24 The: Colorado Experiment -Station. 
statement that both water and alkali may be quite abundant and 
the land still be productive. These are very undesirable conditions 
but they alone are not so fatal as some people would have us 
think. In all events they constitute problems distinctly different 
from the nitre problem, and are not so closely related to it as even 
I at first thought. My original description of these occurrences 
of nitre showed that I considered it as dependent upon a constant, 
optimum supply of moisture. This condition is met with near the 
outer edges of wet places. The nitrates do not appear where there 
is a great excess of water. On the other hand they are not confined 
to places which are seeped, of which fact the orchard in question, 
No. 8, is a good example, as is also Orchard No. 7. In fact, 
Orchards 1 and 2, Bulletin 155, are the only cases given in which 
an excessively wet condition of the soil was observed but no proper 
water table was found in these at a depth of six to six and a half 
feet. Such, then, are the conditions surrounding this orchard No. 
8, and the little garden tract immediately north of it. I have 
already stated that the soil is sandy and the section at the river 
bank, which practically forms the southern boundary of the field, 
shows a section of twelve to fifteen feet, the upper six or seven feet 
of which is sand while the lower portion is a coarse river gravel. 
A sample of surface soil, taken two inches deep in April, 1909, gave 
4.42 percent of the air-dried soil as soluble in water. Sample No. 
S75 contained 10.86 percent of salts soluble in water. 
ANALYSES 
XXV 
XXVI 
Water-Soluble 
Water Soluble 
laboratory 
laboratory 
No. 772 
No. 875 
April, 1909 
Nov, 1909 
Percent 
Percent 
Calcic sulfate. 
. 35.266 
24.810 
Magnesic sulfate . 
. 3.197 
3.238 
Magnesic chlorid . 
. 14.673 
15.235 
Potassic chlorid . 
. 2.109 
1.911 
Sodic chlorid . 
. 33.841 
50.704 
Sodic nitrate . 
. 10.508 
3-944 
Iron and Aluminic oxid . 
Sodic silicate . 
. 0.406 
0.158 
100.000 
100.000 
We have in No. 772 the nitrates equivalent to 0.464 percent 
of the top two inches of the soil, equal to 3,096 pounds or one and 
one-half tons of nitrates per acre taken to a depth of two inches or 
at the rate of nine tons per acre-foot. In No. 875 we find the 
sodic nitrate equal to 0.424 percent of the surface soil, giving us 
practically the same amount of nitrates per acre as No. 772. 
