96 SOIL BACTERIOLOGY 



1. After dissolving the agar by steaming for one hour or 

 more, add the dibasic potassium phosphate and magnesium 

 sulphate. 



2. The asparagin and dextrose should be added just 

 before sterilizing. 



3. Adjust the reaction to (+1.0). 



Medium 9 

 Urea-ammonium Nitrate Agar for Soil Bacteria 



Agar 15.0 gm. 



Dibasic potassium phosphate (K 2 HPO 4 ) 0.5 gm. 



Magnesium sulphate (MgSO 4 + 7H 2 O) 0.2 gm. 



Dextrose (C 6 Hi 2 O 6 ) 10.0 gm. 



Urea (CO(NH 2 ) 2 ) 0.05 gm. 



Ammonium nitrate (NHUNOs) o.i gm. 



Ferric sulphate (Fe 2 (SO 4 ) 3 ) trace 



Distilled water 1000.0 c.c. 



The urea, ammonium nitrate, and dextrose should not be 

 added until the medium is ready for sterilization. The 

 reaction should be about (+0.25). 



Cook, R. C., Soil Science, vol. i, No. 2, pp. 153-161, 1916. 



Medium 10 

 Sodium Asparaginate Agar for Soil Bacteria 



Agar 1 2.0 gm. 



Ammonium biphosphate (NH 4 )H 2 PO 4 1.5 gm. 



Magnesium sulphate (MgSO 4 + yH 2 O) 0.2 gm. 



Sodium asparaginate (NaC 4 H 6 NO 4 -f- H 2 O) i.o gm. 



Dextrose (CeH^Oe) i.o gm. 



Calcium chlorid (CaCl 2 ) o.i gm. 



Potassium chlorid (KC1) o.i gm. 



Ferric chlorid (FeCla + 6H 2 O) trace 



Distilled water 1000.0 c.c. 



The sodium asparaginate and dextrose should not be added 

 until the medium is ready for sterilization. The reaction 



