PRACTICE V 



DETERMINATION OF NITROGEN IN FARM PRODUCE 



Each group of students will work upon one of the following 

 materials : l 



1. Wheat. 5. Oats. 



2. Corn. 6. Oat straw. 



3. Corn stover. 7. Red-clover hay. 



4. Corncobs. 8. Alfalfa. 



Weigh out exactly 2 g. of the material numbered with your group 

 number and determine the nitrogen in it according to the method 

 given in Practice IV. 



Titrations cc. NH 3 



Titrations cc. NH 3 



Av cc. NH 3 



Per cent N 



Pounds per ton 



Calculate the results obtained, and with these record the results 

 obtained by three members of each group as indicated upon the 

 following page, valuing nitrogen at 15 cents per pound. How many 

 tons of red clover must be plowed under in order to supply in this 

 way the nitrogen for a 100-bushel crop of corn and a 100-bushel 

 crop of oats in a corn, oats, and clover rotation ? 



Compute the pounds of nitrogen required to produce the crops 

 given in the table below. Compute the weight of sodium nitrate 

 (95 per cent pure) which would supply the nitrogen found in these 

 crops, and the cost of the same. 



1 These or other stock materials of large importance in agriculture should be 

 furnished by the laboratory in finely pulverized, air-dry condition. The student is 

 encouraged to determine nitrogen in some other produce which may be of special 

 local interest in his home communitv- 



10 



