104 J. K. TAYLOR. 
, 
Once again we are faced with arise in January in all 
cases, but the table has a number of anomalies, é€.g. the 
small figures for February and March with “‘ Lucerne”’ soil 
are not correlated with the increase of nitrates (see Table 
IV). But if we accept this table as correct we are faced 
with the difficulty of saying why four plots side by side, 
two fallowed, two cropped, should in every case show a 
difference in nitrifying power sometimes very considerable. 
The writer believes the table sufficiently accurate to justify 
a complete experimental enquiry into the correctness of 
this hypothesis and as to the reason for the changes. 
It was thought at times that different amounts of 
ammonium sulphate might alter these conclusions or might 
be more completely nitrified. In consequence 25, 50 and 
100 mgs. respectively of the salt were added to the soil in 
the experiment and in another series °2 grm. of dried blood 
were used, the incubation being four weeks with optimum 
water content at optimum temperature. The result is 
shown for two soils PB and PC in Table VIII. 
Table VIII.—Percentage Nitrification of (NH,),SO, (using 
different concentrations) and of Dried Blood. 






4 A PB EXO) 
Amount ot | 
(NH,4)28S0, | December, March |December| March 
added. sample. | sainple. | sample. | sample. 
~ iy of, fo of of 
25 mgs. 71:6 64:0 52°8 67°6 
50 mgs. 48-0 0) 33-0 435°) 
100 mgs. 26°4 17:0 12°3 24°5 
a'2¢m. dried 25:7 98-9 Bey 50) 39-6 
**blood 






It is apparent that using the smallest amount of ammon- 
ium sulphate, the highest percentage of nitrification was 
obtained, but in no case was there a greater quantity of 
nitrate produced than with the 50 ng. additions. In the 


