165 



Having thus described the several inorganic elements found to be 

 essential in a fertile soil, and alluded briefly to their office, both in the 

 soil and the plant ; and having given a Table of the relative proportions 

 of the elements necessary, we are prepared to examine the different 

 crops of grain, grasses and roots, which are commonly cultivated among 

 us, with respect to the composition of their inorganic elements and their 

 l-elative proportions in different plants. This will enable us properly to 

 appreciate the existing relation of these crops to the soil ; and the amount 

 of the inorganic material^ which they severally remove from it, and con- 

 sequently the necessity there is, in order to preserve the fertility of the 

 soil, of restoring, in proper quantities, these elements, by artificial means. 



It is not to be understood by our remarks, in the earlier part of this 

 article, that every kind of plant, under any and all circumstances, will 

 have, in its composition, precisely the same amount of each different 

 material. The ash of the same plant, if ripe and in a healthy and per- 

 fect state, is nearly the same in kind and quality, whatever may be the 

 circumstances of soil and climate, Avhere it may have grown. This 

 general truth, however, is consistent with certain differences, which are 

 of great interest in their bearing upon Agriculture, both in theory and 

 in practice. 



We have already mentioned the fact that different parts of the same 

 plant differ in the amount of inorganic elements taken into their composi- 

 tion, and also that they differ in the relative proportions of these elements. 

 We may also add that the quantity and relative proportions of the differ- 

 ent inorganic substances varies, in the same plant, with the season of the 

 year, or the age of the plant, when the examination is made. This fact 

 is the basis for determininof the . time of harvestincr the several kinds of 

 grain, and the cutting of grass and green crops for fodder. No principle 

 connected with the management of a farm is of more vital importance to 

 the condition of the farmer's stock, and to the value of his grain, than 

 this. It is one, too, with which he should render himself familiar, and 

 upon which he should constantly act. We may, with propriety, speak 

 of feeding plants, as we do of feeding animals, and there is a principle in 

 both of these instances, analogous to each other, with which, if the 

 farmer is acquainted, and acts accordingly, complete success is sure to 

 attend his efforts. The law, which is abundantly established, both in 

 the plant and in the animal, that certain elements or bodies are deter- 

 mined towards specific parts, should be recognized by every agriculturist. 



