94 SOILS AND FERTILIZERS 



Composition of Humus Produced by 29 



Cow Green Meat Wheat Oat Saw- 



manure, clover, scraps, flour. straw. dust. Sugar. 



Carbon 41.95 54.22 4S.77 51.02 54.30 49.28 57.84 



Hydrogen 6.26 3.40 4.30 3.82 2.48 3.33 3.04 



Nitrogen 6.16 8.24 10.96 5.02 2.50 0.32 0.08 



Oxygen 45.63 34.14 35.97 40.14 40.72 47.07 39.04 



Total 100.00 100.00 100.00 100.00 100.00 100.00 100.00 



Highest. Lowest. Difference. 



Carbon 57-84 Sugar 41-95 Cow manure • . • 15.89 



Hydrogen ... 6.26 Cow manure . 2.48 Oat straw 3.78 



Nitrogen 10.96 Meat scraps . • 0.08 Sugar 10.88 



Oxygen 47.07 Sawdust 34-14 Green clover... 12.93 



The differences in composition are noticeable. The 

 humus produced by each material as green clover, oat 

 straw, or sawdust is different from that produced -by 

 any other material. The humus from green clover is 

 undoubtedly very complex in nature, because it con- 

 tains both nitrogenous and non-nitrogenous com- 

 pounds, and each class has a different action in humi- 

 fication processes, hence it follows that the humus 

 from the green clover must be a complex mixture of 

 both nitrogenous and non-nitrogenous bodies. 



The nature of the humus, whether nitrogenous or 

 non-nitrogenous, is important. Humus produced from 

 sawdust and humus from meat scraps may be taken 



 



respectively as types of non-nitrogenous and nitrog-. 

 enous humus. 



101. Value of Humates as Plant Food. — Various 

 opinions have been held regarding the actual value, 



