FERTILIZING AND FERTILIZERS 



in many of their large and small interstices, will be 

 decaying pieces of plant roots and stems and other 

 organic matter which appear very much like logs and 

 pieces of logs rotting among masses of rock and gravel. 

 All of this organic substance will be dripping with 

 water like a soaked sponge while all the stones and rocks 

 have a layer of water over their surfaces. And finally, 

 in all the spaces where there is nothing else, there is 

 air indeed nearly half the volume of the whole cubic 

 mile is air. 



A plant root coming down into this magnified 

 cubic inch of soil would be of course an enormous thing, 

 pushing its way among the rocks and stones and decay- 

 ing matter with a great, tireless, steady, resistless, 

 pressure that would move the biggest of them. Near 

 the tip of this ever extending and down-reaching growth, 

 small hollow tubes root hairs would be seen reaching 

 out and feeling this way and that, sucking the water 

 from the surfaces of the rocks and from the dripping, 

 spongy masses among them by drawing it through 

 their thin and delicate walls. 



In this water is the mineral food, dissolved off in 

 the minutest particles from the " rocks " and it is 

 somewhat staggering to note, by the way, that in 

 order to produce one pound of growth in dry matter 

 that is in branch and leaf, flower and fruit from 300 

 to 800 pounds of water must be taken in by a plant's 

 roots, drawn up through its stalks and branches, and 

 discharged or " transpired " by its leaves. Think of the 

 stupendous work being carried on by all the silent green 



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