Nitrogen Fixation 41 
qualitatively for nitric acid and find it present in quantities, which 
are easily detected. I have been kindly furnished with samples of 
Steffens waste water from several factories in this state and find 
them uniformly rich enough in nitrates to give a strong reaction 
without one’s going to any particular trouble to prepare the waste 
water. There is nothing new in the occurrence of nitric acid or 
nitrates in beets. It has been shown that the leaves have contained 
as much as 0.16 per cent of their green weight, which is stated to 
be exceptional in plants. Stock beets have been found to contain 
0.126 per cent and sugar beets 0.164 per cent of their green weight. 
The last percentage was found in beets which had been heavily 
manured with saltpetre or other highly nitrogenous manures. No 
information is given concerning their deportment in the factory. 
The nitrates have been considered as exercising a prejudicial in¬ 
fluence on the working qualities of the beets if applied alone, in con¬ 
siderable quantities and after the plant has attained to some size. 
It seems possible that we may have in these facts the explanation 
for the deterioration of our beets. The nitrates are being con¬ 
tinuously formed in our soils. In the turn row of field fifteen, we 
find nitric acid equivalent to 1,680 pounds of sodic nitrate in the 
surface six inches per acre whereas we find the equivalent of only 
120 pounds in the furrow between the rows. We must be careful 
about drawing extreme conclusions in regard to the amount of ni¬ 
trates used by the crop. The quantity was almost certainly materi¬ 
ally less than the difference between 1,680 and 120 pounds because 
the ground had been shaded by the beets during most of the season 
and this would make some difference; further, the row had been 
washed out by the irrigation water applied, etc., but the possible 
supply for the beets grown on this field was as much as 1,680 
pounds in the top six inches of soil per acre. This determination 
was repeated and checked by the determination of the nitric acid 
in the aqueous extract of the soil by a different method. 
The soils here considered are such as were planted to beets last 
season, 1909. The extreme cases given in other portions of this 
bulletin are soils in which this process of fixation has proceeded so 
far that they are now barren, due to the excessive amounts of 
nitrates. 
The past season may have been an exceptionally favorable one 
for the azotobacter and we may not have the recurrence of such 
serious results for years; there is, however, no assurance that this 
may be the case. In fact we have no data relative to the effects of 
the season upon the activity of the bacteria. 
One question has undoubtedly suggested itself in regard to the 
origin of these nitrates, i. e., whether the popular idea that the irri¬ 
gation water brings them to the surface may not be correct. Some 
