Alkalis In Colorado 
21 
of nitrates in a wheat or oat field may be very small indeed—one-fifth 
or even one-eighth of the amount just given. The important question 
in this connection is, Where does the nitrogen in the nitrates come 
from. If we have the nitrogen given in decaying nitrogenous matter 
the processes by which it may be changed into this form, the one best 
fitted for the use of the plant, are known. The students of this sub¬ 
ject have to deal with very small quantities compared with the mass 
of the soil or in comparison with the quantities in which some of the 
other important constituent are usually present. In a cropped field, 
for instance, it is not uncommon for us to find so little as 24 pounds, 
or even less, in an acre-foot of soil, and the plants, too, deal with very 
small quantities of these nitrates. I added 250 pounds of nitrate of 
soda to the acre and injured my wheat crop. These 250 pounds of 
nitrate of soda contained only about 40 pounds of nitrog'en. Perhaps 
the average reader will appreciate this more fully if we state this 
another way, i. e., that I spoiled my crop by adding 10 pounds of ni¬ 
trogen . for each 1,000,000 pounds in the top foot of soil. The 
quantities of nitrogen, then, that we have to deal with are not big 
like the quanties of sulfate or carbonate of soda, and still smaller in 
comparison with the water-soluble portion of the soil. The soil of 
my wheat field contained a little over 3,800 pounds of soluble salts in 
each million pounds of soil and yet the addition of only 10 pounds of 
nitrogen as sodic nitrate injured my crop. It did not kill the plants, 
but they fell down and did not ripen as they should and the crop was 
short. I have done this now some fifty times, always with the same 
result. 
Too Much Nitrate Is Injurious 
These results show us that while the nitrates are necessary for 
the plant's growth and fruiting, it is easy to get too much for the pro¬ 
duction of good, strong, healthy and productive plants, in fact, it is 
easy to get enough to kill the plants outright. 
Nitrates Cause of “Brown Spots” 
It is a fact, on the other hand, that we find areas, some of them 
very small and others very large, where these nitrates are very abun¬ 
dant, equivalent in some extreme cases to 56,820 pounds in a million 
pounds of the soil. Some of these areas are very sharply defined with 
only two things to show them to be different from the rest of the land. 
These two things are; First the fact that there is nothing growing on 
them, and second that they are almost always brown. They some¬ 
times look as though they were wet and have a slight crust on the top. 
Under this crust they are often mealy and if there is no crust the sur¬ 
face may be so mealy that it is cuffed uc. 
