13 



The alkali map accompanying this report (p. 1.1) outlines five grades 

 of .soil as to alkali content: 



These grades represent the average for the surface 6 feet, tests 

 having been made for each foot in depth and the arithmetical mean 

 taken. At the end of this report a table is given showing the per 

 cent of alkali in each foot of depth for all the borings. 



The to 0.2 per cent grade is soil that is practically free from alkali. 

 No crops but the most sensitive would be injured by this percentage. 

 Almost all common crops will withstand from 0.2 per cent to O.-i per 

 cent. Barley, corn, alfalfa, watermelons, cantaloupes, and most of the 

 berries, grapes, figs, apricots, and peaches will do almost as well in this 

 grade of soil as in lands that contain much less, the chief danger in 

 growing fruits being the fact that their roots are liable to go deep into 

 the subsoil and thus reach the alkali accumulated there. Alfalfa will 

 barely grow in the OA to 0.6 per cent soil, even when well matured. If 

 once a stand is secured it will struggle along, unless there be a concen- 

 tration caused by the irrigation. Barle} 7 will produce a crop, though 

 not first class. Pear trees will grow for a time at least, and if the sub- 

 soil be no worse than the surface and no concentration near the surface 

 takes place they would thrive indefinitely. 



All land that contains more that 0.6 per cent of alkali must be han- 

 dled very carefully to produce any kind of crops except the most 

 alkali resistant. Careful and proper methods of cultivation may result 

 in washing enough of the alkali of the surface 2 or 3 feet into the sub- 

 soil so that shallow-rooted crops, such as annuals, can be grown. But 

 until this surface reclamation takes place only such crops as sorghum, 

 date palms, and sugar beets can be grown. On all the soils that con- 

 tain more than 1 per cent of alkali date palms and saltbushes are the 

 only crops that will thrive. In the Sahara date palms will grow on 

 lands containing as much as 3 per cent of alkali. 



The alkali map shows the conditions to a depth of 6 feet onh', but 

 as alkali salts have been known to rise to the surface from much 

 greater depths, it is important to know the amount of alkali in the 



