1910.] rUBLIC DOCUMENT — No. 31. 39 



Pounds. 



Muriate of potasli : — 



Hard heads, 17,406 



Soft heads, 6,878 



High-grade sulfate of potash: — 



^ Hard heads, 21,960 



Soft heads, 2,434 



III. In Fiekl C wc liave under comparison for use in 

 connection with manure three different materials used as a 

 source of nitrogen, ^ — sulfate of ammonia, nitrate of soda and 

 dried blood, — and the two potash salts, muriate and high- 

 grade sulfate, each salt being used Avith each of the three 

 nitrogen fertilizers and in connection with a liberal applica- 

 tion of dissolved bone black, the same on all plots. The com- 

 parison of these different fertilizers in this field was begun 

 in 1891, but up to the year 1898' they were used without 

 manure. Since that time all plots receive annually a dressing 

 of stable manure, at the rate of 30 tons per acre. A large 

 variety of crops has been grown in this field. The crops the 

 past year were asparagus, rhubarb, cauliflower and onions. 

 Rhubarb and cauliflowers have given the heavier yields on 

 sulfate of ammonia as a source of nitrogen ; but both asparagus 

 and onions have given smaller yields on this material than 

 on either of the other nitrogen fertilizers. Nitrate of soda gave 

 a yield of asparagus about 25 per cent, greater than sul- 

 fate of ammonia, while for onions the diflerence in favor of 

 the nitrate of soda was in much greater proportion. With 

 muriate as the source of potash, the yield of No. 1 onions on 

 the different nitrogen fertilizers was at the following rates per 

 acre : — 



Bushels. 



Sulfate of ammonia, 359.2 



Nitrate of soda, 565.1 



Dried blood, 515.9 



With sulfate of potash as the source of potash the rate of 

 yield of No. 1 onions per acre for the different nitrogen fer- 

 tilizers was as follows : — 



Bushels. 



Sulfate of ammonia, 412.0 



Nitrate of soda 703.6 



Dried blood, 557.5 



