NITROGEN, NITRIFICATION, NITROGENOUS MANURES 1 



assumed a deeper green, new growth was begun, and 

 finally four seeds were produced. 

 During the time of seed formation 

 more nitrogen was added, but with no 

 beneficial result. All of the essential 

 elements for plant growth were liber- 

 ally provided, except nitrogen, which 

 was very sparingly supplied, until near 

 the period of seed formation. 



When plants have reached a certain 

 period in their development, and have 

 been starved for want of nitrogen, the 

 later application of this element does 

 not produce normal growth, as the en- 

 ergy of the plant appears to have been 

 used up in searching for food. Nitro- 

 gen, as well as potash, lime, and phos- 

 phoric acid, are all necessary while 

 plants are in the first stages of growth. 



In the case of wheat, nitrogen is as- 

 similated more rapidly than are any 

 of the mineral elements. Before the 

 plant heads out, over 85 per cent of 

 the total nitrogen required has been 

 taken from the soil. 37 Corn also absorbs 

 all of its nitrogen from four to five 

 weeks before the crop matures. Flax 

 takes up 75 per cent during the first fifty days of 

 growth. 38 



FIG. 29. Oat Plant 

 grown without Ni- 

 trogen. 



