NORTH-CAROLINA GEOLOGICAL SURVEY. 59 



In this variety of soil from the swampy grounds there is 

 still a deficiency of the alkalies and alkaline earths ; this, 

 however, may be cultivated with medium results, if marl is 

 at hand from which to supply the deficient matter. 



CHAPTER Y. 



FERTILIZERS. 



What constitutes a Fertilizer. Sources of Fertilizers. Those from the 

 Vegetable kingdom are the Ash. Ash of difFernt Vegetables Ash of 

 Plants resembles in composition the Inorganic Matter of Soils. Quantity 

 of Fertilizing Matter removed from the Soil by different Plants. Me- 

 thods to be adopted by which a Waste of Fertilizing Matter may be Pre- 

 vented. Fertilizing Matter Restored by Plowing in Green Crops, 



33. Any substance in husbandry is a fertilizer which im- 

 proves the soil. They are numerous and are derived from 

 numerous sources. The air is a reservoir of substances which 

 improve the soil, and water is the medium of communication. 

 As in the laboratory substances do not act upon each other 

 unless one or both are in a fluid condition ; so fertilizers must 

 be in solution in a menstrnm, of which water, in the kingdom 

 of nature, is the universal solvent The air contains ammo- 

 nia and carbonic acid. These are the most direct fertilizers. 

 They are both transferable agents, passing from the atmos- 

 phere to the earth dissolved in rain water, and escaping up- 

 ward from the earth in the ascending vapors, when they 

 have fulfilled their mission to the grown and perfect vege- 

 table. They escape when it decays, and wait for another 

 mission to the earth or soil. The interchange is almost per- 

 petual. There are vegetables at all times undergoing decay, 

 or [eremacausis,~] a slow combustion, during which the com- 

 pound atoms are undergoing a change, and each one of which 



