156 STORRS AGRICULTURAL EXPERIMENT STATION. 
tenth to one-twentieth acre each, to which were applied the 
various fertilizer ingredients (nitrogen, phosphoric acid, and 
potash) singly, two by two, and all three together. . 
Results. — The experiments in which dried blood was used 
as a source of nitrogen were so few that no deductions from 
the yield of the crop can be made concerning the economy in 
using this material for fertilizer. From the experiments with 
the other materials supplying nitrogen it would appear that 
there was more advantage in the use of nitrate of soda than in 
the use of sulphate of ammonia. This was due rather to the 
higher cost of the sulphate of ammonia than to its lower effi- 
ciency as a fertilizer, although slightly larger yields were 
usually obtained on the plots where nitrate of soda was used. 
In the experiments with mixed grasses it was found that 
nitrogen in the fertilizer increased very considerably the yield 
of hay, and also to a marked degree the proportion of nitrogen 
compounds (protein) in the crop, especially where the larger 
quantities of nitrogen were used. Thus the use of nitrogen 
proved to be economical as affecting the amounts and conse- 
quently the commercial value of the crop, and still further so 
affecting the feeding value. On the whole, the most eco- 
nomical returns were made by the plots containing nitrate of 
soda at the rate of 320 pounds (nitrogen 50 pounds) per acre. 
In the experiments with corn the efficiency of nitrogen in 
the fertilizer in increasing the yield of the crop was not so 
marked as it was in the experiments with mixed grasses. 
While in the experiment on the grasses the yield from the use 
of 75 pounds of nitrogen per acre was considerably greater 
than the yield from the use of 50 pounds, in the experiments 
on corn the average yield with 75 pounds was very little more 
than with the use of 50 pounds of nitrogen per acre. In these 
experiments the most economical results were from the plots 
upon which 160 pounds of nitrate of soda (25 pounds of nitro- 
gen) were used. These results seem. to indicate that, in the 
use of fertilizers on corn, under such conditions as those in these 
experiments, the most economical amount of nitrogen ranges 
between 25 and 4o pounds per acre (equal to 160 to 250 pounds 
of nitrate of soda). In all the experiments with corn the 
proportion of the nitrogen compounds (protein) in both the 
seed and the stover was considerably larger in the crops from 
the plots upon which nitrogen was used in addition to the 
mixed minerals than it was in the crops from the plots upon 
which only mineral fertilizers were used. In these experi- 


