14 
IMPERIAL COLLEGE OF 
The maximum quantity of nitrogen furnished to the plats 
in series A is only half the quantity required by a normal crop ; 
but in series B it is present in the amount required by the 
plant. The potash and phosphoric acid are supplied in series 
A according to the demands of a normal crop and in series B 
they are present in twice the necessary quantity. These 
proportions were adopted with a view to make the influence of 
the nitrogen more conspicuous by comparison. The results 
on this point are, however, not as satisfactory as could 
have been desired. In the majority of cases the nitrogen 
does not seem to materially increase the yield. The chief 
exception to this occurs in plat 19. On plat 17, 905 grams 
superphosphate produced a yield of 7.95 kilograms grain ; while 
on plat 19 the same amount of superphosphate and an addition 
of 1,360 grams nitrate raised the yield to 9.22 kilograms 
grain. But in view of the uniformly slight increase in yield 
on the other plats to which nitrate was added, in some cases 
even apparently lowering the yield, the result in No. 19 should 
be regarded with suspicion, as it is probably owing to inequality 
in the soil. Even on plat 24 where there are the same amounts 
of superphosphate and nitrate, plus 455 grams sulphate of 
ammonium the yield is considerably less than on plat 19, and 
more in keeping with the results of nitrogen on the other 
plats. But perhaps the fairest estimate of its effects can be 
had from the results on plats 9 and 21, which were furnished 
with nitrate of sodium only. Plat 9 had a half dose, 182 lbs. 
pr. acre, and plat 21 had a full dose of 364 lbs. pr. acre. The 
yield on the unmanured plat in series A, (No. 7), was 6.14 
kilograms grain ; on plat 9 it was 6.85 kilogi'ams a difference 
of 710 grams in favor of the nitrate, an increase equal to about 
3.8 bushels pr. acre. Comparing the unmanured plat (18) with 
plat 21 in series B, we find the difference to be but 430 grams 
although the quantity of nitrate was doubled. The average of 
the two unmanured plats is 6.55 kilog.; the average of the two 
nitrate plats is 7.12, an increase of 570 grams in favor of the 
latter. If this may be taken to represent the normal increase 
in the yield of upland rice from an application of nitrate of 
