WATER-USE AND YIELD OF GREENHOUSE-GROWN EGGPLANT UNDER DRIP IRRIGATION

The water consumptive use of eggplant, hyb. Delica, grown in unheated greenhouse was determined using tensiometers. The maximum evapotranspi ration (ET(m)), when soil water potential was maintained at values hig her than -20 KPa, ranged from 0.5 to 4.5 mm day(-1), with a whole seas on irrigation requirement corresponding to 380 mm. Water amount equal to 0.85 X ET(m) had no effect on fruit yield, which was 6.5 kg per pla nt; water application of 0.65 X ET(m) and 0.40 X ET(m) reduced total y ield by 35% and 46%, respectively. Fruit number per plant was signific antly reduced at 0.65 X ET(m) and 0.40 X ET(m), while fruit size was n ot affected by the amount of water applied. The crop ET(m) in October (at planting) was 0.2 of A pan evaporation (E(pan)) located outside th e greenhouse. This value remained constant until February and then inc reased gradually to 0.8 X E(pan) at the end of the experiment, in May. Salt content was higher at the surface 10 cm soil layer with all amou nts of water applied. With 1.00 X ET(m) and 0.85 X ET(m) salts were le ached out of root zone, while an additional amount of water was requir ed at 0.65 and 0.40 X ET(m) for salt leaching.