干旱区生态环境知识资源中心

In Tunisia, olive tree is often cultivated on a dry farming system with a large layout (24 x 24 m in arid zones). It develops an important vigor with a compact crown. The fruit setting and the olive production vary considerably according to the rainfall and depending on the soil type, the anterior productions and the tree age. Experimental observations were carried out between 1984 and 1999 on orchards planted before 1912 and located at Safsafa farm (Chaal, Sfax). Results show that the olive production (between 1939/40 and 1999/2000) is subject to a wide variation due to the tree age evolution. Olive yield averages pass yearly from 25 kg when tree is young to 95 kg /tree /year between 30 and 65 years old. When the orchard age exceeds 65 years, harvest decreases gradually to 30 kg per year. A hard pruning (consisting of cutting the big woody branches or shortening the large distance separating the central axis and the fruiting branches) was done in 1986 and insures an increase of 45% olives production averages. It permits to increase vigor and yields, which reach 55 kg per tree and per year.