FIELD EXPERIMENTS WITH FERTILIZERS. 45 
Thus it will be seen that on the sections without lime the 
average yield of shelled corn per acre was 44.2 bushels from 
plot 8 and 44.6 bushels from plot 9, while it was 46.7 bushels 
from plot 11 and 37.8 bushels from plot 12. 
To explain this decrease in yield from plot 12 it was assumed 
that on this plot on which the large amounts of sulphate of 
ammonia were used the acidity of the soil resulting from the 
accumulation of sulphuric acid residue became so great as to 
interfere with the growth of the corn. As already explained, 
lime was applied to correct this acidity. In the table above it 
will be seen that on the sections with lime the average yield of 
shelled corn per acre was 53.5 bushels from plot 8 and 53.7 
bushels from plot 9, while it was 50.3 bushels from plot 11 
and 53.9 bushels from plot 12. 
It will be noticed that the average yields from all the plots 
of both the nitrate of soda and the sulphate of ammonia groups 
was larger from the sections with lime than from those without 
it. This would seem to indicate that lime had some directly 
beneficial effect upon the fertility of the soil; possibly such as 
aiding in the nitrification of nitrogen compounds present in the 
soil. 
The experimental results apparently favor the hypothesis 
that the soil on the plot with the large quantity of sulphate of 
‘ammonia had become injuriously acid, and that the acidity 
was corrected by lime. The attested fact is that the yields 
were greater from all the plots in both groups, but that the 
lime had the greatest influence on the yield from the plot with 
the largest ration of the sulphate. 
The amounts of nitrogen in the fertilizer and the proportions of 
protein in the crop.—Tables to and 11 illustrate the effects of 
the nitrogen of the fertilizers upon the composition of the plant 
as determined by chemical analysis. They are intended espe- 
cially to show the increase in the proportion of nitrogen and 
thus of protein in the crop following an increase in the propor- 
tion of nitrogen in the fertilizer. The data included in these 
tables are the weights of the crop per section as harvested, and 
the percentages and calculated weights of dry matter and of 
protein per acre. In the last two columns of the table the 
yields of dry matter and of protein per acre are given in 
