10 Fertilizers 



same soils contain practically no nitrogen. This differ- 

 ence in the loss of nitrogen under the two conditions may 

 not seem a great matter at the first glance, but a careful 

 study of the bearing of this loss in its relation to crop 

 production shows that it is really a serious matter. In 

 the first place, the amount of possible loss annually is 

 practically equivalent in nitrogen to the amount con- 

 tained in two tons of timothy hay, or in one ton of either 

 wheat, rye, oats, corn or buckwheat, quantities nearly 

 double the average yield to an acre of these crops through- 

 out our whole country ; and in the second place, that the 

 nitrogen which is carried away by the drainage water is 

 in the very best form for feeding the plant, or it would 

 not have been lost, and thus its loss leaves the soil not 

 only poorer in this constituent element, but poorer in 

 the sense that the remainder of it in the soil is in a less 

 useful form. Furthermore, if this nitrogen is to be re- 

 turned to the soil in the same form, which is the cheapest, 

 it would cost at present prices $6.85. 



Escape of nitrogen into the atmosphere. 



Another source of natural loss of nitrogen is its escape 

 from the soil as gas into the atmosphere. This is due to 

 the oxidation of the vegetable matter, or to "denitrifica- 

 tion," which takes place very rapidly when soils rich in 

 vegetable matter are improperly managed. The possi- 

 bilities of loss in this direction are strongly shown by in- 

 vestigations carried out at the Minnesota Experiment 

 Station on "the loss of nitrogen by continuous wheat 

 raising." The results of these studies show that the total 

 natural loss of nitrogen annually was far greater than the 

 loss due to the cropping. In other words, by the system 

 of continuous cropping, which is universally observed in 



