Sustainable land use needs a manageable nexus of knowledge from planning practice, policy makers, the
private economy, and civic society, as well as from scientific research. This is mutually dependent on the
communicative and collaborative turn in spatial planning as well as by transdisciplinary research approaches.
This paper offers an approach how to organise knowledge management and co-production of knowledge in
the context of complex land use decisions. Therefore, a prototype of an internet-based knowledge platform
is introduced based on a theoretical reflection of concepts for integrated information and knowledge
management, as well as on practical experiences derived from a German case study. We conclude that
sustainable land use requires Planning Support Systems (PSS) that combine transdisciplinary perspectives
in order to co-produce robust knowledge. This also implies a transdisciplinary design of PSS. Challenges of
implementation are discussed and further research is specified.