RESULTS 



OF THE INVESTIGATIONS OF 



PROFESSOR LIEBIG, SIR HUMPHRY DAVY, 



AND OTHERS, ON 



PRODUCTIVE FARMING. , 



NECESSARY RELATION BETWEKN THE COMPOSITION 

 OF A SOIL AND THE VEGETABLES IT IS FITTED TO 

 RAISE. FALLOWING AND GREEN CROPS CONSIDERED 

 AS VEGETABLE MANURE. 



Besides heat, light, moisture, and the component ele- 

 ments of tiie atmosphere, which are necessary for the 

 mere existence of all plants, certain fertihzing substances 

 are seen to exercise a peculiar influence over the devel- 

 opment either of whole plants, or of particular parts of 

 them. Such substances are either already contained 

 in soil, or may be artificially supplied in the form of ma- 

 nure. 



The rules of a rational system of agriculture should 

 enable us, therefore, to give to each plant that which it 

 requires for the attainment of the special object in view 

 — namely, an artificial increase of certain parts which 

 are employed as food for man and animals. 



The means employed for the production of fine plia- 

 ble straw for hats and bonnets is the very opposite to (he 

 raode which must be adopted, in order to produce the 



