ID/ 



Variations in composition are noticeable. The hu- 

 mus produced from each material, as green clover, oat 

 straw, or sawdust, is different from that produced from 

 any other material. The humus from green clover is 

 very complex in nature. It contains both nitrogenous 

 and non-nitrogenous compounds, and each class has a 

 different action in humification processes; hence it fol- 

 lows that the green clover humus 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 as 

 types of non-nitrogenous and nitrogenous humus. 



116. Value of Humates as Plant Food. Various 

 opinions have been held regarding the actual value, as 

 plant food, of this product from partially decayed an- 

 imal and vegetable matter. Humus was formerly re- 

 garded as composed only of carbon, hydrogen, and 

 oxygen, and inasmuch as plants obtain these elements 

 from water and from the carboi) dioxide of the air, no 

 value was assigned to it. Later investigators added 



