The Root 



ground, enriched by this manure, has pro- 

 duced a first harvest of wheat. But the 

 wheat, with its short delicate roots, has only 

 benefited by the fertilising qualities of the 

 superficial layer, and has left those untouched 

 which have been dissolved by the rain and 

 transported to a lower depth. It is true that 

 the plant has fulfilled its duty admirably ; it 

 has made a clean sweep and converted into 

 wheat all the manure contained by the soil 

 within reach of its roots, so that if wheat were 

 sown again there would be no harvest. The 

 ground is exhausted on the surface, but there 

 is still wealth below. Is there anything that 

 can search the layers underneath and extract 

 food from them ? It will be neither barley, 

 oats, nor rye, the small fasciculated roots of 

 which would find that the wheat had left 

 them nothing in the top story of the ground. 

 It will be lucerne, which will plunge its roots, 

 as thick as a finger, to a depth of one, two, 

 or three yards, bringing back the manure as 

 forage which, with the help of the animal 

 that feeds on it, will turn to flesh for food, 

 milk, fleece, or at any rate, labour. This 

 succession of two or three plants, deriving 

 the greatest advantage from prepared ground, 

 is called rotation. 



55 



