44 
Colorado Experiment Station 
cause of the weakness or not. The following determinations of 
total silicon were made to ascertain whether and to what extent the 
silicon in the straw may be suppressed by an increased supply of 
nitrogen in the soil. 
SUPPRESSION OF SILICON IN STRAW DUE TO NITROGEN. 
Date of 
Nitrogen 
Moisture 
Silico'n 
Harvest 
Variety 
Lbs. per Acre 
Percent 
Percent 
Difference 
28 July, 1913 
Defiance 
120 
9.395 
1.656 
28 July, 1913 
Defiance 
None 
8.274 
1.817 
0.252 
31 July, 1913 
Red Fife 
120 
9.544 
1.029 
31 July, 1913 
Red Fife 
None 
7.564 
1.236 
0.207 
29 July, 1913 
Defiance 
80 
8.177 
1.190 
29 July, 1913 
Defiance 
None 
8.711 
1.649 
0.459 
6 Aug., 1914 
Defiance 
120 
9.802 
1.192 
6 Aug., 1914 
Defiance 
None 
9.533 
1.708 
0.516 
6 Aug., 1914 
Red Fife 
120 
9.724 
1.134 
6 Aug., 1914 
Red Fife 
None 
9.205 
1.391 
0.257 
6 Aug., 1914 
Kubanka 
120 
9.515 
1.169 
6 Aug., 1914 
Kubanka 
None 
9.550 
1.557 
0.388 
While there is in each of these cases a depression of the silicon 
in the straw due to the nitrogen applied it seems too small, espe¬ 
cially if we consider the large amount in the plant, to cause the 
softness and weakness noted. This statement considers only the 
question of the total amount of silicon present. It is possible that 
there may be a difference in the form in which the silicon ma^ be 
present due to the action of the increased supply of nitrogen. 
Further, there might be a difference in its distribution in the dif¬ 
ferent parts of the plant. Silicon for instance deposited in the 
glumes or in the blades of the leaves or in the upper portion of the 
stems would not tend to prevent lodging if the lower internodes 
were so deficient in silicon that they could not support the plants 
in an upright position. We assume in this statement that it is 
true that the stiffness of straw is due to the silicon in it. 
There is a decided difference in the tendency of the different 
varieties to lodge. The Red Fife has scarcely lodged at all on our 
plots even with the maximum application of nitrogen. The 
Kubanka has lodged some but not badly while the Defiance has 
lodged badly with the minimum application of nitrogen. That 
this is due to the nitrogen applied there can be no doubt for in 
every case so far (about twenty of them), the limits of the applica¬ 
tion of the nitrogen were sharply marked in the case of the Defiance 
by the lodging. The amount of silicon in the whole straw, how¬ 
ever, is fully as high as in the other varieties, so it would not seem 
to be a question of the total amount of silicon present. 
The effect of fertilizers upon the amount of silicon contained 
in the first internode below the rachis indicates that the Red Fife is 
influenced less than the Kubanka which is in keeping with the ob- 
