2l6 



MOVEMENTS OF SALTS IN THE SOIL 



California and Montana. Nitrates are more abundant in 

 white alkali soils than in soils containing black alkali. The 

 quantity is sometimes very large. In one of the alkali soils 

 at the Tulare Experiment Station, Hilgard found 4,300 Ib. 

 of sodium nitrate per acre in the surface foot of soil. Sodium 

 phosphate is chiefly found in soils containing black alkali. 

 Sulphate of magnesium is a common constituent of the salts 

 of the Yellowstone Valley. Analyses of some typical alkali 

 salts will be found in Table XXXVI. 



TABLE XXXVI 



PERCENTAGE COMPOSITION OF SOME TYPICAL ALKALI SALTS 



(HILGARD) 



The analysis in the left-hand column shows a salt consisting 

 almost wholly of sulphate of sodium, with some sulphate of 

 potassium. The next analysis exhibits the presence of 

 sodium chloride, with sodium nitrate. Following this we 



