264 BOARD OF AGRICULTURE. 



without the substances of which this mineral portion of plants 

 is composed. They are numerous, as known in common terms. 

 But they are mainly of two classes — alkalies and acids. These 

 • are of opposite properties. A few only of the prominent min- 

 erals necessary to vegetation under these two classes will be 

 noticed. 



Potash and lime are among the most important alkaline 

 substances. 



The principal mineral acids are found in phosphate of lime, 

 wliich is also contained largely in bones, gypsum or plaster and 

 in silicate or sand. 



The farmer who has given the proper degree of attention to 

 the draining and aeration of his land, that has been indicated, 

 may have great confidence that these mineral substances are in 

 large supply, and will become gradually available to his crops. 

 The present difficulty is that they are not immediately available, 

 from the fact that they are insoluble without the action of air, 

 heat and water and the presence of other substances to bring 

 them into a proper physical combination with other plant-food, 

 so as to be easily assimilated by the roots of plants. 



The probability is — indeed, we are assured that New England 

 soil has generally all the mineral elements of fertility that are 

 contained in even the Western prairies, the only or principal 

 difference being in the fineness of the particles. 



The slow processes of nature by which the mineral substances 

 of the soil are comminuted may be profitably hastened by a small 

 outlay from the income of the farm, in those substances which 

 will act immediately and mainly upon the mineral substances 

 of the soil to decompose them. 



Potash is probably the most valuable mineral alkaline sub- 

 stance that can be named. It acts upon the mineral substances 

 of the soil to decompose them. This may be returned to the 

 soil in wood-ashes. They contain also nearly all mineral sub- 

 stances necessary to vegetation. The farmer may safely invest 

 in them as his means and experience will dictate. 



Chloride of sodium or common salt should be named in this 

 connection. It may be used safely in manures in quantities 

 large enough to destroy the seeds of weeds, and will act to 

 decompose vegetable and mineral matter. 



