B. P. I. — 337. 



DRY-LAND OLIVE CULTURE IN NORTHERN 



AFRICA. 



INTRODUCTION. 



A great awakening to the possibilities of clry-land agriculture has 

 recently taken place in the western United States. Land is being rap- 

 idly taken up and brought under the plow, largely by eastern farmers, 

 in regions where the average yearly rainfall does not exceed 18 inches 

 and where water is not available for irrigation. The unusually 

 heavy rainfall of the past few seasons has alloAved many of the new- 

 comers to obtain good crops of small grain and forage under these 

 conditions ; but the recent recruit to " dry farming " must not lose 

 sight of the fact that such periods of unusually heavy rainfall are 

 sure to be followed sooner or later by periods of drought, when the 

 plants ordinarily grown in humid regions will give him but uncer- 

 tain results. To insure against disaster he should be on the lookout 

 for drought-resisting varieties of the crop plants he is familiar with 

 or else for new crop plants adapted to arid conditions. 



No class of plants is more resistant to drought than certain trees 

 and shrubs, some of which are extremely useful in countries having 

 a climate similar to that of the Great Plains and Great Basin regions 

 of the United States. Arboriculture (tree culture) is one of the 

 safest and most promising lines along which dry-land agriculture 

 can develop. Experience in various parts of the Old World has 

 shown that drought-resisting trees will live and will often produce 

 a crop in years when no shallow-rooted annual crop will return the 

 seed sown. 



The most highly developed and successful example of dry-land 

 arboriculture known to the writer is based on the olive, a tree that 

 is peculiarly well fitted for growing under arid conditions. Its 

 leaves are protected against excessive loss of water by the thick skin 

 or cuticle of the upper surface and by the scurf of scale-like hairs 

 with which the under side is covered. Its root system is of such a 

 nature as to permit it to grow without irrigation in regions where 

 the rainfall is scanty and the ground water is practically out of 



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