EFFECT OF DIFFERENT GREENHOUSE COVERING MATERIALS ON INSIDE CLIMATE AND ON THE DEVELOPMENT OF TOMATO PLANTS

Greenhouse cultivation is being rapidly developed in the coastal areas of the Mediterranean Region of Turkey. Among the problems confronted in plastic houses is the selection of greenhouse covering materials which are normal PE, or PE containing UV and IR resistant additives. In recent years, the antifog PE which is widely used abroad has also been manufactured locally.

The reported work was conducted in three different greenhouses which all have the same constructional features, but which used different covering materials, containing UV, UV+IR and UV+IR+antifog constituents. Their effect on greenhouse climate, biological and agronomic characteristics of a tomato crop were studied. Among the climatological factor, inside and outside greenhouse temperature, humidity and solar radiation were observed. Light and radiation transfer in different greenhouse covering materials were changed from 75 to 80 %. Inside temperature of greenhouses covered with UV+IR containing materials was 0.5°C higher compared with other greenhouses. The difference increased to 1.5 °C when compared with plastic coverings containing no other constituents. Humidity was somewhat higher under plastic cover, containing antifog agent.

Different plastic covers had no effect on plant height, stem diameter, leaf area and plant dry matter. Fruit setting was somewhat lower (% 71.7) under the plastic, containing UV+IR+antifog constituents than other type covers (% 77.3). The yields under UV, UV+IR and UV+IR+antifog constituents were 5997, 6359 and 6390 g/plant, respectively.