Fixation ot Nitrogen in Colorado Soils 
39 
ooiiditioiis. Tliere is no question but that a still larger portion 
will be abandoned in the sprang of 1921, for some of this land 
^ whicli was cultivated last spring, 1920, is at this time entirely 
devoid of any vegetation. This affected area is on the side of a 
: low hill and is rapidly extending up the hill. This ground is 
. wet, seeped, but where this water comes from is not evident, 
and the question becomes more perplexing the longer we ob- 
; serve it. There is no apparent source from which this water 
\ may come. It is an easy matter to suggest irrigation and leak- 
' age from irrigating ditches, (there are two of these perhaps a 
mile to the east of this place) as the cause of this excessive 
moisture. This would seem plausible, but the more familiar one 
; becomes with the facts in this section, considering at the same 
i time the contour of the land, the more uncertain one becomes 
in regard to the validity of such an explanation. The water 
can scarcely come from any depth, for on the crest of this low 
hill — perhaps 200 feet from the western margin of this nitre- 
i area — there is a deep well, 400 feet to water, which carries 4T70 
p.p.m. total solids but no nitric nitrogen. Whereas, the worst 
I portion of this area carries nitric nitrogen equivalent to sodic 
nitrate equal to 2.5 percent or rather more of the air-dried soil. 
Some of the land at the foot of this hill and west of the road is 
drained, but its condition is very bad. 
FIXATION IN A NITRE AREA 
In order to ascertain how vigorous a fixation the afore- 
i mentioned area might manifest, five samples were taken and 
^ incubated for 30 days at 27°C. Twelve hundred ^rams of air- 
1 dried soil were taken and enough ammonia-free distiRed water 
1 added to bring the moisture content up to about 15.0 percent. 
The five samples represent,a section from north to south across 
1 the shorter diameter of the area. Sample 1, apparently normal 
i soil, was taken in the field 60 feet north of the area; sample 2 
was taken 30 feet north of what we considered the northern 
I margin of the area; sample 3 at the northern margin of the 
area; sample 4 at the southern margin, and sample 5 stiU 
I further south in an alfalfa field on the flank of a portion of 
' this same hill. 
Before 
Ineiibatioii 
After 
30 Days 
After 40 
Days 
Sample Total 
Nitric 
Total 
Nitric 
Total 
Nitric 
Nitrogen 
Nitrogen 
Nitrogen 
Nitrogen 
Nitrogen 
Nitrogen 
1 
0.1054 
0.00175 
0.1163 
0.00458 
0.1045 
0.00459 
2 
0.1018 
0.00197 
0.1031 
0.00432 
0.1029 
0.00420 
3 
0.2570 
0.13615 
0.2574 
0.1477 
0.2590 
0.1402 
4 
0.3395 
0.2068 
0.3620 
0.2261 
0.3620 
0.2023 
5 
0.1315 
0.0034 
0.1282 
0.0070 
0.1284 
0.0135 
The worst 
portion of this 
area is not 
included in 
these samples. 
It was 
i very rich in nitric nitrogen, carrying 4,500 p. p. m. 
