The Survival in Farming. 
259 
prices, the limit is below tlie standard of expenditure recognised 
as constituting high forming. If we obtain an increase of 50 
per cent, in a crop through putting on the land a certain 
quantity of manure, it is likely that the use of double the 
quantity of manure will give a further increase of ifo more than 
25 per cent. In this illustration of the law of diminishing 
returns it is obvious that the percentage of profit is less on the 
heavier dressing than on the light one, and yet it may be more 
than sufficient to cover the extra expenditure. But, if Ave treble 
the quantity of manure, the chances are that the produce in 
excess of that obtained from the double dressing will not be 
great enough to repay the cost of the extra manure. Indeed, 
it often happens that a very heavy dressing does more harm 
than good. 
A few years ago Sir John Lawes published an article in 
which he expressed the opinion that such high farming as was 
illustrated on some of his experimental plots at Rothamsted was 
not remunerative at the current prices of corn. That statement 
was quite true, except that such farming as was referred to ought 
to have been termed extravagant rather than merely high. The 
greatest average yield of wheat during thirty-eight years ending 
with 1889, at Rothamsted, was 36^ bushels an acre, obtained by 
the annual use of 600 lb. of ammonia salts, 3^ cwt. of super- 
phosphate, 200 lb. of sulphate of potash, and 100 lb. each of 
sulphates of soda and magnesia. No high farmer of experience 
would dream of using such quantities of manure for a wheat crop, 
although the application is valuable for jjurposes of experiment. 
To parody a well-known saying, it is magnificent ; but it is not 
farming. 
The average yield for the same period on a plot to which 
two-thirds of the quantity of ammonia salts named above 
were applied yearly, with the same quantities of the other 
manures, was only 3| bushels an acre less than the maximum, 
and the extra yield did not pay for the extra manure. But this 
medium dressing of ammonia salts, with the other manures, 
gave an average yield of 8| bushels more than was obtained 
from the use of 200 lb. of ammonia salts, with the same 
quantities of other manures ; and the application of the extra 
200 lb. was profitable even at recent low prices. It is to be 
borne in mind, too, that the smallest of the three dressings 
would be a liberal one under an ordinary system of rotation, 
though not on land continuously cropped with wheat. Under 
the ordinary rotation, again, the potash, soda, and magnesia, for 
most soils, might be dispensed with. Even if we take into 
consideration such high farming as is illustrated on the plot to 
