144 HOW TO GROW GOOD CLOVE B. 



out of humus or peaty vegetable matter and the 

 destruction of insects had their share in the induced 

 change. 



Still, however much we may suppose that the 

 failure of the clover crop is influenced by the alteration 

 of its constitution as the result of cultivation, the 

 presence of choking weeds, or by the presence of 

 prejudicial ingredients, especially in thin soils, there 

 can be no doubt that the principal cause of the diffi- 

 culty will be found in the fact that the corn crop with 

 which the clover is grown exhausts the soil, in the 

 most unsparing manner, of the very chemical ingre- 

 dients which the clover requires. 



Thus, if sheep are folded on a crop of turnips, the 

 whole of this crop is converted into a manure at once 

 available for the grain crop, by which it is quickly 

 appropriated and then taken away. Here, then, we 

 may suppose at starting that the clover is half starved ; 

 and, with a constitution drawn up in the effort of the 

 plants to obtain a glance of sunshine, and weakened 

 for the want of nourishment, it is expected to bear 

 our inclement winters. 



This argument will be made all the clearer if we 

 place side by side the result of the analyses of barley 

 and clovers, and especially if we consider what a 

 quantity of mineral matter is taken in a short time, 

 and by a crop ripening its straw and seed. 



Now, if we look at these figures we shall see how 

 much of the mineral matter required for the clover 

 has been previously abstracted by the barley, and if 

 at the same time we reflect that this robbery may, 

 and too often does, co-exist with the other causes 

 which we have instanced as tending to clover-sickness, 



