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| Author: | A. Baille |
| Keywords: | Greenhouse, climate control, structure, ventilation, cooling |
Abstract:
Greenhouse crops in mild winter climates cannot be grown all year round and their yield does not fulfil the quality standards because of inadequate climatic conditions prevailing in the rudimentary shelters used as greenhouse.
In order to alleviate the strong heat load and consecutive plant stress during summer, it is necessary to improve greenhouse design and control of the inside climatic variables.
Technological solutions are presently available but are often considered, rightly or not, as too expensive by the growers.
Therefore, the basic problem can be defined as an optimisation one, i.e. how to find a compromise between the two extreme cases represented by the rudimentary shelters of mild-winter countries and the expensive high-tech glasshouses of North-Europe.
The first part of the paper addresses this issue and focuses on the knowledge and methodology necessary for finding this compromise.
The determination of the best cost-effective solution is difficult due to the incomplete knowledge on the mean and long-term crop plant response to climate manipulation.
Therefore, there is a need: for (i) specific background knowledge on the crop response to a given improvement in greenhouse design and climate control, and (ii) a methodology of optimisation that takes into account the response of the crop, the cost of the improved structure and climate control system, as well as some other parameters and criteria that are involved in the decision-making process.
The role of crop models and simulation tools is briefly discussed.
The second part of the paper deals with the present research trend in greenhouse technology, at the light of the publications on greenhouse environmental control during the late 90’. Some topics appear to merge, like ventilation, greenhouse transmission, and climate control.
Finally, the way the growers respond to technological improvements in their production system is discussed.
It is highly probable that the use of more performing greenhouses is of little value if not accompanied by a better education and training of growers.
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