42 DROUGHT RESISTANCE OF OLIVE IN SOUTHWESTERN STATES. 



The secret of this Hes in wide planting, not nioi-c than 11 trees to 

 the acre, and in clean cultivation, keeping the soil in a condition 

 to receive every drop of rainfall and to conserve it to the utmost, the 

 varieties used, chiefly Chemlali, being especially adapted to such 

 conditions and affording a high percentage of oil. 



The examples presented in this paper are those of the endurance 

 of extremes of drought and neglect by varieties of the olive com- 

 monly grown in the south of Europe under conditions of sufficient, 

 if not abundant, moisture. Their growth as trees in these arid 

 situations in Arizona and California, interesting and suggestive as 

 it is, would not warrant their maintenance as a commercial oil- 

 producing enterprise. But the Chemlali and other varieties of the 

 olive are profitably grown for oil production in the north of Africa 

 without irrigation, and under conditions of soil and climate fairly 

 comparable with those endured by the Arizona groves herein described. 

 Whether the Chemlali variety will make the profitable growth in 

 Arizona, California, and other sections of the Southwest that it has 

 in Tunis can only be determined by careful experimentation. 



The possibility that large areas of land within the proper tempera- 

 ture limits and having an ideal soil for the olive, yet without the 

 rainfall or irrigation water necessary for ordinary crops, may be 

 utilized for an olive-oil industry makes it worth while to institute 

 experiments of sufficient extent to thoroughly test the matter. Plant- 

 ings of more than an experimental character are not warranted by 

 the present extent of our information, and the production of pickling 

 olives is not contemplated. 



In each of the instances cited where olive trees have remained 

 alive and growing in spite of the failure of water it is necessary to 

 remember that the plantation was established under irrigation. 

 Likewise, in Tunis the truncheons by which the orchards are propa- 

 gated are carefully watered by a supply carried from wells until 

 sufficiently rooted to maintain themselves, three waterings usually 

 being sufficient during the first summer. In making selections of 

 tracts for olive culture over the drier areas indicated in Texas, 

 Arizona, and California it inust be a further condition, of success that 

 a small supply of water from some source can be assured to establish 

 the young trees, after which a local rainfall of 7 to 12 or 15 inches 

 annually may be expected to support the plantation and enable 

 it to produce fair yields of fruit — perhaps enough to render dry-land 

 olive culture profitable on a commercial scale. 



SUMMARY. 



In several localities in southern California and Arizona olive groves 

 have been planted along with apricots, figs, grapes, and some other 

 fruits. The irrigation projects under which these plantings were 



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