GROWTH AND QUALITY OF TOMATO PLANTS GROWN IN SAND AND PERLITE BY THE USE OF GEOTHERMAL WATER

     Since 1980, many geothermal artesian wells were drilled for complementary irrigation of some oasis in arid zones of Tunisia, where date palm is the most dominant crop. This water had to be cooled before irrigation. Therefore, the idea was to use this water firstly for heating greenhouses and then for irrigation; this gives the opportunity to produce earlier vegetables during the cold period for export. However, geothermal water is saline with total dissolved solids ranged between 2 and 4 g/l and causes salt accumulation in the soil that in turn decreases crop yield considerably. To control soil salinity, a free-drainage soilless system based on local substrate (sand) can be adopted. In this work, we investigated growth and fruit yield of tomato plants grown in sand or in perlite. this system with another one using perlite substrate. Plant growth was faster in sand than in perlite. Marketable yield was not significantly influenced by the type of substrate. Fruit blossom-end rot occurred only in the last period of harvest (June) and its incidence was significantly higher in perlite.

Download Adobe Acrobat Reader (free software to read PDF files)