HUMUS 



215 



3. 

 4. 

 .5. 

 6, 



7. 



S. 



1601 

 1605 

 1605 

 1605 

 1605 



107-134. 



25. 



116-120. 



123-124. 



126. 



drocarbons into a soluble form, potassium chloride is best for 

 fertilizing purposes, and this is especially true during the 

 period of fruition. 



References : 



1. 1601 : 80-81. Potassium in the Soil. 



2. 1601 : 101-106. The Store of Plant Food. 



Nitrogen of the Soil. 

 Potash. 



Nitrogen and its Fixation. 

 Phosphorus. 



Lime as an Amendment. 

 Farmers' Bulletin No. 77 : 7-9. Chemical and Physical 



Effects of Lime. 

 Sources of Plant Food. 

 Root Tubercles. 

 Food from the Soil. 

 Enriching the Soil. 

 Applied Plant Food. 

 Potassium in Plants. 

 Sources of Plant-food Elements ; the Air 



and the Soil. 



Plant Food in Soil Water. 

 The Elements that Plants Use. 

 Available and Nonavailable Plant Food. 



153. HUMUS 



Humus is composed of decayed vegetable and animal matter 

 which, in the natural humus, has accumulated through untold 

 thousands of years. It is what gives the soil the dark color, 

 and is absolutely necessary for plant life. As has been noted, 

 it increases the water-holding capacity, loosens heavy soils, 

 and serves as food for bacteria, which play such an important 

 part in agriculture. 



Living upon the humus to a great extent, the bacteria cause 

 decay, and produce nitric acid from the nitrogen contained in 



