CLOVER CROPS AND THE ^flXERALS IX THE SOIL. 207 



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. 



185-1. Clover. 

 Cunncrsdorf, Mausegast, Kotitz, Oberbobritzscli, Obcrschona. 



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 un- 

 equal 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 respect 

 of quantity and relative proportion, are very nearly the 

 same as for the potato plant (leaves, stalks, and tubers 

 included) : and if clover still pelds good crops upon a soil 

 wherein potatoes thrive but imperfectly, this is chiefly 

 owing to the wider root-ramification of the clover plant. 

 There are scarcely any two other plants which so clearly 

 indicate the layers of the soil assigned to them by nature, 

 for the absorption of their nutriment. 



If potatoes are planted in trenches two feet deep, and 



