EFFECT OF NITROGENOUS FERTILIZERS. 157 
ments also the use of nitrate of soda was more economical than 
that of sulphate of ammonia. 
The number of experiments with oats was not sufficient to 
warrant deductions as to the quantities or kinds of fertilizer 
materials supplying nitrogen that may be used on that crop 
with most economy. In all the experiments in which nitrogen 
was used the yield was markedly increased. In general, the 
results are similar to those obtained with mixed grasses and 
corn. The effect of the nitrogen on the composition of the 
crop, especially of the seed, was quite marked. This was most 
noticeable on the plots to which nitrate of soda was applied. 
The effect of the nitrogen of the fertilizer in increasing the 
nitrogen compounds (protein) of the crop was more noticeable 
in the experiments with distinct species of grasses than in any 
of the other experiments. The average composition of all the 
_ kinds of grasses experimented upon gives the following per- 
centages: in grasses from plots having only mineral fertilizers 
(phosphoric acid and potash), 7.4 per cent. protein; in those 
from plots having nitrogen at the rate of 25 pounds per acre, 
in addition to the minerals, 9.7 per cent. protein; and in those 
from plots having nitrogen at the rate of 75 pounds per acre, in 
addition to the minerals, 12.5 per cent. protein. This means 
that a ton of the crop from the plots upon which nitrogen was 
used at the rate of 75 pounds per acre would contain (60 per 
cent.) I20 pounds more protein than would a ton of the crop 
from the plot upon which minerals only were used, showing 
that the nitrogen of the fertilizer greatly increased the value of 
the crop independently of its effect upon the yield. 
With soy beans (seed) and cow peas (plants grown 
for fodder) the results were very different from those with 
cereals and grasses. The nitrogenous fertilizers had very little 
effect upon either the yield or the composition of the crops. 
That is to say, these legumes showed very little increase, either 
in yield or in the percentages of protein, resulting from the 
use of nitrogen in the fertilizer. The yield of dry matter in 
the crops from the nitrogen plots was but very little larger 
than in the crops from the mineral plots. In protein also the 
yield was but slightly greater in the crops from the nitrogen 
plots. 
A comparison between relative yields of dry matter and of 
protein in the grasses and corn on the one hand, and in cow 
peas and soy beans on the other, is given in the following table, 
taking the yield from the mineral plots as a basis. 
