THE CULTURE OF FARM CROPS. 



CHAPTEK XIV. 



SOURCES OF THE NITROGEN OF PLANTS. ITS COM- 

 POUNDS AND THEIR EFFECTS UPON THE 

 GROWTH OF PLANTS. 



While the quantity of nitrogen contained in plants is 

 small as compared with that of other elements, yet its office 

 in the structure of plants, and especially of their seeds, is 

 so important that careful and patient study of the character 

 and changes of this element is well worthy of the time em- 

 ployed. It is not always the most abundant elements in 

 nature that are the most worthy of regard. The chief pur- 

 pose of many farm crops is the seed, and although this part 

 of their substance may be quite insignificant in quantity, 

 yet it is often the most precious and highly valued ; and it 

 is in the seed that the nitrogen of plants is most abundantly 

 stored. Again while the nitrogen in the more bulky crops 

 may be but 1 to 2 per cent., this element is the most impor- 

 tant for the profitable feeding of farm stock : as it contrib- 

 utes largely to the formation of the muscular tissue and 

 supplies the waste of it by muscular exertion. 



Moreover, any substance is to be valued according to the 

 difficulty of obtaining it. A diamond is so highly valued 

 as it is, because a whole year's labor of several men may be 

 spent in the vain search for one, and its enormous price in 

 commerce merely represents the labor spent in its success- 

 ful discovery. Nitrogen is the most costly substance the 

 farmer is obliged to procure for the purpose of feeding his 

 crops, and although it is the most abundant constituent of 

 the atmosphere, yet it is so inert and passive and submits 

 to combination with other elements so unwillingly, that na- 

 ture supplies only a small portion of what the soil requires 

 of it, to produce a profitable crop. It is a most serious fact 

 in regard to this point, that the greater part of the farmers 



