Rotation of Crops 



every kind of crop. The plants must be some 

 distance apart or they would be trodden under 

 foot, cut off or uprooted by the implement 

 used. We cannot think of weeding wheat, 

 because the blades are too close to each other ; 

 but potatoes, which are far apart, can be 

 weeded without difficulty. By the weeding 

 all useless and noxious plants are destroyed 

 and their return is prevented by pulling them 

 up before the seed ripens. The ground is 

 perfectly cleared and prepared to receive a 

 more delicate crop. This shows the ad- 

 vantage of anticipating the cultivation of 

 cereals by that of the potato, or of any other 

 plant that can be weeded. 



The second year will mark the arrival of 

 the wheat. Having been cleansed by the 

 former crop the earth produces no weeds. It 

 needs no more manure ; for although the 

 tubers of the potato have removed certain 

 substances, these substances are not the same 

 as those required by the wheat ; and, more- 

 over, the heads which have been buried and 

 converted to humus will compensate for that 

 which the tubers have taken from the ground 

 by the matter which they have absorbed from 

 the air. So the wheat has come at the right 

 time. 



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