A NEW SYSTEM OF TOMATO GREENHOUSE CULTIVATION: HIGH DENSITY AEROPONIC SYSTEM (HDAS)

The study is aimed at testing whether it is possible to grow greenhouse tomatoes at high density with the aeroponic system. The experiments were carried out in 1991 and 1992 at the CRAS experimental farm in the south of Sardinia. A system for aeroponic culture was prepared using low cost materials and following the "inclined panel" scheme.

In 1991 a preliminary experiment was conducted using Cherry type tomato hybrids. In 1992 two cultivation cycles were carried out using hybrids of normal sized fruit. The planting density was of 20 plants per square metre of plot in the first two cycles of cultivation, and 35 plants per square metre of plot in the third. About 30 days after transplantation, the tops of the plants were trimmed one leaf above the first cluster and left to grow without any support.

The results obtained were interesting for the quality and quantity of the yields. Among the Cherry types, the Cherry Wonder hybrid yielded 5.0 kg product per square metre. With the same plant density (20 plants per square metre) the hybrids Max. Vivia and OR 1750 yielded over 6.0 kg per square metre, and Camone over 5.8. In the third cycle with a density of 35 plants per square metre, the hybrids Timpa. Concorde, Fontana and Amfora yielded between 7.5 and 8.0 kg per square metre of fruit of excellent commercial quality in only two harvests.

The results show that the system can have a remarkable applicative value. In very short times in fact (about 3 months after transplantation), economically interesting yields can be obtained. Moreover, this system allows at least four cultivation cycles in 12 months.

The only limitation at present is the high cost of the hybrids used. Our future research is aimed at finding cheaper varieties with characteristics suitable to this type of utilization.