172 BOTANICAL GAZETTE [MARCH 
anions. This indicates a very marked acceleration of the speed 
with which the protein is transferred into ammonia, which would 
result in a greater available supply of this compound for the action 
of the nitrifiers. The speed with which the ammonia is oxidized to 
nitric acid also increases with the addition of various salts, as is 
brought out in table VIII. 
TABLE VIII 
PERCENTAGES OF NITRIC NITROGEN PRODUCED IN SOIL TO WHICH VARIOUS SALTS WERE 
ADDED, THE UNTREATED SOIL BEING TAKEN AS I00 PER CENT 
Chloride Nitrate Sulphate Carbonate 
SO ete eens 142.0 IOI.o 100.0 100.0 
Potmssnt oe 106.5 106.4 100 100.0 
Cale 34 625 Sha ts Ns 00. 102.1 196.7 100.0 
Mapnesium 2. 123.2 106.5 TOI.2 140.7 
etic es ee ius 112.9 125.4 113.2 108.4 
Pe he nap rn rie aan 128.4 100.0 I02.0 117.4 
TABLE IX 
PERCENTAGES OF NITROGEN FIXED IN SOIL TO WHICH VARIOUS SALTS WERE ADDED, 
THE UNTREATED SOIL BEING TAKEN AS I00 PER CENT 
Chloride Nitrate Sulphate Carbonate Average 
PUM... eee eece ee: 102.6 102.7 104.4 To7.3 104.2 
Potosi. 3. ise; 100.0 101.3 105.0 100.0 101.6 
CUM. ......-.0560- 167.6 109.9 « 102.6 103.3 104.0 
Magnestim: 2.050200. 55 102.2 IO1.9 101.7 IOI.9 I0I.9 
Manganese. . 5. 2000.45. 102.3 102.2 102.4 100. IOI.7 
MON oe eee eects cis 104.3 102.0 100.4 101.8 102.1 
PVOTRRE. kre. IOr.9 103.3 10207 502.5. Fis 
All but six of these salts increase the accumulation of nitrates 
in the soil. Two which did not stimulate the ammonifiers also 
failed to stimulate the nitrifiers. In four cases there was no 
agreement between ammonifiers and nitrifiers. The manganese 
and iron salts are both strong stimulants, as was the case with the 
nitrifiers; potassium, which is an essential element, is the least 
effective of the cations, whereas chlorine is one of the most active, 
being exceeded in activity only by the sulphate ion. 
It is evident that the nitrogen available to higher plants would 
be very materially increased through the addition of salts to a soil, 
