The Fixation oe Nitrogen in Colorado Soils 17 
giving the facts and not making any excuses for the data that we 
are about to present. 
Our plan was to collect samples from certain measured areas 
at stated intervals and observe the variations in the amount of 
nitrates and chlorids present and also to note the appearance of any 
brown spots” within these areas and the development of the 
nitrates in them. The lands chosen were supposed to be favorable 
for our purposes and were sufficiently varied in character to meet 
any objections which might be based upon the assumption of our 
being too strongly influenced in making the selection. Some of the 
land suffered a change in management during the period of our 
observations and we were deprived of intelligent cooperation, in 
fact of any kind of cooperation, and the land received no kind of 
care, which further changed the conditions. Our series of samples 
could not be made complete because of inopportune rains. This 
hindrance happened to me several times during the season. 
THE FIRST PLACE CHOSEN. 
The first place selected was a piece of land situated near the 
river and its drainage into the river was so free that the water 
backed up into the land when the water rose in the river and fell 
with it. This soil was sampled 20 Oct., 1911, to a depth of 60 inches, 
i. e. to the gravel which varies from 5 to 8p2 feet from the surface. 
The results are given in parts per million. 
ANALYSES OF SAMPLES FROM THE FIRST PLACE CHOSEN. 
1 to 6 inches 
7 to 12 inches 
13 to 22 inches 
23 to 32 inches 
33 to 42 inches 
43 to 49 inches 
50 to 60 inches 
Nitric Nitrogen Total Nitrogen 
109.0 931.6 
14.0 768.4 
11.0 510.0 
6.0 469.2 
2.6 530.0 
2.0 312.8 
2.0 346.8 
Another set of samples was collected 10 Dec., 1911. These 
samples are composite, each containing 22 subsamples. 
Nitric Nitrogen Total Nitrogen 
1 to 3 inches . 50.0 972.4 
4 to 6 inches . 26.0 884.0 
7 to 9 inches . 8.4 884.0 
Samples taken 15 April, 1912. Composite samples each con 
taining 22 subsamples. 
Nitric Nitrogen Total Nitrogen Chlorin 
1 to 3 inches . 64.0 850.0 4,304.7 
4 to 6 inches .•- 40.0 816.0 2,366.6 
Brown spot . 1,722.0 2,148.8 19,832.0 
Samples taken io July, 1912. 
1 to 3 inches . 486.9 1,196.8 12,344.0 
4 to 7 inches . 20. 748.0 1,443.0 
