The Fixation of Nitrogen in Colorado Soils 9 
to 28 parts per million under ordinary conditions, and rises to 
106 parts per million under special conditions, while the chlorin 
varies from 80 to 971 parts per million without any relation what¬ 
soever to the amount of nitric nitrogen; the same is true, too, of 
the total solids, the sulfates and carbonates, so far as the latter 
have been given. 
The accepted origin of the alkalis has already been indicated 
and is, I believe, of universal application. In regard to their 
presence in the shales perhaps the sulfids of iron ought to be con¬ 
sidered as a possible agency contributing to their formation. 
A question may be raised as to whether there are any occur¬ 
rences of nitrates in the immediate vicinity. I think the nitrates 
appearing in well three owe their presence in such abundance to 
formation on the surface of the soil, but we will waive this point 
and give an analysis of a surface-soil from a typical “brown 
spot” where there is no unusual amount of alkali and whose limits 
are as distinctly marked as the margin of this printed page. The 
sample is a surface one, taken not more than one inch deep. The 
surface of this spot was moist due to the deliquescent character of 
the magnesic and calcic nitrates. The soil proper is a red, 
gypsiferous clay. 
One of the effects of the presence of the nitrates in soil was 
set forth with emphasis in Bulletin 155, i. e. they brought about a 
muddy condition of the soil, a deflocculated condition which re¬ 
tained the water persistently. The statement was made, that while 
a certain soil was a veritable mud at two to two and one-half feet 
below the surface, no proper water-plane was met with at a depth 
of six feet; and in another which was muddy quite to the surface, 
we found no proper water-plane at six feet and had to wait nearly 
two hours to collect two gallons of water. It is easily conceivable 
that the presence of highly deliquescent salts, such as calcic and 
magnesic nitrates formed in the surface soil, should change the 
action of capillarity in the underlying soil and bring about ex¬ 
cessive surface deposition of the salts already present in the mass 
of the soil. In the case here presented the surface-soil contained 
11.56 percent of substances easily soluble in water, and the soil 
when dried in the air bath and exposed to the atmosphere, quickly 
becomes so moist that it forms a coherent mass when pressed be¬ 
tween the thumb and finger. This spot occurs on the road side. 
The land here is not seeped and is not alkali land like the preceding. 
This sample is chosen because it is located in the same section of 
country as the land just discussed, and no explanation can be 
offered that the differences are due to location and general condi¬ 
tions and not to the causes that I have assigned, i. e. to excessive 
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