Although the results are merely indicative ,they emphasise that season-al evapotranspiration depends on the length of the cropping season as well as on growing period during the year. More general and useful indications for practical use are drawn from ETm/Epan ratios during the cropping cycle of each species under consideration.
The crop ETm in October for tomatoes was 0.3 of class A pan, located outside the greenhouse, reaching a maximum of 0.45 during November, then declined until February, and then started to increase again (Figure 3). The increase in ETm/Epan noticed at the initial stages of growth of tomato has been also reported by Graaf and Ende (1981). For cucumber the ETm/Epan ratio increased from 0.2 at planting to 1.1 at the end of cropping season in November.
For eggplant and pepper the crop ETm in October (at planting) was 0.2 of class \pan evaporation (Epan). This value remained constant until February and then increased gradually X Epan for pepper and to 0.8 X Epan for eggplant at the end of the experiment, in May (Figure 3). The same course followed the ratio between ETm to potential evaporanspiration rates calculated by radiation method