The Fixation oe Nitrogen in Colorado Soils 31 
DISCUSSION. 
We have given the results obtained with the samples as taken 
without comment, in order that the reader may consider them in 
detail for himself, but even so it is quite impossible for him to make 
any reliable interpretation without a knowledge of the varied con¬ 
ditions that obtained at the different places, and at the same place 
from time to time, and particularly of the conditions which obtained 
at the time the samples were taken. I have already stated that 
these conditions in 1912 were decidedly less intense than in the years 
of 1910 and 1911. While this staement is intended as a general 
one, it applies specifically to three out of the four places given and 
to the fourth place, too, with the important modification that in 
preceding years no nitre spots could be recognized by us, but one 
spot was definitely located in this year. While this general state¬ 
ment is true, there were a number of places where this condition 
was much worse than in former years. In fact, it appeared in this 
year, 1912, in places where it had not previously appeared, or if 
previously present it had not become sufficiently intense to produce 
noticeable injury. In one section of the State the trouble etxended 
very greatly, I call to mind one piece of land which in 1911 showed 
very little of this trouble, but the conditions in 1912 were very bad. 
In fact, the garden stuff planted on it was, to a large extent, a fail¬ 
ure. The water-plane in this land was from 5 to 8 feet below the 
surface. The soil was a fine, sandy loam. 
The first place chosen was, prior to 1909, an apple orchard. 
The trees had attained the age of 27 or 28 years, were large, and 
apparently healthy. There was but little premonitory burning 
which was not recognized as such until after the fatal attack which 
destroyed the orchard, that is, killed the trees in a few weeks. 
The following year it was planted to corn, the next year to canta¬ 
loupes, and last year, 1912, to oats. These crops have all been 
failures. The character of this soil, the location of the land, and its 
drainage, are all that can possibly be desired. The development of 
this trouble has ruined it, for the present at least. Samples taken 
from the surface of this land have shown the presence of from 
864 to 3,861 p. p. m. nitric nitrogen. These samples were not 
taken immediately after irrigation, and were taken in the summer 
season. The samples of soils presented were taken, those of the 
vertical section in October, and show that the top six inches of 
soil contain approximately 218 parts of nitric nitrogen, while 
the remaining fifty-four-inches sampled contained 106 parts. 
The surface portion is rich in chlorin. The surface six inches 
carry 1,863 parts of chlorin, the remaining fiftyfour inches 
