NITROGEN, NITRIFICATION, NITROGENOUS MANURES I2Q 



POUNDS OF 

 NITROGEN PER 

 ACRE REMOVED 



IN CROP 38 



Wheat, 20 bushels 25 



Straw, 2000 pounds 10 



Total 35 



Barley, 40 bushels 28 



Straw, 3000 pounds 12 



Total 40 



Oats, 50 bushels .* 35 



Straw, 3000 pounds 15 



Total . . . ' 50 



Flax, 15 bushels 39 



Straw, 1800 pounds 15 



Total 54 



Potatoes, 150 bushels 40 



Corn, 65 bushels ..." 40 



Stalks, 3000 pounds 35 



Total 75 



140. Nitrates and Nitrites. Nitrogen in the form of 

 nitrates and nitrites varies from mere traces to 150 

 pounds per acre. Soils with large amounts of nitroge- 

 nous humus and lime may contain for short periods as 

 high as 300 pounds of nitrates and 15 pounds of nitrites, 

 calculated as sodium salts. Some soils contain more 

 nitrates than are utilized by crops as food, and plants 

 may assimilate more than they can convert into protein. 



K 



