RECLAIMING; LOST NITROGEN. 131 



in ordinary soil. It takes place, however, very vigorously and 

 effectively in the manure heap and compost pile, and within 

 any mass of decomposing organic matter. It is also extremely 

 vigorous in sewage where the denitrification and similar proc- 

 esses are so thorough as to cause a very large dissipation of 

 the nitrogenous compounds into a gaseous form. 



3. Drainage. The rains, as they fall upon the soils, are 

 constantly dissolving the nitrates and other soluble nitric salts 

 and carrying them by natural drainage sources to the brooks 

 and rivers and hence to the ocean. This occurs in all soils 

 and is a constant source of loss. 



4. Decomposition by chemical means. There is a consid- 

 erable amount of the fixed nitrogen store lost to the use of 

 plants by purely chemical processes. Every form of nitrogen 

 explosive depends for its basis upon some of these nitrogen 

 salts which would be of use to plant life. Their explosion 

 destroys the organic compounds and dissipates the nitrogen 

 into the atmosphere. Large quantities of the earth's nitrogen 

 store are thus dissipated. 



This problem of the loss of nitrogen has seemed to be a 

 serious one to the agricultural industry. As is well known, 

 our farm lands slowly become incapable of supporting .the 

 crops demanded of them. This loss of fertility in the soil of 

 worn-out farms is due, doubtless, to a number of factors, but 

 the loss of nitrogen is certainly the most prominent one. All 

 over the agricultural world it has been found necessary to re- 

 place this lost nitrogen in the soil. For this purpose we depend 

 mostly upon commercial fertilizers, which commonly contain 

 nitrogen in the form of nitrates. Of such fertilizers there are 

 a number of large stores in the world, especially in South 

 America, and these nitrates are brought from long distances 

 and sold at high prices. Only a few large deposits of nitrates 

 appear to exist in the world, and these are being rapidly ex- 

 hausted. The high prices of nitrates are necessary and are 



