The Ammonifying Efficiency of Certain Colorado Soils. 15 
Sample No. 20. 
Our next case presents a very interesting history. In i9o8 the 
field was planted to oats but it was only a short time until a num¬ 
ber of brown, mealy patches, on which nothing would grow, de¬ 
veloped on the higher places. It should be mentioned in passing 
that seepage had given some trouble in former years, and for that 
reason the growing of alfalfa on that piece of ground had been 
abandoned. In 1909 the land was planted to sugai beets, but the 
stand was very poor; there were great barren areas of half an acre 
in extent where nothing would grow. These bare spots were de¬ 
cidedly brown and mealy. The beet crop was almost a total failure, 
and that fall the field was seeded to winter wheat. The spring of 
1910 brought no relief, for the whole twenty-five acres of wheat 
perished long before harvest. The greater part of the tract re¬ 
mained a barren waste all that summer,, with not even a Russian 
thistle growing on it. As has been mentioned before, the pi ecipita- 
tion for the winter and spring of 1910 and 1911 was unusually 
heavy and prolonged, and whether it was due to the leaching re¬ 
sulting from this, or to some other unknown cause, I know not, but 
in 1911 the whole area blossomed out in a most luxuriant growth 
of saltbush and Russian thistles chest high. So far as our present 
observations go, this field and No. 6 are the only instances where 
niter areas have shown any tendency toward recovery. The sur¬ 
face of the soil was moist and green with a moss protonema when 
I took my sample in October, 1911- It is 4 clay loam and mealy 
in spots beneath the brown crust. The results of the amnapnifRation 
experiment are as follows: 
From cottonseed meal, 48.23% nitrogen was recovered as am¬ 
monia in seven days; dried blood 38.98%; alfalfa meal 9.81%; 
flaxseed meal 5.07%. 
Sample No. 21. 
Sample No. 21 was taken in the fall of 1911 from an orchard 
where the niter injury was first observed in 1909. During 19091 
and 1910 approximately two and a half acres had been killed, and 
the remainder of the trees were unquestionably affected in 191.1 
but the progress of the trouble seemd to have been retarded from 
some cause. In place of the trees being entirely destroyed iir a 
month to six weeks, as is frequent v true, these dragged along, half 
leaved out and sickly looking, throughout the season. I am unable 
to say whether they came out in leaf this spring or not. I obtained 
a sample of this soil in 1910 and found it to possess marked nitrogen 
fixing powers. In thirty days it gave an increase of 9.807 m. g. of nitro¬ 
gen per 100 c. c. of mannlte solution. The soil is a clay loam and shows 
the brown stain of the Azotobacter pigment readily. The ammoni- 
fication test made from soil'secured in October, 1911, gave the fol¬ 
lowing: 
From cottonseed meal 47.87% nitrogen recovered as ammonia : 
dried Rood 49.16%; alfalfa meal 12.22% ; flaxseed meal .77%. 
