90 CONTINUOUS CROPPING 



sprayed and sprouted. There are times when on 

 hearing this type of criticism advanced, one ahnost 

 despairs of agriculture. A man advancing such a 

 criticism knows as much about the principles under- 

 lying agricultural practice or science as a billy goat 

 does of the science of eugenics. 



If on two plots of land receiving the same amount 

 of manure one plot gives a yield of 5 tons of potatoes to 

 the statute acre, and double the yield is obtained from 

 the second plot through the adoption of a better system 

 of potato growing, such as sprouting and spraying, 

 it is only reasonable to expect that the plot giving the 

 double yield has taken more out of the land than the 

 low-yielding crop. But 5 or 6 tons of an extra yield 

 of potatoes would surely put a man in a position to 

 buy a little extra manure to restore the balance of the 

 fertility which had been taken from the land by the 

 extra yield. 



DETAILS OF SPRAYING 



There are two spraying mixtures generally recom- 

 mended for potatoes, the Bordeaux mixture and the 

 Burgundy mixture. 



The former mixture is made in the following pro- 

 portions : 2 lb. of sulphate of copper (commonly called 

 bluestone) and i lb. of unslaked lime to every 10 gallons 

 of water. The Burgundy mixture consists of 2 lb. of 

 sulphate of copper and 2 J lb. of washing-soda to every 

 10 gallons of water. 



Personally I much prefer the Burgundy mixture ; 

 it sticks on the leaves far better than the other, it is 

 much easier to prepare, and the nozzles of the spraying 

 machine are not so likely to become clogged by its 

 use. 



