Performance evaluation in olive trees irrigated by treated wastewater

Nineteen olive tree varieties were placed in the region of Tataouine (Tunisia) irrigated by wastewaters and studied intensively. The agronomic follow-up of two years dealt with the production by tree and vegetative growth. The study revealed a significant variability between the varieties, at the level of the parameters measured. For production, good performances were exhibited by Chemlali Ontha and Koroneiki in 2005 and by Chetoui and Koroneiki in 2006. In the two years of this study, we noticed that the table and oil-table varieties, with the exception of Picholine, were weakly productive and Meski was even non productive. Six oil varieties have the highest averages of production with a maximum for Koroneiki. The absolute average production gap by tree between the years was variable for these varieties and minimal for Chemlali Sfax, Chemlali Ontha and Koroneiki. Koroneiki holds both — a weak gap and the highest average production. For the vegetative growth, a big similarity was observed in the varietal response between the increase of the canopy volume and area; and the trunk cross section. Thus the best performances were shown by Chemlali Tataouine in 2005 and Dhokkar in 2006 and the lowest ones by Touffehi in 2005 and Chemlali Sfax in 2006. For the shoot of a year, the lengthening was always maximum for Marsaline and minimal for Neb Jmel but with a variable response between the years according to the varieties.