2l6 



PRINCIPLES OF AGRICULTURAL CHEMISTRY 



soil, and the conditions surrounding it. Nitrification and am- 

 monification, if too slow, will not provide the growing plant with 

 sufficient food ; if nitrification is too rapid, the excess of nitrates 

 may be washed out and lost, thereby diminishing the productive 

 power of the soil. 



The following is an illustration of the effect of moisture : 

 EFFECT OF WATER ON PRODUCTION OF ACTIVE NITROGEN. 1 



The most favorable amount of water for the production of 

 nitrates in the first soil was 3/9 of its capacity. Little or no 

 nitrification took place when the soil was very wet, though a con- 

 siderable amount of ammonia was produced. Plants which grow 

 in swamps or saturated soils must secure their nitrogen from am- 

 monia or organic bodies. 



Nature of the Soil. By the nature of the soil is meant the 

 complex of physical and chemical properties which make up the 

 soil properties. Which of these properties are of predominating 

 influence in the production of active nitrogen, remains to be ascer- 

 tained. 



The nature of the soil has a decided effect upon the course of 

 nitrification within it. Different soils when placed under similar 

 physical conditions, and provided with an equal number of 

 nitrifying organisms and the same food for them, produce differ- 

 ent quantities of nitrates. The quantity of ammonia and nitrates 

 together which is formed is not, however, so different. The 

 following table shows the differences in some soils in the produc- 

 tion of nitrates and ammonia: 

 1 Fraps, Texas Station Bulletin 106. 



