THE INFLUENCE OF ENVIRONMENTAL CONDITIONS OF MILD WINTER CLIMATE ON THE PHYSIOLOGICAL BEHAVIOUR OF PROTECTED CROPS

Simple greenhouse structures, and poor equipment for climate control which are used in mild winter regions, together with the influence of the natural climate, are the causal agents of the greenhouse microclimate, which is advantageous, on the one hand, because it makes intensive out-of-season cropping possible for a wide range of vegetables and ornamentals.
But, on the other hand, it is limiting for the crop potential productivity, owing to a number of conditions difficult to deal with.
It is common to reach extreme values for some of the factors in only a few hours’ time.
This is frequent with maximum and minimum temperatures and humidities.
Irradiance is generally high, but it is quite often modified due to growing practices as double covering or the use of shading materials, which produce losses of light that can affect growth.
The poor ventilation closes the indoor atmosphere, which gradually changes its composition.
The effects of these factors on some important physiological parameters, as well as the consequences on the growing techniques, are discussed in this paper.

III International Symposium on Protected Cultivation in Mild Winter Climates

P.F. Martínez

https://doi.org/10.17660/ActaHortic.1994.357.3