Nitrogen 17 



both commercially and physiologically. The nitrogeu 

 balance of the farm must be carefully considered both 

 by the crop producer and by the cattle feeder. 



Nitrogen compounds are especially important be- 

 cause the available supply is often dangerously near 

 the demand or even below it. The nitrogen found in the 

 air is inert for animal uses, and is ignored by a large 

 majority of plants. Much of that in the soil is also 

 unavailable. Moreover, its immediately useful com- 

 pounds on the farm are constantly subject to loss, — 

 first by processes of fermentation which the farmer 

 cannot wholly prevent, and second by soil losses which 

 are to some extent beyond control. Many of the com- 

 mercial products of the farm also carry away much 

 nitrogen. The sources of supply to balance this outgo 

 are the nitric acid and ammonia of the rainfall, the 

 free nitrogen captured by legumes and whatever comes 

 from purchased fertilizers and foods. These facts relate 

 primarily to plant production, but they also sustain an 

 essential relation to the maintenance of animal life and 

 cannot be ignored in a rational and well-directed sys- 

 tem of animal husbandry. 



Physiologically, the nitrogen compounds stand in 

 the front rank. They are necessary building material 

 for the fundamental tissues of the animal and are inti- 

 mately related to the prominent chemical changes wdiich 

 are involved in growth and in the maintenance of life. 

 It is safe to assert, too, that variations of these com- 

 pounds in the food may have an important influence 

 on the character of the body structure or ou the 

 amount of a particulur product. 



B 



