
Sa. 
ns 
FIELD EXPERIMENTS WITH FERTILIZERS. IOI 
In the case of corn, in which similar results have been noted, 
the smaller yield with the sulphate has been explained as pos- 
sibly due to an acidity of soil resulting from the repeated appli- 
cation of this material to the same plots year after year. ‘The 
exception in 1898 noted above may, perhaps, be the result of 
the exceptional rainfall of 1897, and heavy rains also in 1898, 
which may have washed considerable of the surplus acid out of 
the soil at that time. No experiments have been made by the 
Station to test the advantages of lime upon the sections of the 
sulphate of ammonia plots upon which cow peas are grown. 
The amounts of nitrogen in the fertilizers and the proportions 
of protein in the crob.—F rom Table 44 below, giving the percent- 
ages and amounts of dry matter in the crop at harvest and the 
percentages and amounts of protein in the dry matter, it will 
be seen that in many instances the percentages of protein are 
larger in the crops from sections of plots without fertilizers than 
in those from sections of plots with fertilizers. ‘This has been 
noticed in the case of corn also, and may, perhaps, be due to 
premature ripening of the plants on the sections without fertili- 
zer. It has been shown by analyses that the proportion of 
protein is larger in immature, or “‘ poor’’ corn, than in mature, 
Peroood.. Corn, 
From the results given in Table 44 there appears to be but 
little relationship between the quantity of nitrogen in the fer- 
tilizer and the proportion of protein in the crop. In the 1898 
experiments the percentage of protein was higher in the aver- 
age of the crops from the sections of the two mineral plots than 
in the crop from sections of any of the plots with nitrogen. In 
the 1899 experiments, however, there appeared to be some 
increase in the proportion of protein in the crop accompanying 
the increase in the nitrogen in the fertilizer, as may be seen 
by comparing with each other the percentages of protein in the 
crops from sections of plots 7, 8, and 9, with respectively 25, 
50, and 75 pounds of nitrogen in nitrate of soda, and also those 
from sections of plots ro, 11, and 12, with like amounts of 
nitrogen in sulphate of ammonia. In the experiments with cow 
peas, as a whole, the increase in the protein in the crop which 
accompanies the application of the nitrogen in the fertilizers, 
as shown by figures for percentages and yields of protein per 
acre, has been smaller and less uniform than in the experiments 
with common grasses. 
