A Study of Colorado Wheat 
39 
The above series, though consisting of fewer members than 
might be desirable, shows the same effects upon the relative amounts 
of the ash constituents as in 1913, when we analyzed 12 instead of 4 
samples of straw as in 1915. The specific effects of the nitrate were 
to increase the calcium, potassium and magnesium and to depress 
the silicon; we see the same features in the above results. In 1913 
it produced no appreciable effect upon the amount of phosphorus. 
The check plot was of course adopted as our standard. In the re¬ 
sults of 1913, we observed that the application of phosphorus and 
also that of potassium tended to depress the phosphorus in the plant. 
We observe the same tendency in 1915. While the nitrate depressed 
the silicon, it increased the potassium, calcium and, in a less degree, 
the magnesium. The net result, however, was to increase the ash. 
The increase in 1915 is very slight, so slight that one can scarcely 
claim it to be satisfactorily decisive. If we compare the amount of 
these constituents for the two years, we will find it from 0.340 to 1.0 
percent lower in each of the four samples than in 1913. On looking at 
the individual constituents we observe that the potassium suffers 
approximately one-third of this depression, though all of the ash con¬ 
stituents participate in it. 
The weather conditions have already been given in some detail. 
It has been stated that the plants were kept wet a great portion of. 
the time. Whether this is the cause of the lower ash constituent or 
not, it is a fact and seems to me the probable cause. 
In considering the nitrogen compounds in the plants we had 
two series of effects, one of which we attributed to the fertiliz¬ 
ers and which was consistent throughout the two seasons. The 
other we attributed to the weather conditions. In addition to these 
two series of results, which seemed to run parallel up to the end of 
July, we had a third series of results which was not consistent at all 
for the series of samples taken after 30 July in the respective years. 
These results I believe to have been effected by the action of the rust. 
The results obtained by the study of the ash constituents of the 
plants in the two years are in harmony with those obtained by that 
of the nitrogen compounds up to the end of July, the latest date to 
which our work on the ash constituents can be applied. 
