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DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



less inevitable from the nature of the ground; but there seems to be 

 no good excuse for the small attention that is paid at Susa to prun- 

 ing, as compared with the thoroughly scientific way in which this 

 operation is performed in the Sfax orchards. 



Many of the trees have several trunks, which is explained by the 

 natives as having been due to a violent storm, which a century ago 

 laid low most of the olive trees around Susa, after which event 

 several shoots at the base of each tree were allowed to spring up. a 

 The greater part of the olive trees around Susa are of great age, 

 often 100 or 150 years old, it is said. But when well cared for with 

 respect to cultivation of the soil, pruning, and manuring, even these 

 old trees are reported to give good returns, netting the owners in 

 some years as much as 95 cents to the tree, or $38 per acre. & 



SUMMARY. 



(1) Arboriculture is an important phase of dry-land agriculture 

 and one that has as yet received little attention in the United States. 



(2) The olive, owing to its peculiar leaf structure and to the char- 

 acter of its root system, is especially fitted for growing in regions 

 where the rainfall is slight and irrigation is impossible. 



(3) Fifteen hundred years ago the olive was grown without irriga- 

 tion under a rainfall of from 8 to 14 inches over an extensive region 

 in northern Africa, the prosperity of which in Roman times depended 

 chiefly upon its production of olive oil. A vast region that is now 

 practically an uninhabited desert was then covered with olive orchards 

 and with flourishing cities and towns. 



(4) During the last hundred years much progress has been made 

 in reestablishing dry-land olive culture in southern Tunis. There 

 are now nearly 500,000 acres of unirrigated olive orchards in the 

 neighborhood of Sfax. 



(5) As would be expected from its nearness to the Sahara, the cli- 

 mate of Sfax is almost desert-like. The summers are very hot and 

 the average annual rainfall is only 9.3 inches, sometimes falling below 

 an average of 6 inches for seven consecutive years. As in California, 

 the summer is the dry season and the winter the wet season. 



(6) The ground water lies too deep to be reached by the roots of 

 the trees. No water is available for irrigation. 



(7) The soil of the Sfax region that is considered best adapted to 

 olive culture is a red loam or fine sandy loam that is fairly uniform 

 in texture to an average depth of seven feet. It is very retentive of 

 moisture, rich in lime and potash, but apparently deficient in nitro- 

 gen and phosphoric acid. 



a Minangoin, X. L'Olivier en Tnnisie, Tunis, 1901, p. 32. 

 & Minangoin, N., 1. c, p. 54. 



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