GREEN MANURING. 179 



neglected ; marl also forms a valuable adjunct to 

 the compost pile. 



Green Manuring consists in plowing under any 

 crop that has been grown for that purpose. It 

 has been recommended and practised for cen- 

 turies. Spent or worn out soils are especially 

 benefited by this operation, and no soils can be 

 so far reduced, unless they refuse to grow any 

 kind of vegetation, that they cannot be improved 

 by this means. The least thought devoted to 

 the subject will convince the reader of its su- 

 periority over paring and burning, or leaving 

 the land fallow. In the former case, the act of 

 burning dissipates all the nitrogen, the most 

 valuable part, and the ash contains the other 

 fertilizing substance in an insoluble condition, pot- 

 ash excepted, because the greater part of the car- 

 bonic acid formed, which is naturally the principal 

 agent in rendering them soluble, is dissipated ; 

 while, on the other hand, when plowed under, 

 the carbonic acid is slowly given out during the 

 process of decay, and so makes the elements 

 soluble. The gradual decay of vegetation on 

 the surface of the land produces a like result, 

 though in a less degree. 



By growing plants with long roots, such as 

 clover and some kinds of grasses, and root crops, 

 such as beets, carrots, etc., the fertilizing ele- 

 ments often contained in the subsoil are brought 



