CHAPTER IX 

 THE CHEMISTRY OF MANURES 



How a plant feeds and grows — The word •' manure " or 

 •• manoeuvre " — The earliest form of " manuring " — 

 Organic and inorganic manures — Manures for various 

 crops — Green manuring and fallowing 



THIS is to be a short chapter on manures, again 

 from the point of view of the " why and where- 

 fore " of the subject, and for this purpose one is bound 

 first to consider the problem of plant life and growth. 

 In fact the question of manuring is only understand- 

 able by first examining the internal mechanism of a 

 plant, so that we may see what actually goes on before 

 that perennial miracle, growth, can take place. 



As an example let us take the common case of the 

 Haricot Bean and try to grasp the process of its deve- 

 lopment from start to finish. I should like the reader 

 to imagine that the figure shown in the accompanying 

 drawing represents a young bean Vv^hich has just got 

 its first pair of green leaves, and we are further to 

 suppose that we have taken a sharp raeor and sliced 

 the plant straight down the middle and are looking at 

 its interior cell structure. It is true that each cell 

 has been drawn about one hundred times its natural 

 size, but that is a necessary convention, the reason for 

 which is obvious. (See Plate 41.) 



To begin with, then, the process of growth is the 

 process of the formation, renewal and decay of these 



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