21 
Nitrogen Fixation 
In some cases there is no question about the occurrence of sodic car¬ 
bonate in dark soils about old clumps of greasewood, but in this 
case the occurrence of the nitrate in dark, brown soils and the very 
dark color often noticed in the soil about these old clumps suggests 
the question whether the greasewood has anything to do with this 
occurrence. I found a very marked case of a mass of dark soil where 
such a clump had died and which was evidently very rich in alkali. 
This was quite near an area where I knew that nitrates occurred 
in large quantities so I thought it worth while to test the matter. 
The result was that the soluble salts found to be present were the 
sulfate 35.248 per cent, carbonate 37.065 per cent, and chlorid of 
sodium 27.687 per cent, with only a trace of nitric acid. This was 
the result expected except that the trace of nitric acid was unlooked 
for under the conditions. Apropos to the occurrence of nitrates 
in alkalis we have found small quantities of nitrates in others than 
the one given above but we have not found them always present. 
Alkalis from these districts may be entirely free from nitrates. 
The samples so far given have been of soils or ground waters, 
the localities of which I have not given and I have purposely avoid¬ 
ed giving names. I conceive that the circumstances require that I 
should do this. I have been requested again and again not to pub¬ 
lish the names of owners and places and I believe that it is just 
that I should not, for while it looks, in many cases, desperate for 
the future, conditions may change. Some means of remedy may 
be found whereby what now seems an inevitable result may be 
avoided. 
I have seen instances of these occurrences of nitrates near the 
southern and within 40 miles of the northern boundary of Colorado 
and likewise from its eastern to its western boundary. The analyses 
already given and those to be given, represent many sections, but it 
is not to be inferred that all or any more than a very small per¬ 
centage of the agricultural lands of Colorado are in the least en¬ 
dangered. While the matter is serious enough, it by no means 
amounts to a justification for evil forebodings. I am not at this 
time prepared to state how. we will combat this condition, but I 
believe that there will be some way. These remedial questions are 
for the immediate future; the trouble itself has, as yet, only been 
pointed out. 
I will give some cases in a general way but must avoid names 
and places. A small piece of land, a sandy loam, near and some 
12 or 15 feet above the river has a dark brown color and has not 
been productive for several years. This land has received good 
cultivation, the application of much barnyard manure, and excessive 
irrigation in the hope that the*“black alkali" would be washed out. 
This ground is not absolutely barren but some spots in it are nearly 
