14 
COLORADO EXPERIMENT STATION 
in cultivation at one time, but which has been abandoned for the past 
two years, at least, for some unknown reason. The tract is situated 
well above the surrounding country on an imposing mesa, but in spite 
of its favorable location and elevation, it is a matter of common observa¬ 
tion that much of the land is too wet for successful farming without a 
great deal of draining. Why this condition should exist where every 
advantage appears to be offered for natural drainage has been some 
what of a quandary. During recent years, very extensive ditches 
and drains have been put through this section and incidentally we ob¬ 
served while the trenches were still open that the underlying shales 
present at their upper limit a series of basins, filled with coarse gravel, 
which appear to retain the irrigating waters and in this way interfere 
with natural drainage. 
The field in question was barren for the most part, although 
clumps of Russian thistles occurred here and there. The ground was 
wet in places from an over-flowing ditch and there was a very decided 
development of large brown areas. Everything indicated that these 
were niter spots. Accordingly, I took a composite sample of the 
brown surface-inch from a number of dark brown patches on the 
ridge of what looked to be an old sugar-beet row. 
The soil is a clay and the surface color varied from a yellowish 
brown to chocolate. A determination of the nitric nitrogen showed it 
to contain 1360 p. p. m. with 32,400 p. p. m. of chlorin. 
Sample No. 82 .—This sample was taken exactly six feet from the 
brown area described in No. 81 and consisted of the second to fifth 
inches. The soil was very dry and rather mealy on the surface, but 
there was no indication whatever of any brown color. Russian thistles 
had grown on this particular spot luxuriantly and had to be removed 
before securing the sample. This soil, from just beyond the limits of rhe 
brown areas, together with No. 81 from the brown crust gave me an 
excellent opportunity to compare the microbic activities under two such 
different soil conditions where the two samples occurred less than seven 
feet from one another. The soil contained 46 p. p. m, of nitric nitrogen 
as compared with 1,360 in the brown crust. The chlorin present 
amounted to 9.800 p. p. m. 
Sample No. 83 .—This soil came from, an orchard in prime bearing 
condition where seven trees had been killed by niter in 1911. These 
trees were all in one row, although not adjacent. They were cut down 
in the fall of 1911 and when I visited the orchard in September, 1912, 
the water sprouts from these stumps showed very severe nitre burning. 
My sample was taken between two of the stumps and consisted of the 
surface-three inches. The soil is a very heavy clay. No new cases of 
burning had been observed in the orchard that summer and there was 
no indication of the trouble spreading to adjacent rows. Seven of the 
trees in another row bore rather scant foliage and small fruit but this 
condition might have been due to a variety of causes. This soil contain¬ 
ed 6 p. p. m. of nitric nitrogen and 58 p. p. m. of chlorin. I should con¬ 
sider this orchard in the incipient stage of the trouble. 
