146 HOW TO GROW GOOD CLOVER. 



will then take care of itself." But that the exportation of com may 

 possibly exercise an injurious influence on the cultivation of clover 

 or turnips ; that it is, above all, indispensable to restore to the soil the 

 mineral constituents of the coim, to enable the clover or turnip crop 

 to "take care of itself;" in other words, that in oi'der to grow clover, 

 turnip, &c, we must manure the land — this is a notion utterly 

 incomprehensible, nay absolutely impossible, for most agriculturists. 

 For, is not the clover grown for the sake of manure? What 

 advantage, then, would there be if it were necessary to manure 

 again to produce the clover 1 This clover the farmer expects to grow 

 for nothing. 



The mutual relations existing in the order of nature between the 

 two classes of plants are, however, as clear as daylight. The mineral 

 constituents of the clovei*, turnips, &c, and of the corn, form the con- 

 ditions for the production of the clover, turnips, &c, and of the corn, 

 and they are in their elements quite indentical. The clovers, &c, 

 require for their growth a certain amount of phosphoric acid, potash, 

 lime, magnesia, — so does the corn. The mineral constituents con- 

 tained in the clover are the same as those in the corn, plus a certain 

 excess of potash, lime, and sulphuric acid. The clover draws these 

 constituents from the soil ; the cereal plant receives them, — we may 

 so represent it from the clover. In selling his clover, therefore, the 

 farmer removes from his land the conditions for the production of 

 corn. If, on the other hand, he sells his corn, there will be no clover 

 crop in the following year ; for in his corn he has sold some of 

 the most essential conditions for the production of a clover crop. — 

 pp. 183-5. 



This discussion, then, upon the so-called clover- 

 sickness leads us to adopt the following propo- 

 sitions : — 



First. That the larger induced plant of our cultivated 

 clovers has not, as a rule, that perennial constitution 

 of the smaller wild species. 



Second. Even its induced habit is much dete- 

 riorated by transportation under adverse climatal 

 circumstances. 



