100 Dilute Acids and Phosphorus Compounds in the Soil 



Table VII {continued). 



Bramford subsoil (extracted)*. 



Time = I hour. Nf 10 HNO^. Temperature 23° C. 



100 grms. of soil to 1000 c.c. of solution. 



P2O5 by diffusion = 90-9 mgms. per 100 gms. of soil. 

 P2O5 removed = 83-0 ,, ,, ',, „ 



.•. P2O5 left in soil = 7-9 „ ,, ,, ,, 



P2O5 added (mgms. per 

 lOOOc.c.) ..." 



P2O5 found in solution (C) 

 (mgms. per lOOOc.c.) ... 



P2O5 left in soil (y) (mgms. 

 per 100 gms.) 



32-8 

 30-6 

 101 



Equation obtained : 2/ = 2-7 C2'6 . 



* The Bramford soil contained so much P2O5 that it hardly showed the ordinary 

 adsorption phenomena: instead therefore of working with the surface suil we used the 

 subsoil, and treated it with N/5 HNO3 to remove jjart of the P2O5. 



Time = 1 hour. Hoos 2 C. iV/5 HNO^ 



P^Os added (mgms. per 



"lOOOc.c.) 



PjOj found in sulution (C) 



(mgms. |;cr lOOOc.c.) ... 



P2O6 left in soil (y) (mgms. 



per 100 gms.) 





 36-2 

 37-6 



190 

 550 

 37-9 



28-5 

 63-7 

 395 



380 

 72-6 

 40-8 



Equation obtained : 2/ = 187 C57 



Time = 24 hours. 



N/5 HNOs. 



PgOs added (mgms. per 

 lOOOc.c.) 



P2O5 found in solution (C) 

 (mgms. ])cr lOOOc.c.) ... 



P2O5 left in soil {y) (mgm.s. 

 per 100 gms.) 





 39-4 

 311 



9-5 

 48- 1 

 32-7 



19-0 

 571 

 33-7 



28-5 

 66-4 

 361 



380 

 73-8 

 38-4 



Equation obtained : y = 10-4 CS'i , 



