ENGLISH AGRICULTURE. 165 



liko the use of these expressions, which savour of allegory, 

 and are therefore probably misleading. The real fact is, 

 that certain special manures develop or bring out the 

 powers of the ground. By allowing a crop plenty of nitrogen 

 we enable it to seize upon a larger proportion of mineral 

 matters. By adding to a soil any constituent in which it is 

 deficient plants are enabled to develop thoroughly, and to take 

 up the remaining materials which are present in abundance 

 in the soil. This I think must be evident from the law of 

 minimum which was first enunciated by Liebig. If a plant 

 cannot get all the necessary constituents it remains puny in 

 growth, but if we supply the missing link the vigour of the 

 plant is restored. There is no doubt, that when a soil is 

 thoroughly stocked with available mineral matter, by supply- 

 ing nitrogenous matter the plant thrives amain ; it can then 

 easily obtain every constituent which it requires from the 

 ground, and thus the use of the special manure consists in 

 enabling the plant to realize the latent wealth of the soil. 

 This is the way I should prefer to [explain the fact before us, 

 rather than by using allegorical phrases. 



I shall now give a few illustrations showing the preponder- 

 ating importance of phosphatic and nitrogenous fertilizers. 

 It would scarcely do to dismiss the whole subject of fertilizers 

 by merely stating that it is only necessary to put plenty of 

 phosphates and plenty of nitrogen in the soil. That would 

 be reducing an important study to a very trite conclusion. 

 Nevertheless, the farmer who keeps steadily in view that he 

 must give his corn crops nitrates and his turnip crop phos- 

 phates will not get very far wrong. But in examining the 

 composition of plants, and in glancing at their requirements, 

 we find a number of other substances besides nitrogen and 

 phosphates. These substances are, however, usually present 

 in sufficient quantity in the soil, and therefore the question 

 is generally one of phosphates and of nitrates. 





