ISHS Acta Horticulturae 614: VI International Symposium on Protected Cultivation in Mild Winter Climate: Product and Process Innovation
INNOVATIVE TRENDS IN SHELTER CHARACTERISTICS FOR PROTECTED HORTICULTURE IN SICILY |
| Authors: | G. La Malfa, A. Cicala, S. La Malfa, S. Pulvirenti |
| Keywords: | protected cultivation, history, shelter typologies, present trends |
| Abstract:
The protected cultivation of horticultural crops based mainly on the use of plastic as material for covering the structures, is progressively going through an evolutionary process that also concerns the shelter typologies. The process in Sicily, as well as in other Italian regions, is in response to the needs of: a) adapting shelters to plant shape and size and to canopy volumes; b) mitigating stressing climatic conditions occurring in unheated plastic greenhouses; c) promoting the setting up and the spreading of more sustainable cultivation protocols. Concerning the first requirement, more and more new shelters have appeared. The most significant - apart from mini tunnels and direct covers – are walk-in medium-sized tunnels, still home-made but now set up with metal structures, to protect melons, strawberries and other shallow vegetable crops. They are now very common along the eastern Mediterranean coast of Sicily especially for melon production. The present diversification of shelters used to protect table grapes in order to have an earlier or later production can also be referred to the same requirement. A particular shelter typology (tendone) is widely diffused with the covering material applied either on a whole plant line or for each single plant (fazzoletto); tunnels, saddle roof and multi-span greenhouses (capanna and capannina) are also used for earlier production. In order to control the stressing conditions, we should underline the progressive substitution of traditional wooden greenhouses for growing vegetables and flowers with the new typologies that are being built, more and more, with new materials and criteria. Greenhouses with bent and wooden roofs, double covered to reduce heat losses during the night are now used; other changes concern roof shape rounding in order to make positioning the plastic film on the structure easier and cheaper. Concerning the materials we also report the use of galvanised pipes, mainly for building tunnels or multi-tunnels. Wooden greenhouses are disappearing more and more, while wooden components are still being used together with concrete piles. A common innovation for new greenhouses is the raising of their height thus achieving more unitary volumes; roof openings are also used but they have consequences on the criteria for double covering application. With the aim of improving ventilation, the adoption of roof windows or other similar devices is now considered for table grape shelters too, especially large multi tunnels or multi-span structures. In relation to the aim of setting up new cultivation methods, or improving the previous ones, we must stress the use of higher greenhouses and/or arranged so as to make it easier for them to be covered with shading nets. This allows a reduction of seasonal as well as daily thermal excursions and consequently a more prolonged utilisation of the greenhouses all year long. Within the framework of new cultivation protocols we would like to point out the wide use of plastic nets applied on shelter windows so to avoid the entrance of dangerous insects as well as keeping the pronubes, released to promote the fruit setting, inside the greenhouse. Increasing attention is finally being paid to the shape and the slope of greenhouse roofs, in order to collect rain water, as well as to the devices for soilless culture. New shelter typologies will surely go on being created as the need for further improvement in productive processes for yield, quality and sustainability becomes more and more pressing. | |
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