246 THE LIVING ORGANISMS OF THE SOIL [chap. vn. 



substituting, for example, mangolds for turnips in the 

 next rotation ; every effort should be made to destroy 

 cruciferous weeds like charlock ; turnip-fed dung should 

 not be applied, and another dressing of finely divided 

 quicklime should be put on for the crop preceding 

 the sowing of the new turnip crop. 



