THE EFFECT OF FLAT PLASTIC-FILM COVERING ON THE DEVELOPMENT OF LETTUCE
It has been possible to determine with greater precision the relationship between meteorological or microclimatic conditions and the behaviour of specific plants in two ecologically different places.
The trials concerned lettuce which, after being planted out, was given a direct cover of polythene film of 8,15,21 or 23 days. In the more continental climate of Geisenheim, there was more sunshine, and the weather was drier than at St.Katelijne-Waver.
These different climates account for the fact that the averages both of fresh and dry weight was lower at Geisenheim than at St.Katelijne-Waver. The size of leaves was also smaller at Geisenheim whereas the number of leaves was larger there than at St.Katelijne-Waver.