MANURING OF POTATOES. AAI 

which was quite independent of the others, was so striking, 
and the number of farms on which the experiments were 
conducted was so great, as to exclude any probability of error. 
The differences revealed in these several experiments in the 
capacity of varieties of potatoes to respond to the application 
of manures constitute a discovery of exceptional practical 
Liffect of Manures on the Up-to-Date v. Muincrop Potato. 

_| Increase per acre | Increase per acre 
Plot Manures applied produced by produced by 
; per acre. Manures on the Manures on the 
Maincrop Potato. | Up-to-Date Potato. 


Tons. Cw. Tons. Cz. 
leNe 20 tons farmyard manure | 3 4 4 18 
| 
| 
B. Io tons farmyard manure, | 
with about 6% cwt. | 
artificials - = 3 We 5 85 
(Ce 11 cwt. artificial manure | 
| 2? 1 
only - - - >| 2 I 5 2 



‘importance. This becomes very evident when it is considered 
that the difference in value of the increased produce of the 
Up-to-Date over that of the Maincrop potato in the Giasgow 
experiments was equal to, or greater than, the whole cost of 
the manures applied. The obvious inference is that the 
whole question of the economy of applying particular manures 
to the potato crop must depend very largely on the selection 
for cultivation of the varieties that possess the greatest 
capacity for responding to the treatment accorded to them, 
and that manures which will give a very profitable return 
when applied to one kind of potato may not do so when 
applied to another. 
A curious and suggestive feature in these results was the 
small difference in cropping capacity shown by the Up-to- 
Date and Maincrop potatoes on unmanured land as com- 
pared with that shown when manures were applied. On the 
unmanured land the yield of the Up-to-Date exceeded that 
of the Maincrop by only 104 cwt., while on the fully manured 
land the difference in yield amounted to nearly 2 tons per 
