I 
A Study oe Colorado Wheat 
39 
crop should diminish. Our results, taking stems, leaves and heads 
separately, agree with this statement. Of the sixty samples of 
leaves and stems given, there are only two instances in which we 
find any departure from this. These are found in the stems and 
leaves of one set of plants taken on 25th July in which, for some 
reason, we have high results. The heads as here given include the 
kernels and here we find an increase in the total nitrogen. When 
the period of ripening sets in we observe a rapid decrease in the 
amount of total nitrogen present in the stems and leaves, which is 
evidently not compensated by the increase in both the weight and 
the percentage of nitrogen in the heads. Wimmer, in the article 
already referred to, after pointing out the similarities and differ¬ 
ences between the results obtained with barley and spring wheat 
says in regard to the total nitrogen in spring wheat at harvest time, 
“But here also, we find at the final harvest only 80.66 percent of the 
maximum amount of nitrogen previously appropriated.” 
What is true of the total nitrogen is also true of all the several 
forms of nitrogen. The one exceptional sample, already mentioned 
in connection with the total nitrogen, is consistent with itself 
throughout, i. e., all forms of nitrogen are relatively high. There 
is one sample that is somewhat lower than we would expect and 
this, too, is, in the main, consistently low throughout. These fea¬ 
tures, though interesting, did not constitute the question that we 
set out to determine. This question was—what effects, if any, do 
the individual fertilizers produce upon the composition of the plant 
and wheat. 
Of late years, great stress has been laid upon the assumed fact 
that climatic conditions rather than the soil conditions constitute 
the principal factors in determining the composition and character¬ 
istics of the wheat grown. Our direct purpose is not to combat this 
idea, but to determine what the effects of nitrogen, phosphorus and 
potassium really are under our Colorado conditions. 
It is too evident to need statement that there are fundamental 
conditions of climate and of soil fertility requisite to the growth of 
a crop of wheat and we cannot eliminate these. All that we can do 
is to change the relative supply of nitrogen, phosphorus or potas¬ 
sium under identical conditions of climate, using the same variety 
of wheat. 
In making the preceding statement, I have the following con¬ 
sideration in mind: It is not just to compare samples of wheat 
taken on a given date unless they are of the same variety or it can 
be proven that they are in the same stage of development which 
would be exceedingly difficult to establish for different varieties. 
Our experience in 1914 with the two varieties. Defiance and Red 
