y6 The: Colorado Experiment Station. 
and a neutral or an alkaline medium. The temperature and alka¬ 
linity prevail in this section and the only factor which is lacking 
is the moisture to bring about the formation of nitrates. The cor¬ 
rectness of this view is indicated by the occurrence of the brown, 
greasy-looking spots along the irrigating ditch in a neighboring 
section of the country, where the land is similar though it is still 
native prairie. The conditions are not well enough known to 
justify definite assertions pro or con in these cases. I have not 
permitted myself to make any prophesises but simply to record 
the facts as I see them. It would, however, be very interesting to 
be able to watch the developments in this section for five years if 
it could now be supplied with an abundance of water for irrigation 
and we could grow a series of crops on these lands. This experi¬ 
ment, while altogether too big a one to be undertaken by an indi¬ 
vidual, will in all probability be made and while I cannot hope to 
be able to study it in detail, I do hope to be fortunate enough to be 
able to follow it in a general way. It will certainly be instructive 
to those who shall see it. 
DISCUSSION 
I have given a large number of cases but each case, with very 
few exceptions, represents different conditions—not only different 
from one another, but different from the conditions given in Bul¬ 
letin 155. I have endeavored to give different conditions and at 
the same time widely separated localities and samples representative 
of large areas. The aggregate area described in Bulletin 155, was 
between eighty and one hundred acres. The area described in 
this bulletin aggregates more than three hundred acres, and does 
not include any of that described in Bulletin 155. This is only a 
very small part of the total area involved in the state. So far as its 
distribution throughout the state is concerned the areas given repre¬ 
sent nine counties, extending from the Kansas boundary to that of 
Utah and from the Cache la Poudre to the Arkansas river, and 
even further south, to the New Mexican boundary. 
The total percentage of the irrigated or cultivated lands af¬ 
fected by this trouble, to the extent of the instances given, is more 
considerable than we might wish, but it is not a large percentage of 
the whole, still if we consider it in square miles and bear in mind 
the value of the lands affected, as estimated by the owners, it be¬ 
comes a very serious matter. The four hundred acres described 
in this and in Bulletin 155 are representative of large districts, 1 
think that as a very conservative estimate we may state the districts 
affected as aggregating from three hundred to four hundred square 
miles. In a large portion of this territory the conditions are very 
bad. The most serious feature is that these very bad portions may 
only represent extreme developments of a general condition which 
