36 EXPEULMENT STATION. [Jan. 



Per Cent. 



Nil rale of soda, 100.00 



Barnyard manure, 94.07 



Dried blood, 92.38 



Sulfate of ammonia, 86.87 



No nitrogen, 71.96 



On the basis of increase in crop as compared with the no- 

 nitrogen plots^ the average of the twenty-one years shows the 

 following relative standing: — 



Per Cent. 



Nitrate of soda, 100.00 



Barnyard manure, . . . . . . , . .78.85 



Dried blood, 72.82 



Sulfate of ammonlM, ......... 53.17 



Xitrate of soda has given a much larger increase in crop 

 than any of the other materials, and since the pound cost of 

 the nitrogen of nitrate of soda is usually less than the pound 

 cost in any other chemical fertilizer, the superior economy of 

 its use is apparent. 



II. ]\Iui;iATE COiSIPAKED WITH SuLFATE OF PoTASII. 



Our long-continued experiments comparing muriate with 

 high-grade sulfate as a source of potash have continued on Field 

 B. It will be remembered that the two potash salts are used in 

 such quantities as to furnish equal actual potash per acre. 

 These experiments were begnn in 1892. Five pairs of plots are 

 under comparison. From 1892 to 1899 the potash salts were 

 used in quantities (varying in different years, but always in 

 equal amounts on the two members of pairs of i)lots) ranging 

 from 350 to 400 pounds per acre. Since 1900 the quantity used 

 has been uniform on all plots, and at the rate of 250 pounds per 

 acre annually. Fine ground bone has been annually applied 

 to each plot throughout the entire period of the ex])eriment, 

 and the rate of application is GOO jiounds per acre. The season 

 of 1910 is the nineteenth year of these experiments. The crops 

 during that year were potatoes on one ]y,\n- of plots, oats on one 

 piiir. and asparagus, rhubarb and blackberries. The rates of 

 yield ])er acre on the differcMit ])otash salts are shown in the 

 following tables: — 



