20 The Colorado Experiment Station 
made but on the other occasions we took only six sections. We did 
not use an auger in taking these samples, but opened a trench, pre¬ 
pared a clean vertical face, and took the samples from this. In order 
to exhibit still more fully the conditions in this ground, samples of 
surface-soil were taken from open spots in an adjoining alfalfa 
field similar in location and character to this land chosen for sys¬ 
tematic sampling, and also samples of “brown spots” which oc¬ 
curred within this area. There were no “brown spots” in the al¬ 
falfa field. In addition to these soil samples, we also took three 
samples of ground-water obtained from the trenches dug for making 
the vertical sections. The acre of land chosen was located so that 
it gave us a variety of conditions and also included distinct cases 
of “brown spots.” The samples from the open spots in the alfalfa 
field were taken because this land is as unfavorably situated as that 
chosen and is the continuation of it westward. This land, except for 
these spots, is occupied by a fairly good stand of alfalfa. To re¬ 
state the matter of sampling: We have systematically taken com¬ 
posite samples each representing one-sixth of an acre. We have 
three series of vertical sections consisting of six members each, 
samples from “brown spots,” surface-soil outside of the “brown 
spots,” surface-soil from similar adjoining land, and samples of 
ground-water. I regret that this work could not have been done in 
1910 and 1911 for the conditions were far less intense in 1912 and 
the land received much better care in these years than in 1912. The 
results are again given in parts per million. Each of the following 
sample, representing one-sixth of an acre, is a composite one con¬ 
taining 60 subsamples. The numbers 1, 2, 3, 4, 5 and 6 represent 
the same order of sections. 
When I went in August to take my samples, I found this land 
so occupied by weeds, wild lettuce, Russian thistle, etc., that I con¬ 
sidered it impossible to obtain satisfactory results and the sampling 
was given up and there are no general systematic samples.subse¬ 
quent to this date. 
ANALYSES OF SAMPLES FROM THE THIRD PLACE CHOSEN. 
Samples taken April 15, 1912. 
Nitric Nitrogen 
Total Nitrogen 
Chlorin 
1. 1 to 3 inches . 
1,115.2 
2,696.9 
2. 1 to 3 inches . 
. 387.5 
1,142.4 
1,139.7 
3. 1 to 3 inches . 
. 367.0 
1,074.4 
1,542.0 
4. 1 to 3 inches . 
. 70.0 
816.0 
412.3 
5. 1 to 3 inches . 
625.6 
66.0 
6. 1 to 3 inches . 
. 4.0 
639.2 
156.7 
Alfalfa field . 
1,353.2 
7,693.4 
“Brown spot,” southwest corner. 
. 1,803.0 
1,897.2 
18,884.0 
Brown top soil . 
. 10,000.5 
14,920.0 
14,464.0 
