118 HATCH EXPERIMENT STATION. [Jan. 



It will be noticed that the no-nitrogen plots give only about 

 65 per cent, as much seed as the plots receiving nitrogen, and 

 about 73 per cent, as much straw. The nodules in which are 

 found the bacteria connected with the assimilation of atmos- 

 pheric nitrogen were very abundant upon the roots of the 

 plants upon all plots, as was determined by frequent exami- 

 nation. In spite of this fact, the supply of nitrogen at the 

 disposition of the plants on the no-nitrogen plots appears to 

 have been inadequate for even fairly vigorous growth. No 

 reason can be assigned, unless it be that the acid condition 

 of the soil prevented the normal action of the agencies con- 

 nected with the assimilation of atmospheric nitrogen. 



In conclusion, attention is called to the fact that nitrate 

 of soda must be regarded as one of the most desirable of the 

 materials that can be purchased as a source of nitrogen. The 

 cost of nitrogen in this form is lower than in most other 

 materials, and in this as well as in other experiments upon 

 our grounds it usually shows itself to be more effective than 

 any other nitrogen fertilizer. Its superiority to the other 

 materials used in this experiment is made more evident if in 

 place of comparing total jdelds we compare the increases in 

 yields produced by the several nitrogen fertilizers. On this 

 basis, including all crops raised to date, but tjaking into 

 account the seed only for this year, the different materials 

 rank as follows : — 



Belative Increases in Yields, Average for Fourteen Tears. 



Per Cent. 

 Nitrate of soda, ....... 100.00 



Barn^^ard manure, . . . . . . .77.80 



Dried ))lood, . . . . . . . . 65.10 



Sulfate of ammonia, . . . . . .63.60 



