Fixation ot Nitrogen in Colorado Soils ii 
A\AIiYSIS OF VVATKK-SOIAJBI.E, Soil laboratory No. 1M54 
Water-soluble equaled 7.81 percent of air-dried soil. 
Percent 
Calcic sulfate 7.823 
Calcic chlorid 22.716 
Calcic nitrate 21.551 
Mag-nesic nitrate 38.102 
Potassic nitrate 6.784 
P7xcess as sodic oxid 3.024 
100.000 
These soil samples were taken relatively close together, 
the most distant pair being about a mile from one another. This 
land shows no efflorescent salts, it is simply black and more or 
less shiny; in some places it is a little mealy. 
SALTS IN SOIL— EXTRACTS DIFFERENT FROM 
ORDINARY ALKALIS 
The analyses show that the salts present in these soils are 
wholly different from those in our ordinary alkalis. The small 
amount of sodic salts present is as remarkable as the very large 
percentage of nitrates and chlorids which are present as calcic 
and magnesic salts. The analytical results are such that there 
can be no question in regard to the order of combining the 
elements to form salts, there is no choice. The salts present 
are essentially the chlorids and nitrates of calcium and mag- 
nesium, with more potassium than we usually find in such e.x- 
tracts and only very small amounts of sodic salts, whereas, it 
is generally the case that the sodic salts are very strongly pre- 
dominant. That there should be no soluble carbonates in the 
presence of such excessive quantities of calcic chlorid is what 
we should expect, but there is no reason why the sulfates of 
calcium and sodium should not be present. These sulfates are 
abundantly present throughout the Poudre Valley and in almost 
every other portion of the State. In fact, the sulfates are the 
characteristic salts of our alkalis. There is no property of the 
chlorids that would militate against the presence of the sul- 
fates of either calcium or ma^esium. We have one section of 
country not as yet discussed in any of our publications where 
we have calcic chlorid present as an important, and in some 
samples the predominant constituent of the soluble salts. 
How these quantities of calcic and magnesic chlorids have 
been formed or can be present is by no means clear. The alkalis 
in the Poudre Valley carry magnesic sulfate to a larger extent 
than those from other sections of the State. The presence of 
this salt is shown by all of the analyses of alkalis and also 
ground-waters that we have published. Why these sulfates 
