AUSTRALIAN SALTBUSH. 



SOIL REQUIREMENTS. 



While the Australian saltbush has been noted as growing on prac- 

 tically all types of soil, it occurs in but few regions where the soil does 

 not contain a greater or less amount of alkali. Table II presents the 

 analysis of various soils in which it was found growing. It is to be 

 noted that the salt content ranges from nothing to 2.61 per cent of 

 the dry weight. This saltbush is quite tolerant of alkali, and will 

 thrive in soils that will grow but very few ordinary crops. 



DROUGHT RESISTANCE. 



The Australian saltbush is quite drought resistant, but apparently 

 not to the extent of some other species of Atriplex and many desert 

 plants. Table II gives the moisture content for the summer or 

 rainless season of various soils at San Diego, Calif., in which salt- 

 bushes were well established. The minimum moisture content was 

 1.51 per cent for the first 6 inches of soil and 1.75 per cent for the 

 first 12 inches. In soils with such low moisture content the plant 

 apparently can make no growth, but the fact that it exists under 

 such conditions and resumes growth when favorable conditions pre- 

 vail entitles it to be designated as drought resistant. 



Table II. — Sodium-chlorid content of the Australian saltbush and of the soil in California 

 in which it vjas found growing. 



[Analyses made by J. F. Breazeale; soil samples taken at San Diego, Calif., Aug. 23 and Sept. 4, 1918. ] 



Soil sample. 



No. 



Location. 



Weight (gramr). 



Initial. Dry 



Soil 

 mois- 

 ture 

 (per 

 cent). 



NaCl content 

 (per cent). 



Soil. 



Dry 



plant. 



90 feet from high tide 



120 feet from edge of salt flat 



Salt flat, at edge of seepage 



Edge of bay, moistened at high tide 



Mesa, near Sweetwater dam (first 6 inches of soil). 



Levee, 3 feet above water level 



Depression by levee, moist and alkaline: 



Topsoil 



Subsoil 



Salt flat, a 1 ittle above water level 



Dry soil, near Ramona 



Dry gravelly ridge, at Chula Vista: 



First foot 



Second foot 



Third foot (8 inches) 



Dry level spot not cultivated for 3 vears: 



Firstfoot ." 



Second foot 



Third foot 



Paso Robles 



265.0 



1.51 



.104 

 .035 

 .435 

 .710 

 .030 

 .047 



.110 

 .110 

 .610 

 .020 



7.01 

 8.17 

 8.17 



16.34 

 8.40 



13.05 



15.66 



23.20 

 4.64 



250.7 

 297.1 

 191.5 



250.6 

 312.3 

 356.8 



237.3 

 272.1 

 176.0 



239.5 

 293.0 

 330.0 



5.65 

 9.19 

 8.80 



4.63 



6.58 

 8.12 



In the extremely dry areas where the annual precipitation is low and 

 the surface soils usually dry, as in the Bakersfield and Mojave regions, 

 the Australian saltbush does not occur. However, in these regions 



