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ILLINOIS STATE ACADEMY OF SCIENCE 



Fig. 2. Percent phosphorus recovery from phosphatic fertilizer treated 

 brown silt loam. 4 mgs. of phosphorus were used for 25 gms. of soil. 

 Nos. 1, 2, 3, etc. at the bottom of the figure refer to numbers oppo- 

 site the fertilizer materials in table 3. 



■1 



-1 



Fig. 3. Percent of phosphorus recovery from 25 gms. of brown silt 

 loam and brown gray silt loam treated with 4 mgs. of phosphorus of 

 either Tennessee rock phosphate, R, P., or double .acid phosphate, 

 D. A. P. Five consecutive extractions were made with HN0 3 N/5. 

 First extraction data represented at the base line. Subsequent ex- 

 tractions are placed above, in order named. 



