23 
The Ammonifying Efficiency of Certain Coeorado Soils. 
manuring which was practiced on it, and containing a vigorous 
flora ammonifying bacteria/' The ammonia determinations with 
this soil were made after four days in place of seven as with the 
others. 
The Iowa sample carries the following description:—“The soil 
was typical of the Wisconsin Drift, being classed by the Bureau 
of Soils as Marshall loam. It was obtained from an experimental 
plot to which no lime had ever been applied—which, during the 
preceding five years had been continually in corn and which prior 
to that time had been in a general farming rotation.” 
With the exception of the New Jersey figures, the percentages 
given in Table No. 6 are based upon blood meal containing 13.05 
per cent, of total nitrogen, and cottonseed meal with 7.84 per cent, 
total nitrogen. In the New Jersey work, Lipman states that the 
blood meal and cottonseed meal used contained respectively 13.18 
per cent, and 6.405 per cent, total nitrogen. 
The California and Iowa samples fall considerably below the 
cultivated Colorado soils, containing nitrates, in ammonifying ef¬ 
ficiency, although the figures for the former may be low on ac¬ 
count of the four day experimental period in place of seven. New 
Jersey No. 1 appears to be greatly inferior to our soils, while No. 
2 compares very favorably. It is interesting to note, in passing 
how much more available linseed meal seems to be with the limed 
New Jersey soil than with ours. While the former gives 46.06 
per cent, nitrogen as ammonia, few Colorado soils will produce 
to exceed 13 per cent, and the majority less than 3 per cent. 
SUMMARY. 
The power to transform organic nitrogen into ammonia is a 
property common to many cultivated Colorado soils. 
Soils in the incipient stage of the niter trouble appear to sur¬ 
pass our normal soils in ammonifying efficiency. 
Compared with soils from other localities, our niter soils ex¬ 
cel in ammonifying efficiency to a very marked degree. 
Nineteen of the thirty-one soils examined have ammonified 
cottonseed meal more readily than the other nitrogenous materials 
employed; the remaining twelve have broken down the dried blood 
most easily; twenty-six have formed ammonia from alfalfa meal 
more readily than from flaxseed meal, and with five the reverse 
has been true. 
The maximum per cent, of ammonia produced in seven days 
by any soil from 100 m. g. of nitrogen as cottonseed meal was 
51.98%; as dried blood 2^.64%; as alfalfa meal 34.85%; 
as flaxseed meal 12.15%. / 
