A Study oe Codorado Wheat 
4i 
Second, the application of nitrogen to the soil increased the 
nitrogen in the plant quite materially over that present in the plants 
grown on the check plots. This was true for each of the different 
applications made. 
Third, the application of potassium depressed the amount of 
nitrogen present in the plants below that present in those grown on 
the check plots. 
These facts hold, but not to the same extent, for the period of 
ripening of the grain. These statements are also applicable to the 
heads, though in this case we have a continuous increase in the 
amount of nitrogen present instead of a decrease as in the other 
parts of the plant. As the plants approach maturity, the differ¬ 
ences in the amount of nitrogen present in the heads from the 
plants grown on the different plots becomes less certain. This is 
especially true of those from the plots which had received applica¬ 
tions of phosphorus or potassium and of those from the check 
plots. The plants that were grown with the application of nitrates, 
remained richer in nitrogen in all parts throughout the period of 
investigation than the other plants, without any material exception. 
THE ASH CONSTITUENTS OF PLANTS. 
It is not proposed to follow the movement of the ash con¬ 
stituents in the plant, but simply to endeavor to determine in what 
sense and degree the amount of these constituents may be affected 
by the fertilizers used in our experiments. The observations given 
in this place do not include the kernels, only the plants. It is as¬ 
sumed that the amount of these constituents reaches a maximum at 
a certain stage in the development of the plant and from this time 
on decreases till the plant is mature. This is the case with the in¬ 
dividual constituents in a very marked degree, except in the case of 
phosphorus, which recedes by only about one and one-half or two 
percent. That the ash constituents in the growing plant must be 
present in a soluble condition seems necessary in order that they 
should function, as we suppose them to do, and also that they 
should move out of the plant and return to the soil. We assume in 
this statement that these ash constituents return by the way of the 
plant itself and not by exudation or washing out by rain or by the 
dying and falling off of parts of the plants. With these questions 
we have nothing whatsoever to do, but simply to inquire in what 
sense and degree our fertilizers may affect them. For this purpose 
a number of samples were examined, but not all in the same man¬ 
ner. The first method used was to char the air-dried plant, extract 
with water and subsequently burn. This method gave the follow¬ 
ing results: 
