% ARID AGRICULTURE. 29 



not so poor in nitrogen as the lack of humus 

 would indicate. But it is in looseness or floccula- 

 tion and mineral elements that our western soils 

 excel. Of the salts of sodium and magnesium, 

 we have an abundance and some to spare. Ex- 

 cessive accumulation of these salts through over 

 irrigation and lack of management causes the 

 waste spots of some farms whore the land lias 

 been taken with alkali. 



Of the more important minerals, as potash 

 and phosphoric acid, the most of our soils con- 

 rain enough for a long series of years of crop- 

 ping. An average of thirty-four analyses of 

 soils from Colorado, Wyoming and California, 

 taken consecutively, though somewhat at random 

 from the reports, gives approximately 40.07.") 

 pounds of potash and 6,970 pounds of 

 phosphoric acid per acre in the surface 

 soils, given in Roberts' "Fertility of the Land." 

 all but one of which are from -the East and South, 

 gives 17,599 pounds potash and 3,936 pounds of 

 phosphoric acid per acre in the surface soil. This 

 shows over two and one-fourth times as much 

 potash and one and three-fourth times as much 

 phosphoric acid in the arid soils which have been 

 studied. The manner in which the^e minerals 

 become available and are used by the growing 

 crops is another question. 



ABID This book is the first attempt to present to 



FARMING A the farmers of the West a handbook of aaricnl- 



NEW SCIENCE 



