstacles, this research suggests that similar IPM-FFS projects encourage (1) a transparent selection process, (2) improvement of the Trainer of Trainers’ facilitation skills for better quality FFSs and improved sharing of complex information like agro-ecosystem analysis and beneficial insects, (3) building trust and confidence between the participants and scientists, (4) giving the ToT participants, community organizers and farmer organizations ownership of the project by giving them responsibility for creating post project plans to spread and institutionalize IPM of IPM-FFS activities and (5) facilitating the participants during and after the project in improving social relations and accountability. The results also draw lessons on how scientists and vegetable producers have or should have changed their roles to sustain and institutionalize IPM, such as the scientists and project leaders need to focus even more on their interactions with vegetable producers, enhancing their role as facilitators in initiating equitable processes of sustaining and institutionalizing IPM in the vegetable gardens.