WATER BALANCE IN GREENHOUSES UNDER POLIETHYLENE COVER: FIRST RESULTS FOR GALICIA (NW SPAIN).

Despite the importance recently gained by greenhouse cultivation under plastic cover in NW Spain, few works are dedicated to study the different production components. Practices and techniques employ correspond to those of the spanish mediterranean areas, without any adaptation to the atlantic conditions of Galicia.

This paper presents a first analysis of inputs and ouputs water relationships for greenhouses dedicated to cut-flower production, for a four year period (1988–1991). Results indicate that common irrigation doses does not attain the potential needs of plants. Deficit was observed in winter-spring, spring and/or spring-summer seasons, with different intensities, though it can be considered as high (> 100 mm per year in most cases). While water surplus seems not to be an important limitation for flower production.