ARID AGElCULTUEE. 29 



not so poor in nitrogen as the laclv of humns 

 would indicate. But it is in looseness or floecula- 

 tion and mineral elements that our -western soils 

 excel. Of the salts of sodium and magnesium, 

 we have an ahundance and some to spare. ' Ex- 

 cessive accumulation of these salts through over 

 irrigation and lack of management causes the 

 waste spots of some f.o.rms where the land has 

 been taken with alkali. 



Of the more important minerals, as potash 

 and phosphoric acid, the most of oiir soils con- 

 tain 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 40,075 

 pounds of potash and 6,9Y0 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 poimds of 

 phosphoric acid per acre in the surface soil. This 

 shows over two and one-fourth times as much 

 potash and one and threei-fourth times as much 

 phosphoric acid in the arid soils which have been 

 studied. The manner in which these minerals 

 become available and are used by the growing 

 crops is another question. 



^„^„ This book is the first attemjjt to present to 



FABKiNCr A. the farmers of the West a handbook of agricul- 



NEW SCIEITCE 



ABID 



