1912.] PUBLIC DOCUMENT — No. 31. 27 



cial, but in this case, also, an increase above the rate of 46G 

 pounds per acre of nitrate is not followed by a further increase 

 in the crop. 



li. Xitratc of soda has been applied according to three dis- 

 tinct plans: — 



(a) All applied in early spring. 



(h) One-half applied in early spring and the balance at the 

 close of the cutting season, 



(c) All at the close of the cutting season. 



These variations in method of applying have been tried with 

 nitrate of soda in diifering amounts and in varying combina- 

 tions. 



The variation in season of application is not followed by any 

 well-defined diiference in yield, but the amount of rust has ap- 

 peared to be less with the larger applications applied at least in 

 part after the cutting season. In other words, nitrate of soda so 

 applied and in such liberal quantities as to promote a contin- 

 uous vigorous growth of the ])lant after the close of the cutting 

 season seems to increase the capacity of the plants to resist rust. 



4. Among the different materials used as the source of potash, 

 viz., muriate, high grade sulfate, low grade sulfate, wood ashes, 

 and kainit, the plot receiving the latter showed the least rust. 

 It is important, however, to point out that this may have been 

 in part a consequence of the fact that the plot was located on 

 the side of the field lying at the greatest distance from the fields 

 which are believed to have been the chief sources of rust infec- 

 tion. The comparative freedom from rust of the plants on the 

 kainit plot, therefore, may have been due in large measure to 

 location. The decided difference, however, in the amount of 

 rust on this plot and on the one immediately adjoining it, the 

 location of which with reference to rust infection is not very 

 different, lends probability, at least, to the conclusion that the 

 kainit exercised a favorable influence in preventing rust. 



5. Acid phosphate used in connection with nitrate of soda 

 and muriate of potash has given a considerable increase in crop. 

 This increase is greatest where the acid phosphate is used at the 

 maximum rate of 188.7 pounds p(;r acre. 



G. Muriate of potash used in connection with nitrate of soda 



