212 AGRICULTURE 



In parts of the country where the potato 

 crop is of special importance, a rotation is 

 selected which will permit of a large pro- 

 portion of the farm being put under this 

 crop. If the farmer is satisfied with one-fifth 

 of his total tillage area under potatoes, he 

 can select the Norfolk four-course shift and 

 introduce potatoes between seeds and wheat, 

 thereby converting a four-course into a 

 five-course rotation. Potatoes are found to 

 grow well after a one-year's ley, but if one- 

 fifth of the farm is not considered sufficient 

 for the potato crop, part or all of the " break " 

 that would, under ordinary circumstances, 

 be devoted to turnips or mangolds can also 

 be placed under potatoes. If all the root 

 break were given over to potatoes, it would 

 mean that a farm worked upon such a five- 

 course rotation would show two-fifths of 

 the whole under this crop. 



It is in districts where the climate, soil, 

 and system of farming encourage the cultiva- 

 tion of catch-crops that the planning of a 

 rotation requires most attention. On the 

 extensive tracts of Down land in the south 

 and east of England, where sheep-breeding 

 is the mainstay of farming, the system of 

 cropping is primarily arranged to provide 

 a continuous supply of suitable green food 



