PAPERS OX CHEMISTRY AND PHYSTCS 



321 



TABLE 2— Concluded. 



percent 



Phosphorus 



Hecovery 



Description of soils. > £ a =S 



g| SI 



-I si 



■ fe 



TERRACE SOILS 



34 Brown sandy loam 7852 65.7 



85 Brown sandy loam, vari- 

 able 7853 46.5 



3 6 Yellow sand, some 



ciayey sand 7854 34.8 



RIVER AND BOTTOM Si 



37 Brown mixed loam 7861 48.5 



38 Brown mixed loam 7862 42.5 



39 Yellowish brown loam, 



some sand 7863 54.9 



40 Black decomposed peat, 



shells I... 7870 102.0 



41 Black peat 7871 110.8 



43 Black to brown peat, 



drab clay at 30".... ~ s "- 66.8 



Algrebraic sum 



Mean deviation 



•a I 



/ED= /451 



Standard deviation = / M 5 = / .137 = 3.256 



V N V I? 



.37 



Z = ratio of mean deviation to standard deviation = = .113 



3.256 



TABLE 3. 



Recovery of phosphorus from different phosphatic fertilizers ap- 

 plied to Brown Silt Loam. In each case 4 mgs. of phosphorus was 

 applied per 25 gins, of soil. 



Alkali re- 

 quired per 

 Mgs. Phos- Percent 10 c.c. of 

 phorus Phosphorus extracted 

 extracted extracted solution 



Tennessee Rock Phosphate 2.35 58.8 11.6 



Slag A 2.12 53.0 11.4 



Slag B 2.11 52.8 11.4 



Slag C 2.16 54.0 11.4 



Slag D 2.33 58.3 11.4 



Birmingham Slag 2.23 55.8 11.5 



Blue Rock 2.28 57.0 11.6 



Florida Soft Rock 2.37 59.3 11.6 



Apatite 2.40 60.0 11.6 



Iron Phosphate 1.91 47.8 11.7 



Aluminum Phosphate 2.32 58.0 11.6 



Acid Phosphate 2.29 57.3 11.6 



Steamed Bone-meal 2.15 53.8 11.6 



Soil, alone 11.7 



Acid, alone 12.7* 



• 10 c.c. of distilled water was used to wet the soil after fertilizer was 

 added to it. In order to make the results comparable, 10 c.c. of water was 

 added to 250 c.c. of acid before titration. 



