CONTENTS. 



PAGE. 



Preface ; 3 



Reference List ; . . 5 



List of Apparatus for Individual Use 5 



List of Apparatus for General Use G 



List of Required Chemicals •• G 



Examination of Soil Infusions 7 



Quantitative Examination of Soils 8 



Isolation and Identification of Some Soil Organisms i) 



Ammonification in Peptone Solutions 10 



Ammonification in Soils 11 



Influence of Moisture on the Ammonification of Dried Blood ... 12 



Influence of Air-Drying on the Ammonifying Power of Soils ... 13 

 Influence of Lime and Magnesia on the Ammonification of Dried 



Blood and Cottonseed Meal 14 



Influence of Fineness of Division of Dried Blood on Its Ammoni- 



flcation 15 



Influence of Dextrose on the Ammonification of Dried Blood and 



Cottonseed Meal 16 



Ammonification as Affected by Differences in the Mechanical 



and Chemical Composition of Soils 17 



Ammonification of Dried Blood by Pure Cultures of Soil Or- 

 ganisms 18 



Availability of Nitrogenous Organic Matter as Indicated by Its 



Ammonification 19 



Relative Amounts of Ammonia -and Carbon Dioxid ' Formed in 



the Ammonification of Nitrogenous Materials 20 



Influence of Dextrose on the Formation of Carbon Dioxid and 



Ammonia from Dried Blood 22 



Ammonification of Urea 23 



Isolation of Urea Bacteria 24 



Nitrate Formation in Solutions 25 



Nitrification in Solutions 20 



Nitrification in Soils 27 



Rate of Oxidation of Ammonium Sulfat in Solutions and in 



Soils in the Presence and Absence of OaCOj. 29 



Influence of Soluble Organic Matter on Nitriflcation in Soils. ... 31 

 Availability of Nitrogenous Organic Matter as Indicated by Its 



Nitrification 82 



Isolation of Nitrifying Bacteria by the Magnesia-Gypsum Block 



Method 34 



