The Fixation oe Nitrogen. 
47 
•occurrence of nitrates in very large quantities in this section for 
two years, but this and some others were new and wholly unex¬ 
pected occurrences. I took two samples of soil, one to a depth of 
three inches, No. 977, the other from the fourth to the fifteenth 
inch inclusive, No. 978. The water-soluble in No. 977 equalled 
2.92, in No. 978, 0.54 percent. 
ANALYSES 
LVII 
Water-Soluble 
laboratory 
No. 977 
Percent 
LVIII 
Water-.Soluble 
laboratory 
No. 978 
Percent 
Calcic sulfate . 40.37 6 
Magnesic sulfate . 22.470 
Potassic sulfate . 3.686 
Sodic sulfate . 3.606 
Sodic chlorid . 23.930 
Sodic nitrate . 4.902 
Iron and Aluminic oxid. 0.196 
Silicic acid . 0.834 
50.910 
15.972 
8.639 
16.814 
6.039 
Trace 
0.288 
1.338 
100.000 100.000 
Sample No. 977 gives us 65.5 pounds of nitrates available to 
each such tree as this, assuming that the roots occupy a circle of 
ground forty feet in diameter and that the whole of the nitrates in 
the top three inches, is by any means brought within the feeding 
area of the roots. 
As I have elsewhere stated I do not know how small a quantity 
of nitrates will suffice to produce a burning of the leaves. 1 he 
tree in question was burned, but scarcely enough to produce serious 
injury. Our observations would have to be continued into, if not 
through, the season of 1911 to form any reliable judgment in 
regard to this point. 
This land is so located that it is difficult to believe that these 
nitrates could have been washed from any adjoining lands, and if 
they were brought to the surface by capillary attraction they must 
have existed in the soil itself, but our analysis of the soil taken 
from the fourth to the fifteenth inch inclusive shows only a trace 
of nitrates in the aqueous extract. It is also out of the question 
to think that the irrigating water, snow water, might contain 
enough nitrate to permit of such a concentration as we find even in 
this case. These points are mentioned in this connection because in 
many cases the conditions legitimately admit the question of trans¬ 
portation from higher lands either by seepage or washing. That 
is, they could fairly be raised whether they actually apply or not. A 
case in point, i. e., Case 8, has been presented in considerable detail 
to enable the reader to judge for himself whether washings from 
the higher lands or the seepage from them could possibly account 
for the nitrates occurring in the land described. The presentation 
of the analyses given is itself a proof that I have most seriously 
