12 
Colorado Experiment Station. 
little or no fixation could be accomplished ; that the fourteenth inch sam¬ 
ple, while rich in nitrates, did not carry enough to inhibit entirely the 
growth of the nitrogen fixing bacteria, and that in No. 4, the condi¬ 
tions were very favorable for these organisms. 
Sample No. 5. 
This sample was procured September 21, 1909, from an orchard 
between the irrigating furrows. The brown surface soil, a light clay 
loam, was removed and a section, including the second to sixth inch, 
was taken. In 1908 a few of the trees had died and the owner, be¬ 
lieving that possibly this had been caused by lack of fertility, had given 
the orchard a liberal dressing of stable manure. The following spring 
the ground from which the dead trees had been removed, one to two 
acres perhaps, along with seven or eight acres of the orchard, was sown 
to wheat, but to the dismay of all concerned this, too, failed to grow, 
only a very small percent ever coming up. During the summer, 1909, 
fifteen to twenty-year-old trees died by the score, beginning early in 
the season and continuing late into the fall. A conservative figure 
for the damage done this year would be the loss of 300 bearing apple 
trees. 
1910 saw a continued spread of the burning, and already in 1911 
the attack is being renewed with increased vigor. 
In the culture solution, the growth took the form of a dull, almost 
continuous scum, with patches of white, gelatinous material here and 
there. There was a slight acid production with the odor of butyric 
ether at times. The microbic flora consisted principally of large rods, 
mycelial threads and many clostridium forms resembling closely, if 
not identical with, Clostridium pastorianum. An increase of 3.0822 m. 
g. of nitrogen was obtained in thirty days. 
Sample No. 6. 
The material for this test was taken from the top of a brown irri¬ 
gating furrow in a beet field. The surface crust was removed and the 
next four inches used. The soil was a sandy clay and the field was in 
alfalfa in 1906. At this time complaints were received of the appearance 
of bare spots on which the alfalfa was dying out. The largest of these 
was horse-shoe shaped and about one-half acre in extent. The chief 
trouble in this instance was seepage but in 1908 the field was sown to 
oats, and it was not long before a number of brown patches, mealy in 
character, developed on the higher places. When the land was being 
prepared for beets in 1909, there was nothing unusual to create one’s 
suspicion except the seepage. I visited the field in September and 
there were great bare spots surrounded by beets with immense tops. 
This is shown in Fig. 2, page 13. The stand had evidently been 
very poor since some of the barren places would average a half acre 
in area. The soil was mealy and high in nitric acid. That fall the 
land was sown to winter wheat and when I saw it the next summer, 
the whole twenty-five acres was a total failure. 
