330 NATURE AND PROPERTIES OF SOILS 



Table LXXV 



comparison of alkali expressed in percentage op the dif- 

 ferent salts present. 





1H 



a M 

 OH 



ftS s &^ 



3 p d^ 



Yakima/ 

 Wash. 

 12-24 

 Inches 



^ILLINGS, Mont." 



Yuma, Aeiz.^ 



Salt 



Ckust 



SUKFACE 

 10 



Inches 



21.4 



35.1 



7.3 



4.0 



22.0 

 10.0 



Ceost 

 4.0 



81.1 



7.7 

 .2 

 .3 



6.6 



0-72 

 Inches 



KCl 



K2SO4 



K2CO3 



Na^SO,. . . . 



NaNOa 



Na^COa.... 



NaCl 



Na,HPO^ . . . 



MgSO, 



MgCl, 



OaCl^ 



NaHCOj... 

 OaSO^ 



CaCHCOJa 

 MgCHCOJ. 



(NHJ,C03 



1.6 



33.1 

 6.6 



12.7 

 17.3 



21.5 



3.9 



25.3 



19.8 



32.6 



14.7 



2.2 



1.4 



5.6 

 9.7 



13.8 



36.7 



1.9 



16.5 



15.7 



1.6 



85.6 



.5 

 8.9 



.6 



2.7 



22.0 



13.7 



6.9 

 4.0 



21.0 

 32.2 



Carbonates of tlie alkalies, particularly sodium carbonate, 

 dissolve organic matter from the soil, thus giving a dark color 

 to the solution and to the incrustation. For this reason, alkali 

 containing large quantities of these salts is called Hack alkali 

 Black or brown alkali may also be produced by calcium chlo- 

 ride or by an excess of sodium nitrate. 



Black alkali is much more destructive to vegetation than is 

 the white. A quantity of the latter which would not seriously 



^Headden, W. P., The Fixation of Niirogen; Colo* Agr. Exp. Sta., 

 Bill 155, p. 10, 1910. 



"Hilgard, E. W., SoilSy p, 442, New York, 1906. 



^Borsey, 0. W., Alhah Soils of the Umted States; U. S. Bept. Agr,, 

 Bur. Soils, Bui. 35, 1906. 



