26 
The Colorado Experiment Station. 
Newly set trees, trees that have just come into bearing, and trees 
that are fifteen to twenty-five years old, in fact, trees of all ages, 
seem to suffer alike. It is not an isolated tree here and there that 
has died, but thousands, representing many acres of orchards in 
widely separated districts, have perished during the past two seasons. 
When one is brought face to face with facts of such tremendous 
economic importance as these, he can scarcely fail to be impressed 
with the deplorable condition of affairs, and is forced to the position 
that something out of the ordinary is taking place, and that it is not 
without a cause. 
With reference to the occurrence and distribution of the nitre 
areas, Dr. Headden gives the following* in Bulletin 155 of this 
station: 
‘This trouble was not confined to any one section, but was com¬ 
mon to several sections of the state. While it, in all probability, 
depends upon soil conditions, these conditions are met with in so 
many places that it is necessary to consider the condition rather than 
the soil itself. It sometimes occurred in light and sandy loams, and 
sometimes in clayey soils. It is sometimes in comparatively low 
lying lands, again in the low lying portions of higher lands, and 
again on the hillsides. The road side, a ditch bank, and the cul¬ 
tivated fields represent the range of places in which this thing may 
reveal itself. There is one thing common in all of its occurrences, 
namely, a brown color in the surface soil. This color is less marked 
in the sandy soils than in the so-called adobe soils. Perhaps this 
is due to the presence of the deliquescent salts on the surface of the 
adobe soils, or more probably to the color of azotobacter films.’ 
‘We find the nitrates present in soils, where there is a great deal 
of moisture, but in places where there is too much water, the nitre 
does not appear. In little valleys and saucer shaped depressions in 
which the lower portions are too wet, there is no visible alkali, then 
follows a zone where white alkali abounds and above this the nitre 
is formed. I do not mean to say that there may not be nitre mixed 
with the white alkali, but that the nitre in such cases appears on 
higher ground than that on which the white alkali usually appears. 
Furthermore, it is not intended that anyone shall infer that it is 
only in valleys and depressions that the nitre occurs.’ 
In driving through those districts which are suffering with this 
trouble, the most striking feature to one not conversant with the 
symptoms is the brownish, black and, to all appearances, wet condi¬ 
tion of the soil. This can be seen along both sides of the travelled 
road, and often extends to the irrigating ditch, or fence on either 
