4 
Colorado Experiment Station 
quantities of nitrates produce a big effect upon the growth of the plant 
and the character of the grain. The nitric nitrogen usually present in 
our soils is adequate to the production of good crops but not always 
adequate to the production of the best quality of grain. This is the 
reason why the application of sodic nitrate affects the character of the 
grain but in our experiments has not increased the yield to any marked 
extent; on the contrary, we have in many instances depressed it. 
EFFECTS OF IRRIGATION 
As irrigation is an indispensable portion of our practice, we have 
to determine the water supply necessary to produce the best crop and 
the effect of the water upon the character of the grain produced. 
Our results show that if the plants be brought to the period of 
early head or to the time when they are well advanced in the boot in a 
healthy manner and are then irrigated liberally no further irrigation is, 
in ordinary seasons, necessary. Subsequent irrigation in our experi¬ 
ments proved to be useless in every respect, i.e., it neither increased the 
crop nor influenced the character of the grain, while the soaking of the 
ground exposed the crop to some danger. 
The effects of water upon the quality of the grain depends upon 
conditions. Excessive water applied to the soil does not affect in any 
material degree the composition of the grain but if the plants be kept 
wet and the weather be dull and warm the crop will suffer greatly, in 
fact, will probably be ruined. 
The leaching effects of water upon the soil may in some instance 
be a danger but in our experiments we could not discover any bad 
efl'cets due to this cause. 
As our soils contain a total supply of 2.25 to 2.5 percent of potash 
of which, roughly, one-quarter is soluble in dilute hydrochloric acid, 
we have an abundant supply of this element for many years. This 
means that we have from 22,500 to 25,000 pounds of potash in each 
million pounds of soil with from 5,600 to 6,250 pounds soluble in di¬ 
lute acid at the present time. These quantities are so large that it does 
not matter wdiether we are quite right in tacitly assuming that being 
soluble in dilute hydrochloric acid is the same as being available to the 
] 4 ant or not. It is evident that the supply is verv abundant. 
NITROGEN OF PRIMARY IMPORTANCE 
We have given the cultural reason for stating that the supply of 
])hosphorous in this soil is adequate. As a matter of fact it is about 
three times as much as is considered adequate in a soil of similar 
composition. These analytical considerations indicate that the plant 
