68 THE CULTURE OF FARM CROPS. 



large supply of this indispensable plant food may be pro- 

 cured. 



It is quite possible, not to say probable, that the oxida- 

 tion of nitrogen may occur directly in these beds. A large 

 quantity of free nitrogen is necessarily left in the mass by 

 the consumption of oxygen in the decomposition of the or- 

 ganic matter. This nitrogen is dissolved to some extent by 

 the water in the heap, the water is decomposed by the 

 chemical action, and in the aggregate result of the vigorous 

 chemical actions and reactions going on there is no violent 

 assumption in the conclusion that the free nitrogen is seized 

 upon to some extent by the omnipotent oxygen and reduced 

 to nitric acid. The possibility or probability of this is all 

 on the side of the farmer who may avail himself of it as far 

 as possible, by providing the means for it and securing the 

 results of it if there are any. 



The earth is a great magnet and electrical disturbances 

 are constantly going on, through its mass and upon its sur- 

 face. Every spark of electricity, from the lightning flash, 

 to the tiny discharge from weak currents in the soil, cause 

 a union of the elements of the air and produce nitric acid. 

 It is quite possible, and even probable, that many vexed 

 questions in regard to the source of the nitrogen gathered 

 by such plants, as clover, from the soil, may in time find 

 their solution in this direction. So far we know that a crop 

 of clover gathers an enormous quantity of nitrogen from 

 some source. All we know of the subject tends to point out 

 the soil as the source of it. A fertile soil may contain from 

 two to three tons of nitrogen to the acre, and of this a crop 

 of clover will gather in its roots and stubble and leave upon 

 the soil from 150 to 180 Ibs. ; while no other crop could ex- 

 tract from it enough to supply the needs for any profitable 

 yield. The clover has procured this nitrogen in some hid- 

 den way; how we know not; but we know the fact. This 

 is sufficient for the purposes of the farmer, who may specu- 

 late upon the causes of it, while he avails himself of the re- 

 sults. It may be however that a large portion of this 

 gathered nitrogen has been brought up from great depths 



