Soil Conditions Affecting Nitrification 173 



ever, that, notwithstanding the lateness of the season, 

 the ammonia was rapidly converted into nitrate as shown 

 by the increased content of the latter in the drainage- 

 water from those plots. In fact, the appUcation of the 

 ammonia salts was practically equivalert to the appli- 

 cation of nitrate, and, in order to 'guard against the 

 loss of nitrogen, the fall applications of ammonia salts 

 were discontinued. 



Loss of nitrates in the soil. — The soil-nitrates all 

 dissolve in water, diffuse themselves readily in the soil- 

 moisture, and, when not taken up by the crops, are 

 liable to be washed into the drains. This property of 

 nitrates accounts for their presence in comparatively 

 slight amounts in the soil. In certain rainless regions of 

 the earth there are large accumulations of nitrate. 

 This is particularly true of the extensive deposits of 

 nitrate of soda in some provinces in Chile, South America. 

 This salt, known also as Chile saltpeter, occurs in crystal 

 form throughout a considerable thickness of solidified 

 earth, and is secured from the latter by the crushing 

 and leaching of the earthy material, and subsequent 

 crystallization of the nitrate from these leachings. 



Sources of the nitrate deposits. — Various theories 

 have been proposed to account for these deposits. 

 One of these theories, accepted by many, assumes that, 

 in the gradual rising of the coast of western South Amer- 

 ica, a portion of the sea was cut off, forming a great 

 inland bay whose waters could be replenished by the 

 ocean only at high tides. Immense quantities of sea- 

 weed developed in this shallow bay, and, on their decay, 

 were changed by the nitrifying bacteria into nitrate. 



