12 MANUFACTURE OF FERTILIZING MATERIALS 



lime, care should be taken not to use too large 

 quantities at a time, and, ordinarily, it is best 

 to use it in connection with a liberal application 

 of nutritive fertilizer. Lime can be used to ad- 

 vantage on freshly drained swamp-lands and also 

 on lands newly cleared. 



The explanation of the chemical action of lime 

 on soils may be in order here. Before nitrogen in 

 ammonium sulphate or organic substances can be 

 taken up by plant life, it must be converted into 

 nitrates. The nitrogen in organic substances is 

 chiefly in an albuminoid form. The first de- 

 composition which such substances undergo re- 

 sults in the production of ammonia. The oxida- 

 tion necessary for the conversion of ammonia 

 into nitric acid is dependent upon the presence 

 of a so-called "nitrifying" organism, which is 

 a bacillus to which the name of "nitromonas" 

 has been assigned. The organism requires the 

 usual mineral constituents, e.g., phosphates, for 

 its growth, and free access of air, on which account 

 it is not active in the ground at a greater depth 

 than six feet. The formation of nitrates appears 

 to be always due to the action of the same or- 

 ganism; nitrites, on the other hand, are pro- 

 duced by several different species, which vary 

 with the locality. In order that all the ammonia 

 may be converted into nitric acid, a fixed base 

 must be present, like lime, otherwise ammonia 

 nitrate is the final product. The temperatures 

 between which the organisms can act are 3 and 



