A Study of Colorado Wheat 
33 
in the leaves, and the part played by the latter in the economy of the 
plant may be greater than that of the stem, still the general effects 
of the fertilizers and of the seasons may be quite clearly seen in 
this portion of the plant, so we will consider the stems only, whereby 
we sacrifice nothing of the truth and gain much in brevity. 
In the samples of the stems taken in 1913 we see that the total 
nitrogen is increased by the application of nitrates, and while this 
increase is not proportional to the amounts applied to the different 
sections of land, it is true that up to the end of July the stems of 
those plants grown with the largest application of nitrates contain 
the highest percentage of nitrogen. This relation was no longer evi¬ 
dent when the plants have become so nearly ripe that it was no 
longer possible to separate the stems and leaves. It has elsewhere 
been stated that the sheaths are, fo,r the most part, taken with the 
stems. 
Tlie amount of total nitrogen in the stems during the season of 
1915 is much smaller than in 1913, but those grown with the appli¬ 
cation of nitrates are uniformly higher than those grown without it. 
The total nitrogen in the stems in 1915 is roughly equal to three- 
fourths of that present in 1913. This is true of the nitrogen in the 
stems np to the end of July only; from this time till harvest the 
stems, with whatever leaves were left, in 1915, contain more nitrogen 
than they did in 1913, while the heads contained very much less ni¬ 
trogen than in 1913. In other words, the nitrogen was not trans¬ 
ferred from the stems and leaves to the heads in 1915 to the same 
extent that it was in 1913. The ripening period did not produce the 
changes taking place during this period in the same thorough man¬ 
ner in the former as in the latter season. 
These facts divide our considerations in two parts. The first 
part brings us to the beginning of the ripening period, and the sec¬ 
ond consists of this period. This is a natural and common division, 
which we observed in writing Part I (Bulletin 208), but for en¬ 
tirely different reasons than now. 
The facts that we have presented show that the effects of the 
nitric nitrogen applied to the plots are of the same character and 
persistent throughout the two very dissimilar seasons. The same 
is true of the phosphorus and potassium, but in so far as the nitrogen 
content of the plant may be relied upon as an indication, the compo¬ 
sition of the plants were quite unlike, all parts examined, stems, 
leaves and heads, were richer in total and proteid nitrogen in 1913 
than in 1915, without regard to the amount of this element in the 
form of nitric nitrogen at the disposal of the plant. 
The effects of phosphorus and potassium are, as in 1913, so in¬ 
definite and irregular that the small variations observed are not en- 
