The objective of this Action was to enhance knowledge, methodology and models of rhizosphere processes. Emphasis was on dynamic feedback loops between plants and soil in natural, agricultural and forest ecosystems, including contaminated ones. This Action focused on collecting, evaluating and categorizing the available, scattered data on rhizosphere processes and building a joint European database. Methods for rhizosphere research, and for solving key scaling problems, were compared, evaluated, categorized and harmonized. The Action fostered the development of new methodologies, including molecular biology-based ones, to study rhizosphere processes with emphasis on in situ approaches. Areas for further research relating to rhizosphere processes, which could benefit from a European approach, were identified. Processes operating in the rhisosphere, which are very sensitive to environmental changes caused by the pollution, are better understood due to the Action’s efforts. The database of models has successfully gathered published models relevant to rhizosphere research. A major effort has been made to identify multi-component models that adequately incorporate all possible rhizosphere interactions, at the scale of a single root. This was the focus of a multi-authored publication in Plant and Soil. The Handbook of Methods in Rhizosphere Research is another achievement of the Action, gathering a total of 240 method sheets that are relevant to the specific properties and scale of the rhizosphere. No such book has ever been published, to the best of our knowledge. This unique compilation shall be useful for the entire community of scientists working on the rhizosphere, and particularly for new comers in this domain. Another major success was the organisation of a Training School on the Modeling of Rhizosphere Processes in 2005.The International Conference RHIZOSPHERE 2004 held in Munich was another key success of COST Action 631 – which played a key role in the organisation of this event, attended by 480 participants.
