27 
The veiy concordant results in the above table add proof to the 
theory that the fixation of ammonium nitrogen and potash are 
strikingly similar. The fixing power of the soils was far less for 
the nitrogen of ammonium sulphate in mixtures than when used 
alone. It was found that the heat decreased the fixing power of the 
soil greatly, while chloroform had a very slight effect. 
All solutions used in this series contained 172 parts per million 
nitrogen from ammonium sulphate. 
SODIUM NITRATE. 
The following table gives the results of applying sodium nitrate in 
mixtures : 
Absorption of nitrogen from a solution of sodium nitrate in a mixtd fertilizer . 
[Expressed in parts per million nitrogen in the percolate.] 
Soil No. 517. Soil No. 428. 
Percolates of 100 cc. each. 
Sodium nitrate, calcium phos- 
phate, and potassium sul- 
phate. 
Sodium nitrate, calcium phos- 
phate, and potassium sul- 
phate. 
Un- 
treated. 
Heated. 
Chloro- 
form. 
Un- 
treated. 
Heated. 
Chloro- 
form. 
100 
225 
210 
210 
165 
215 
220 
210 
215 
210 
215 
245 
200 
200 
170 
215 
190 
160 
175 
190 
215 
190 
215 
220 
225 
215 
185 
200 
no 
300 
145 
500 
220 
700 
215 
SUMMARY. 
Nitrogen added to 100 grams soil. . .gram. 
Nitrogen fixed by 100 grams soil do. . . 
Per cent of nitrogen fixed 
0. 1075 
0.1075 
0.1075 
0.1075 
0. 1075 
.0060 
.0010 
.0085 
.0145 
.0010 
5.6 
0.9 
7.9 
13.5 
0.9 
0. 1075 
.0200 
18.6 
The solutions used contained 215 parts per million nitrogen from 
nitrates, and, as was to be expected, the soils absorbed only extremely 
small amounts. The fixing power was shown to be very much less 
when this salt was applied in mixtures than when applied alone, 
the effect of heat was to decrease the fixing power, while the effect 
of chloroform was to produce a decided increase in fixing power. 
The latter is probably due to the sterilizing effect of the antiseptic 
upon the organisms present. 
REMOVAL OF ABSORBED SALTS. 
At the conclusion of the preceding series distilled water was 
allowed to percolate through the tubes at the rate of 100 cubic centi- 
meters in 24 hours. In eveiy 100 cubic centimeters of the solution 
after the first thus obtained phosphoric acid, potash, and nitrogen 
were determined. 
