“Increase the number of mechanical tractors adapted to Angolan conditions”, says Kristina Rusarova from the Czech University of Life Sciences. Her premise is that technology can increase agricultural production in the Day 3 session on Product Quality and Processing. Meanwhile, Birgit Jankowsky from the University of Hohenheim argues that the use of “Hohenheim tunnel drier” to dry Peruvian fresh “chillies” is more hygienic, more protected from rain and dust, lesser carotenoid degradation. In addition, it need a shorter drying time compared to the traditional direct ground drying often practiced among smallholder chilli farmers in the Peruvian coast. Lastly, Franz Roman from the University of Kassel developed and experimented a more efficient flat bed dryer used to dry paddy, cocoa and other agricultural products in tropical countries. In addition, He believes that this technology can solve the problem of uneven distribution of airways that often affects the efficient performance of similar technologies. But the question remains, how can this technology be implemented to tropical countries that are presently utilizing less efficient drying technologies?

An Interview with Prof. Dr. Rattan Lal “You cannot continue taking money out from the bank without putting it back. So improvement of soil on the basis of what has been taken out from harvesting must be replaced in a scientific manner,” stressed Prof. Dr. Rattan Lal, a distinguished university professor in soil physics and tropical soils from Ohio State University. Either chemically or organically “Applying manure or using bio-soil is the best option, but sometimes it is not strategically a very good option because manure requires a bulk amount. We require 10 ton/hectare of manure, which is the equivalent to100 kg of chemical fertilizer. So sometimes it is a question of logistics” he added. “A judicious combination of both organic and inorganic fertilizers is required because many times the organic matter is not adequate – it is called integrated nutrient management.” Sub Saharan soils are marginalized “I think Africa is the continent where the green revolution has by-passed because the soils in Sub Saharan Africa are really marginalized. They are depleted, denuded and degraded. Soil erosion and nutrient depletion of soil organic matter content have been very serious problems in Sub Saharan Africa. For sustainability, soil quality must be improved,” he concluded.

Huge investments are made to understand the factors motivating farmers to adopt new agricultural technologies. Smallholders are hesitant to implement innovative methods like improved seeds, new varieties etc. Their decisions are influenced by natural, human, physical, social and financial considerations. Thomas Miethbauer and Guy Hareau conducted a study costing 200,000$ to understand Participatory Plant Breeding (PPB) among marginal potato farmers in Peru. The results from the study indicated that there must be an incorporation of the perception of farmer preferences and attitudes in research design, testing and diffusion. The involvement of farmers in terms of their requirements and expectations has to be merged in the development of any new agronomic expertise to make it work. The Role of Social Networking

Tropentag, a conference of which participants are carrying tons of information in their heads. A very little amount of this information is presented in posters and shared in 10-minute oral presentations. What is the meaning beyond all this academic research and how does it contribute to the real life? And even further, how can the information gathered inside the walls of the University of Bonn for 3 days be used and understood in the world outside? “These are the questions we should ask from ourselves all the time,” Dr. Carla Roncoli from the Emory University says. According to Dr. Roncoli, there are two kinds of science and scientists. First, there are the academic scientists, more concentrating on the science itself. The questions that drive the main journals are not always the ones that contribute to the real world, though. These scientists often end up for example to teach in the Universities. In my head this means that they continue to live in the scientific world. Then there are the ones contributing more to the real world. Dr. Roncoli sees herself as a representative of this category, the category with more social aspect. Neither one of these two categories, Dr. Roncoli says, is better than the other. Valuable research is made within both of them, and researchers come up with important results and raise new questions. Dr. Roncoli herself has done interdisciplinary research and appreciates the different ways of learning and understanding things.

An interview with Carla Roncoli. When bringing new ideas of agricultural practices to the local level, many highlight the value of local knowledge. The willingness to adapt to new practices, and the farmers’ ability to choose in limited situations when decision-making is economically, politically and culturally embedded, are much discussed. Are the farmers the real agents of their own lives, or subordinates of the political and economical structures? How about the fight of local knowledge versus the praised scientific information and technical innovations of the global North? Farmers do have the ability to be relatively flexible, though commercial agriculture may set the farmers in a more vulnerable position, states Dr. Carla Roncoli from the Emory University. As an example, Dr. Roncoli mentions how concentrating on one or two cash crops, instead of previously practised diverse agriculture, sets the farmers on a higher risk. This happened to the farmers in Burkina Faso when theybegan to concentrate on cotton production. It is a dominating system demanding commitment from the farmer, thus reducing the flexibility of the farmer for choosing alternatives when the resources are scarce.

The tropics are home to the largest share of the world's biodiversity. At the same time, they are regions where persistent poverty, population increase and climate change pose major threats to the food security of the local populations. Therefore, there are in great need of sustainable modes of land-use, which maintain diversity at all levels. This is achieved at best through multi-crop prodction systems, hence forests and agroforestry could not be missing from the international discourse for development on the margin. This year's Tropentag covered the topic through numerous posters and oral presentations, with interesting contributions from both theory and practice. Julia Szulecka from the Technische Universität Dresden, traced the development of historically changing assumptions, concepts, values and practices that constitute our way of viewing plantation forestry. By doing so, she drew a direct correlation between the evolution of meanings and associations related to forest plantations and the development of plantation-related policies. Julia Szulecka, Technische Universität Dresden

Nowadays, discussions about climate change are almost a guaranteed part of any scientific or academic forum. Tropentag 2011 is no exception. It is not only that climate change had one thematic session and two posters sessions dedicated to it, but the topic was constantly mentioned in other sessions such as Food Security, Ecosystem Services, Soil Fertility, Crop Production, Water and Irrigation, and Forests. I am not implying that climate change is THE ISSUE, but it seems clear that it was one of the key issues connecting the theme of marginality. If you follow the “whereabouts” of climate change (as I do!), you won’t be surprise to hear that nothing really new came out the Tropentag 2011. Don’t get me wrong, there were lots of useful new data, nice climatic models, experimental results and adaptation activities; but they were in most cases, an improved version of what we saw in previous gatherings dealing with the issue -nothing really new-. Where the heat comes from? I was actually surprised to see that during the thematic session, the large lecture room was overflowing with people. It was probably the most attended session apart from the plenary session on Wednesday 6 October, clearly indicating that visitors to Tropentag 2011 considered climate change as one of the hottest issues at the conference.

First of all, not all the agriculture takes place in rural areas. For example, Afton Halloran of the University of Copenhagen says that in the city of Dar es Salaam in Tanzania, approximately 40% of the population is formally or informally involved in urban agricultural practices. In the context of the ongoing urbanization in developing countries, rapidly growing cities raise a lot of problems that need solving. Johannes Schlesinger along with his other colleagues from University of Freiburg and Rhodes University have researched the impacts of urbanisation on livelihoods in African mid-sized towns, with a special focus on the impact of natural resources. They researched which part of income was produced through agricultural practices and whether the households profited of time and spatial changes. Starting with the fact that agricultural practices do play their role in terms of earning income, and that they increase in frequency the further you go from the city centre, Schlesinger et al. found that the peri-urban areas are the most dynamic in terms changes: They are where conflicts and transformations take place. Local and larger scale programme policies are thus needed to reduce livelihood vulnerability and to secure food- and land security. The problem is, that when asking the decision-makers in the rapidly growing African cities about the agricultural practices, they answer that there are none. Thus, the very first step for town planning in developing countries would be to realize the importance of agricultural practices in them, Schlesinger emphasizes.