Tllfe KEY-NOTE OF GOOD FARMING. 31 



In the crops, as grown, of course these proportions will vary 

 according to the amount of water they contain: i,ooo lbs. of 

 turnips contain about 900 lbs. of pure water, while 1,000 lbs. of 

 ripe peas contain only about 86 lbs. Therefore, 1,000 lbs. fresh 

 peas contain about 39 lbs. of nitrogen, while 1,000 lbs. fresh 

 turnips only contain about i|^ lbs. 



The reason why nitrogen, although forming a so much smaller 

 part of the substance of our crops, is more necessary to be con- 

 sidered by the farmer than the other substances that are derived 

 from the air, is because, while there is a certain amount furnished 

 by natural means, — enough to enable plants to make a tolerable 

 growth, — they are generally benefited by the addition of an in- 

 creased supply as manure. The other atmospheric elements take 

 care of themselves. The air about the leaves and the water of 

 the sap contain them abundantly, in a form that is always avail- 

 able. With nitrogen the case is different. Although it exists in 

 the atmosphere in the form most useful to vegetation, — that of 

 ammonia and nitric acid, — the plant cannot usually obtain its sup- 

 ply through the leaves, but it must find its way into the soil and 

 enter the roots with the water that goes to form the sap. 



Ammonia and nitric acid are the universal sources of the supply 

 of nitrogen to vegetation. Ammonia is a gas formed during the 

 decomposition of vegetable and animal matters. These all con- 

 tain nitrogen, and when they are destroyed, either by fire or by 

 decay, their nitrogen escapes in the form of ammonia, or as nitric 

 acid. Usually, the original product of all destruction of organic 

 matters containing nitrogen is ammonia, which gives great value 

 to all animal manure, which is one of the manurial ingredients of 

 rain water, and which is the farmer's best assistant in making his 

 land produce the largest crops that with its supply of mineral food, 

 it is capable of growing. 



Liebig, speaking of the sources or the nitrogen of plants and of 

 the supply of ammonia, says : — 



" We cannot suppose that a plant could attain maturity, even 

 " in the richest vegetable mould, without the presence of matter 

 " containing nitrogen, since we know that nitrogen exists in every 



