GREEN MANURING. 



CHAPTER XXX. 



VEGETABLE MANURES. THEIR ACTION Uf>ON THE 



SOIL AND THEIR VALUE AS PLANT FOOD. 



GREEN MANURING. 



Vegetable manures consist of green crops grown for the 

 purpose, plowed into the soil; of the roots and remains of 

 the crops; and of any vegetable matter which may be gath- 

 ered for the purpose of increasing the bulk of the common 

 farm manures. Green manuring is the plowing in of any 

 green crop in its fresh state and while growing upon the 

 soil. It is necessarily an economical operation as regards 

 labor, and is especially well adapted for the manuring of 

 distant fields, or of hilly land where manure could not be 

 hauled except with much labor and expense. But this 

 practice is advantageous in other respects. Air and water 

 it has been shown are most effective agents in the de- 

 composition of organic matter, and green vegetable sub- 

 stances contain much Avater in themselves and are much 

 mixed with air when loosely covered with soil ; hence they 

 decompose very rapidly and become serviceable when thus 

 mixed with, the soil. 



The sap of plants contains certain compounds of nitrogen 

 which not only very readily decompose, but have the prop- 

 erty of inducing by their own decomposition, the elements 

 of other substances, with which they come in contact in the 

 soil, to assume new forms and to undergo various changes 

 by which they enter into new combinations. The sap of 

 plants, in its own rapid decomposition, quickly propagates 

 in the woody fiber and other substances of the plants, an 

 active fermentation which results in the speedy decomposi- 

 tion of these substances of which the plants are composed. 

 Then the elements of which sap and the solid substance 

 of the plants are composed form new compounds, which are 

 useful to the growing crops, and which supply them with 

 food. This action going on, in and under the soil, is not 



