Greenhouse engineering: New technologies and approaches

Firstly, this article discusses the greenhouse engineering situation in three geographic areas which are relevant in the field of protected cultivation: Northern Asia, The Netherlands and the Mediterranean. For each area, the prevailing greenhouse type and equipment is briefly described. Secondly, the main technological constraints are pointed out and finally the research directions are discussed. For all areas under consideration, attempts to design more efficient greenhouse systems are under way. In Northern Asia progress is being made towards the optimisation of greenhouses as a solar collector and to the development of new heating strategies. Important subjects addressed in The Netherlands are energy conservation and the replacement or alleviation of human labour by increasing mechanisation. In the Mediterranean there is growing interest in semi-closed greenhouses with CO2 enrichment and control of excessive humidity. All geographic areas share the need of having an optimised climate control based on the crop response to the greenhouse environment. All areas also share the requirement of being respectful to the environment, therefore future greenhouses are expected to use engineering to produce with minimal or zero emissions.