ENGLISH AGRICULTURE. 199 



not to be grown on the same land more frequently than once 

 in twenty years. 



Upon rich alluvial soils, the heavier loams, and the soils of 

 the old and new red sandstones, potatoes often occupy an 

 important position in a rotation of crops. Thus near Dundee, 

 on the rich soils of the old red sandstone, a rotation is 

 practised known as the East Lothian system, consisting of 

 a six years' course arranged as follows : 



1st year. Turnips and swedes. 



2nd Barley (half dunged). 



3rd Clover. 



4th Oats (top dressed). 



5th Potatoes. 



6th Wheat. 



Potatoes, although in a sense a fallowing crop, or a crop 

 which insures land being highly manured, clean, and well 

 worked, is still an exhausting crop, because it is sold off the 

 farm. In the above rotation they occupy a position not dis- 

 similar from that of beans in the Holderness rotation, but 

 take the place of a corn crop rather than of a fodder crop. 

 The objection to potatoes superseding the genuine root crops 

 is that every acre devoted to potatoes directly infringes upon 

 the area set aside for live stock, and if cultivated in this 

 position, on an extensive scale, would cause a necessary 

 diminution in the number of sheep and cattle maintained. 



