SHELTERS FOR CULTURES IN THE MEDITERRANEAN COUNTRIES

A. Nisen
The shelter, which modifies the "natural" climate through its own characteristics and the properties of its cover, creates a new climate, known as "derived" climate. This deserves an accurate definition. On the other hand, the shelter must suit the climate under which it has been built. Thus, we cannot speak of a "unique" shelter but of a"manifold" one, designed to meet the conditions and the periods of use it has been created for.

In the first chapter the"Mediterranean climate" is briefly characterized : average monthly temperatures always over 5° C, rainfall limited to only one humid period which coincides with winter, insolation always superior to that in other European countries, dry and often cold winds with predominant orientation on the major part of the countries of the Mediterranean Basin. However, the variability of the weather increase with distance from the sea winds are of relatively great importance. A quick survey of the covering materials and of the main types of shelters appears in chapter 2. The Mediterranean Basin is an appropriate place for "plastic" shelters whose temporary cover is a film of polyethylene or of polyvynil chloride of short duration.

Chapter 3 studies the change in climate caused by shelters. Indeed, it would be wrong to believe that the mere presence of a shelter creates by itself "derived" climate and "plant requirements", and suppresses any further human work. Both the actual fact (natural climate) and the final target (requirements of the plants grown) are of obvious importance in the choice of the cover and thereby of the shelter. Such considerations appear unfortunately insufficient to bring a solution to all the problems owing to their complexity and to the variability in space and time of the weather.

Finally, in the fourth chapter, entitled "The Use of Shelters in Mediterranean Areas", the author tries to connect human problems and weather conditions and gives a general survey of the present situation in the various countries of the Mediterranean Basin.

If the countries in the North-West and North of the Mediterranean Basin have already gained a thorough knowledge of the problem - it has taken them between 5 and 12 years - others, with their more peculiar climate and where the need for a sheltered culture has not been felt so acutely so far,

Nisen, A. (1974). SHELTERS FOR CULTURES IN THE MEDITERRANEAN COUNTRIES. Acta Hortic. 43, 13-42
DOI: 10.17660/ActaHortic.1974.43.1
https://doi.org/10.17660/ActaHortic.1974.43.1
French

Acta Horticulturae