I. Slomnicki, I. Rylski
Thermophyllic vegetables such as tomatoes, sweet pepper and eggplants are cultivated in Israel under plastic tunnels without additional heating. Under these conditions the night temperatures are rather low and every degree centigrade is of importance. The night temperature inside the tunnels depends on the amount of heat emitted by the soil and this in turn depends on the amount of energy absorbed by day. The black color of asphalt coating causes a rise of soil temperature (Takatori et al.) by day and by night. Experiments of Thomas (1961) and Takatori et al. (1963) showed that rise of temperatures may hasten emergence of seeds.

The advantages of earlier emergence of seeds in spring can be multiplied if care is taken to protect the young plants against possible adverse climatic conditions. Plastic tunnels provide a good shelter for young plants which were sown or planted and allow the black mulch to perform at his best.

Most experiments are concentrated on the use of quite narrow pands of asphalt mulch in the open, in order to save soil moisture (Lippert et al., 1964) and hasten seed emergence by soil temperature rise. (Takatori F.H. et al., 1964, Hillel, D. 1965). In our experiment we tried to cover the entire base of the plastic tunnels in order to have the soil absorb as much additional solar energy as possible, and to protect the plants by the plastic tunnels.

Slomnicki, I. and Rylski, I. (1968). VEGETABLE FORCING UNDER POLYETHYLENE TUNNELS WITH BITUMEN MULCH. Acta Hortic. 9, 181-184
DOI: 10.17660/ActaHortic.1968.9.30

Acta Horticulturae