14 DRY-LAND OLIVE CULTURE IN NORTHERN AFRICA. 



form in size and shape. Nothing else is grown among them after 

 they begin to bear, and the cultivation is so clean that it is hard to 

 find a blade of grass in the well-cared- for orchards. 



This admirable culture is carried on without irrigation in a region 

 where the rainfall averages only 9.3 inches and sometimes falls as 

 low as 6 inches during several successive years. It is the most suc- 

 cessful example of dry farming applied to a tree crop of which 

 we have any knowledge. 



In order to understand the cultural methods practiced, it is neces- 

 sary first of all to know something of the physical conditions of the 

 Sfax region. 



GENERAL CHARACTERISTICS OF THE SFAX REGION. 



CLIMATE. 



Sfax, like most localities in northern Africa, has many of the 

 climatic peculiarities of the vast Sahara Desert, which practically 

 reaches the sea near the border of Tripoli, 110 miles southeast of 

 Sfax. For this reason the climate of the east coast of Tunis, even 

 as far north as the city of Tunis (fig. 1) is much more desert-like 

 than the coast of Algeria, which is separated from the Sahara by 

 two ranges of mountains. At Sfax the chief points in which the 

 climate approaches that of the desert are the small rainfall and the 

 long, hot summers. Yet it is not a typical desert climate, for the 

 neighborhood of the sea gives it a comparatively high relative 

 humidity and smaller daily and seasonal ranges of temperature 

 than those that characterize the Sahara itself. 



Table I shows the average monthly temperatures at Sfax : 



Table I. — Monthly and annual average mean, mean maximum, and mean mini- 

 mum temperatures at Sfax. in degrees Fahrenheit. 







Mean 



Mean 



Mdnth. 



Mean. 



of the ' 



of the 







maxima. 



minima. 





°F. 



°F. 



°F. 



January _._ _, _ 



61.8 



59.1 



43.3 



February _ _ _ _ _ .. _. __ . 



54.4 



61.8 



46.9 



March _ . . __ 



59.1 



67.2 



50.2 



April _ _ _ _ _ _ _ _ 



63.2 



72.1 



54.9 



May . _ __ 



68.8 

 72.8 



77.5 



60.5 



June ___^____ _ . _ 



80.9 



65.9 



July 



78.5 



87.8 



72.0 



August. _ _ _ ______ 



79.3 



88.1 



72.9 



September. _ ________ _ _ __ 



78.4 



86.6 



73.2 



October _ _ _ 



72.8 



79.4 



64.5 



November-. _ __ _ _ . _ __ _ 



61.8 



69.1 



53.7 



December.. ___ .__ 



54.0 



62.5 



45.8 





Annual mean.. _ .__ . __ _________ 



66.2 



74.3 



58.6 









a The monthly means for Sfax are based upon records covering a period that varies in 

 length for different months from eight to seventeen years, but they have been corrected so 

 as to agree with the sixteen-year means for each season (winter, spring, summer, and 

 autumn) given by G. Ginestous (Etude sur le Climat de la Tunisie, Bui. Dir. Agric. et Com. 

 Tunis, 1902 and 1903). The correction in most cases amounts to only about 1° F. and in 

 no case exceeds 3°. 



125 



