REPORT OF THE SECRETARY. 63 



ability of the roots of plants from arid regions, as compared with 

 those from humid regions, to extract water from a nearly dry soiL 

 Economical use of the moisture available, as evidenced by the pro- 

 duction of a maximum crop with a minimum loss of water in trans- 

 piration, is believed to afford the best criterion of superior drought 

 resistance. An immediately applicable result of these physiological 

 investigations is the working out of a method for testing in the field 

 the comparative drought resistance of different species and varieties, 

 which it is believed can be successfully used, even in wet years, thus 

 greatly accelerating the progress of variety-testing and plant-breed- 

 ing work. 



As regards the indicator value of natural vegetation, the results 

 of preliminary studies in the Intermountain or Great Basin region 

 support the conclusion previously reached in the Great Plains area 

 that the native growth is the safest guide to follow in selecting new 

 land for agricultural purposes. Certain types of vegetation are 

 found to characterize land that is suitable for " drv farming." Other 

 types are a pretty certain indication that the water relations of the 

 soil are unfavorable or that there is a dangerous quantity of alkali 

 salts, even though the appearance of the surface soil ma}^ not indi- 

 cate the presence of alkali. 



Several bales of lint of the new Yuma variety of acclimatized 

 Egyptian cotton grown in Arizona in 1909 and 1910 were purchased 

 by one of the largest American firms which use this type of cotton 

 at a considerable premium above the price obtaining at Boston on 

 the date of sale for high-grade imported Egj'^ptian cotton. The 

 results obtained in spinning this cotton were highly satisfactory to 

 the purchaser. This additional assurance of the good quality of the 

 fiber, together with the satisfactory yields obtained at several dif- 

 ferent localities in the Southwest, justifies the conclusion that this 

 Yuma variety is well adapted to the commercial production of cotton 

 of the Egyptian type. 



DATE CTJLTURE. 



As the date trees of imported varieties now on trial gain in 

 maturity, their true characteristics and adaptation to particular con- 

 ditions become more apparent. The present year's results at Mecca 

 and Indio have brought into prominence a few varieties favorably 

 noticed for several years, but now definitely to be recommended for 

 trial on a commercial scale. 



With the fruiting of young trees grown from seed distributed to 

 department collaborators a number of new varieties of decided merit 

 are appearing, and certain imported sorts are showing an unusual 

 proportion of meritorious seedlings. We now have also for the first 

 time the opportunity of using pollen from male trees of known 



