Tiaiisforniation of Phosphorus 235 



Thi" h\ tlioiicn siilficU' loniiccl in the rt'ductioii ol sullalcs iiia\' attain 

 he oxidized to sulfate upon coming in contact with an oxygen source 

 and in the presence of the specific sulfur-o\i(h/.ing hacteria. 



Transformation of Phosphorus 



Phosplu)rus is coiitinuonsK' added to the soil in organic residues 

 and in fertilizers. It is also found in untreated soil in a niunher of 



'J'aui-k .)4. PiKisi'iioiii s AND TorAfssnM (Ontknt of Somk Tvi'ical Soil Hacteuia 



Asli Total IM)5 Total K'.jO 



per cent per cciil per cent 



Az.cliroororcuin 8. '2-8. (5 4.<J3,5.'-2 '2.41 -'2. Co 



li. mycoidcs 7.'> 4.07 2.27 



Ps.fI)iorr.\Tciisli(jiirf(iriciis (i.48 5. Si 0.8,S 



different forms. Briefly these forms of phosphorus may be classified 

 as follows: 



1. Organic compounds present in plant and animal residues added 

 to the soil. They are also abundant in the microbial cell substance 

 ^^'hich is synthesized in the soil. Organic compounds of phosphorus 

 also form a constituent part of the humus complexes of the soil. 



2. Rock phosphate and other insoluble phosphates are usually 

 present in the native rocks from which the soil is derived. They 

 are also frequently added to the soil in the form of various fertilizers 

 as well as in the bones of dead animals (Table 55). 



Table 55. Effect ok Xithificatiox ox the Souijility ok Thicalcilm 

 Phosphate in Soil (from Kelley) 



