The Three Essential 

 Elements of Plant Food 



What 



NH, 



Means 



Sources 



of 



Nitrogen 



Nitrogen, the First Element 



Of the three essential elements of crops (nitrogen, phos- 

 phorus and potash) which the farmer must supply, we place 

 nitrogen first in the group, not because it is the most im- 

 portant, but because it is relatively the least abundant in 

 an available form and therefore the most costly. As we 

 know, there is an inexhaustible supply of nitrogen over every 

 acre of soil, and why nature arranged that it should not be 

 available to the great family of plants is an interesting question 

 for scientific speculation and investigation. 



Nitrogen (N being its symbol in chemistry) is known in the 

 trade as ammonia, the terms being used interchangeably. As a 

 matter of fact, ammonia is a combination of nitrogen and hydro- 

 gen (NH3), that is, one part nitrogen to three parts hydrogen, 

 100 lbs. of ammonia containing 82 lbs. of nitrogen. The form 

 of ammonia that is best known is hartshorn, which is water 

 and ammonia combined. 



Nitrogen is a gas without color, odor or taste. As plants can- 

 not absorb it directly from the atmosphere, it must be added in 

 the manure or fertilizer applied. Except in the air it always exists 

 in combination with some other element, and yet it is always 

 hastening back to the state of single-blessedness, to the pure 

 nitrogen of the atmosphere through the process of nitrification 

 or decay. 



The sources of nitrogen are the humus of the soil, animal ma- 

 nures, and what are known as organic ammoniates, such as packing- 

 house refuse, tankage, dried blood, and fish waste or scrap, 

 also the seeds of plants such as cotton-seed or linseed. Then 

 there are chemical sources, chiefly nitrate of soda (a natural 

 deposit found in South America), and sulphate of ammonia, 

 a chemical by-product made by gas and coke works. Some soft 



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