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PRACTICE 24. 

 DETERMINATION OF PHOSPHORUS IN FARM PRODUCE. 



Each group of students will work upon one of the following products : 



1. Wheat. 5. Oats. 



2. Corn. 6. Oat Straw. 



3. Corn Stover. 7. Red Clover Hay. 



4. Corn Cobs. 8. Alfalfa Hay. 



Weigh out 2 gm. of the material in a 25 cc. crucible, moisten with a 

 ?o% solution of ammonium nitrate, and ignite in a muffle furnace at a 

 low red heat for two hours. Transfer to a 250 cc. beaker, dissolve in about 

 15 cc. of hydrochloric acid, dilute to about 40 cc., filter and wash. Evap- 

 orate the filtrate and washings to about 25 cc. and determine phosphorus 

 according to directions given in Practice 21, using only 10 cc. of the am- 

 monium molybdate solution. 



cc. HNO 3 cc. KOH to mg. P #P 



used dissolve ppt. 



Ave .... 



Calculate the results obtained and record with these the results ob- 

 tained by three members of each group as indicated on the following page. 

 Value phosphorus at 12 cents per pound. 



How many pounds of steamed bone meal will it require to replace the 

 phosphorus removed from the soil in a loo-bushel crop of corn, a 75- 

 bushel crop of oats, and a 3-ton crop of clover hay (see Practice 9) ? 



