CLOVER CHOPS AND THE MINERALS IN THE SOIL. 201 



which the oat plant derives its food : but they show the 

 state into which the arable surface soil had been brought 

 by the preceding corn crop. Owing to the abstraction 

 of phosphoric acid, and perhaps of nitrogen, the yield 

 of barley-corn was much less than might have been ex- 

 pected from the soil, judging by the preceding rye crop ; 

 and a small supply of superphosphate or guano would 

 have greatly increased the produce of barley on this 

 field. 



Clover, 1854. The clover crops in the fourth year 

 afford an insight into the condition of the deepest layers 

 from which plants draw their food. 



1854. CLOVER. 

 Cunnersdorf, Mausegast, Kotitz, Oberbobritzsch, Oberschona. 



The produce of clover at Cunnersdorf was nearly 

 twice as large as at Mausegast, and ten times greater 

 than at Oberbobritzsch ; and it is beyond doubt, that 

 these unequal crops must have corresponded to unequal 

 amounts in the soil of substances nutritive to the clover 

 plant. 



The substances required by the clover plant, in re- 

 spect of quantity and relative proportion, are very 

 nearly the same as for the potato plant (leaves, stalks, 



9* 



