This study was conducted during two successive late summer seasons of 2015and 2016 at a private farm on Cairo-Alex Desert Road-Km73 (Agricultural Almostakbal Association), Giza Governorate. In this study the effects of three plant densities i.e., 14000, 12000 and 10500 plants per fedden along with three levels of aluminum silicate (kaolin), i.e., 1, 2 and 3% added as foliar spray beside the control (tap water) were studied. Data collected wereon vegetative growth, flowering characteristics, fruit yield and its quality of processing tomato, hybrid Alissa F1. Kaolin application started fifteen days after transplanting and repeated at every 8 to 10 days until the beginning of fruits coloring stage. The field soil was sandy in texture and drip irrigation system was used.
The obtained results showed that using the highest plant density of processing tomato, i.e 14000 plant (30cm spacing between the seedlings) produced the taller plants, high weight of fresh and dry leaves, the highest fruit setting% with high early, total and marketable yield as well as low percentage from sunscald affected fruits. However, such treatment (highest plant density) produced the lowest fruit weight, firmness and fruit contents from vitamin C ,T.S.S as well as pH of juice. The lowest plant density produced low fruit yield with high percentage of unmarketable fruit, but the fruits were bigger, had highest weight, were firmner, and had high concentration from vitamin C, T.S.S and pH of juice, than those harvested from plants grown in higher densities.
Concerning the effect of foliar spray with aluminum silicate kaolin, it is obvious from the results, that the level of 2% significantly increased all traits of vegetative growth, enhanced earliness of flowering and increased fruit setting, total and marketable yield with superior characteristics, i.e, fruit weight, less infection with sunscald fruits, high firmness, high vitamin C, T.S.S as well as pH of juice contents.
For that, it can recommend under the condition of planting the processing tomato in the late summer seasons under sandy soil under drip irrigation system with high density plant per fedden(14000 plant), i.e., 30 cm spacing between plants and foliar spraywith 2% aluminum silicate to obtain highest marketable fruit yield and reach to highest productivity.