EFFECT OF NITROGENOUS FERTILIZERS. I59 
(2) the legumes are benefited largely and chiefly by the use of 
mineral fertilizers; (3) the legumes, which take much of their 
nitrogen from the air and leave a great deal behind in their 
roots and stubble and otherwise in the soil for the use of plants 
that come after them, should be grown in rotation with crops 
of the grass family which feed heavily upon the readily available 
nitrogen of the soil; (4) all crops need the mineral fertilizers. 
The cereals and grasses respond also to nitrogen. 
DETAILED DATA OF THE EXPERIMENTS. 
The following Tables, 25 to 39, give in detail the data from 
the experiments with the various crops grown upon plots 
treated with different kinds and amounts of fertilizers. The 
composition of each crop (except the pure species of grasses) 
is given in two tables, both based upon the water-free substance 
in the crop. The first table shows the percentage of protein 
(nitrogen x 6.25), fat, nitrogen-free extract, and ash contained 
in the crop at the time of harvesting, as determined by chemical 
analysis; and the second table shows the yields of nutrients per 
acre, computed by the use of the percentage composition. 
The grasses were generally harvested at, or soon after, the 
time of blossoming, and in the case of field crops, were sampled 
immediately after the total weight of the crop was determined. 
Large samples of 5 to 8 pounds of hay, or about 10 to 35 pounds 
*of grass, were taken for the main sample. These were cut in 
a feed-cutter into pieces an inch or so in length and well mixed. 
_ From the material thus mixed were taken sub-samples of 500 
to 1,000 grams of hay, and 1,500 to 4,000 grams of green crop, 
which were partially dried in a steam dryer. At the laboratory 
these were ground into a finely pulverized condition prepara- 
tory to taking the final sample for analysis. 
In much the same way the corn stover was sampled imme- 
diately after the corn was husked and the crop weighed. A 
large sample, about one peck, of the merchantable corn (ears) 
was selected from each plot, the corn was shelled off at once 
and the proportion of grain determined. The grain was then 
partially dried, and later finely ground, and the samples stored 
in tightly sealed jars until the analyses could be made. . 
” 
