176 MINERALIZATION AND SOLVENT BACTERIA 



The actual ratio found showed that about one pound of phos- 

 phorus and about two pounds of calcium are made soluble for each 

 pound of nitrogen oxidized, aside from the action of the acid radicals 

 associated with the ammonia. The carbonic acid would play an 

 important part also in this reaction: 



4H 2 CO 3 + Ca 3 (PO 4 ) 2 = 2Ca(HCO 3 ) 2 + CaH 4 (PO 4 ) 2 



They found that neither ammonia-producing bacteria nor nitrate 

 bacteria liberated appreciable quantities of soluble phosphorus from 

 insoluble phosphates. 



Whereas this would readily occur in soil poor in calcium carbonate, 

 in those rich in calcium carbonate there would be only small quanti- 

 ties of phosphorus liberated, according to Kelley. But where the 

 soluble phosphorus is being rapidly removed by the growing plant, 

 or even by bacteria, there is little doubt that the various soil organ- 

 isms play an important part in rendering phosphorus soluble, for 

 results obtained at the Utah Experiment Station show there to be a 

 relationship between the increased nitrification produced by various 

 salts, and the quantity of water-soluble and organic phosphorus in 

 the soil. This is illustrated by the following results which give the 

 nitric nitrogen, water-soluble and organic phosphorus in a soil after 

 various treatmejjts, the untreated soil being considered as 100 per 

 cent. 



PER CENT. NITRIC NITROGEN WATER-SOLUBLE AND ORGANIC PHOS- 

 PHORUS OCCURRING IN SOIL RECEIVING VARIOUS SALTS. 



Water- 

 Nitric soluble Organic 

 nitrogen. phosphorus. phosphorus. 

 Treatment. Per cent. Per cent. Per cent. 



None 100.0 100.0 100.0 



312 x 10-7 mol. MgSO 4 . . . 101.2 105.2 111.6 



26 x 10-7 mol. Fe 2 (SO 4 )3 . . 102.0 94.3 142.3 



625 x 10-7 mol. Ca(NO 3 ) 2 .. 102.0 114.3 97.5 



156 x 10-7 mot. KNO 3 . . . 106.4 108.1 103.3 



625 x 10-7 mol. KC1 .... 106.5 105.8 107.3 



312 x 10-7 mol. Mg(NO 3 ) 2 . . 106.5 115.5 95.1 



125 x 10-6 mol. MnCOs . . . 108.4 107.5 162.6 



156 x 10-7 mol. MnCl 2 . . . 112.9 100.2 98.4 



78x 10-7 mol. MnSO 4 . . - 113.2 94.3 107.9 



13 x 10-4 mol. FeCOg . . . 117.4 105.6 94.8 



25 x 10-6 mol. MgCl 2 . . . 123.2 109.7 96.5 



625 x 10-7 mol. Mn(NO 3 ) 2 . . 125.4 84.8 87.9 



84 x 10- fi mol. FeCls . . . 128.3 105.6 94.8 



25 x 10-6 mol. MgCOs - - - 140.7 98.2 72.2 



- 1 x 10-8 mol. NaCl ... 142.0 109.3 138.7 



1 x 10-8 mol. CaCl 2 . - - 167.2 114.9 88.2 



2 x 10-s mol. CaSO 4 . . . 196.7 73.5 103.3 



Moreover, it is evident that Azotobacter in their metabolism trans- 

 form soluble inorganic soil constituents either into soluble or into 

 insoluble organic forms. This is especially true of phosphorus which 



