6 
Colorado Experiment Station 
also caused the death of stock, especially when they were first 
brought in from the range. 
This section has been brought under irrigation within com- 
paratively recent years. It is certainly not yet 25 years since 
this happened. The death of the cattle, due to the drinking of 
this well-water, occured 6 or 7 years ago and a well-water, in 
what is known to me as the Boon place, had caused the death 
of some cattle each year for some years before this, so these 
conditions had established themselves in less than 15 years 
after the section had been brought under irTigation. It must 
not be inferred from this statement that there is any proof at 
all that irrigation has any proven, direct, and necessary con- 
nection with the formation of these nitrates. A certain amount 
of moisture is necessary. Irrigation plays no other part than 
to supply this moisture. Previous to the incident of the killing 
of the cattle by this water, the occurrence of nitrates in this 
particular section was unknown to me, though I knew of their 
occurrence in other sections of our immediate neighborhood. 
superficial examination of this land sufficed to convince me 
that it presented another instance of a remarkable amount of 
nitrates in the surface soil. 
A few years later other samples of well-waters carrying 
nitrates were brought in to us. This occurred so frequently 
that it seemed to be worth the while to study the section to 
ascertain the relation existing between the occurrences in well- 
waters and in the surface soils. This attempt has led to the 
preparation of this bulletin, whose object it is to give the gen- 
eral facts of this, heretofore, undescribed occurrence of nitrates ; 
to present the relation between the occurrence of these salts in 
the soil and the well-waters; and also to present in so far as 
possible the composition of waters obtained from deep wells. 
PLAN OF STUDY 
The plan of study was in the first place to gather samples 
of surface soil and of waters from shallow wells, on an east and 
Avest line across the district, IG miles, and also on a nortli and 
south line through it, 13 miles. In the first line Ave have the 
section of one valley and the Avestern portion of one and the 
eastern portion of a third one. The north and soutli line gaA e 
us a section of the central valley. This preliminary Avork re- 
vealed the fact that Ave had to do Avitli only one principal area 
on the east and Avest line which Avas rather more than 2 miles 
Avide, but on the iiorlli and south line it Avas broken into su!)- 
ordinate areas for tlie greater portion of the line. We altm*' 
