RECLAIMING LOST NITROGEN 133 



change; and so it has been from the time that plants 

 became fixed occupants of the land. 



How nitrogen is lost. There are other ways by which 

 nitrogen is lost to the soil than that previously men- 

 tioned : the loss through denitrifying bacteria. The many 

 ways by which these losses occur are : 



1. The loss due to fire and chemical change. 



2. The transfer of nitrogen to the ocean. 



3. The loss of nitrogen salts in drainage waters. 



There is no plan that may be suggested that will com- 

 pletely remove these losses. Some cannot be lessened, 

 even. Fire is essential for heat and mechanical power. 

 When wood, straw and other combustible materials are 

 consumed, the compounds composing them are split up : 

 mineral materials sink back to the soil (available for 

 plant uses, if not lost), carbon and nitrogen, freed from 

 their prison cells, fly off into the air and are reclaimed 

 to the atmosphere ; and water, loosed from the cords that 

 bind it, vaporizes and joins its kind in the clouds above. 



When these agencies are considered their constant 

 activity, their labors in every season and in every place 

 you can realize, readily, the enormous quantities of ni- 

 trogen that are dissipated annually and lost, conse- 

 quently, to the stores in the earth. 



The ocean gets its share, also. And a tremendous con- 

 tribution it is. Consider the enormous quantities of hu- 

 man foods that, each year, go to cities and towns and 

 other places of consumption throughout the world. The 

 greater part of these immense stores reach the ocean 

 sooner or later by means of sewers and streams and 

 rivers positively lost to plants and to man. 



Then the loss of nitrogen in drainage waters is not 

 inconsiderable, either. This is more constant and larger 

 than you may think on first consideration. Every rain 



