CHAPTER XI 



MAN'S USE AND CONSERVATION OF SOILS 



Importance of the Soil. The World War has awakened 

 most people to the dignity and importance of tilling the 

 soil. For once, it has been brought home to us that we are 

 dependent upon the nation's farms for our very > existence. 

 From the soil, either directly or indirectly, come all the 

 necessaries of life, our food, our clothing, and most of the 

 building-materials and furnishings of our homes. 



Soil. Experiment 88. Into a 16-oz. bottle nearly full of water 

 put a small handful of sand, and into another bottle about the 

 same amount of pulverized clay. Shake each bottle thoroughly 

 and allow the water to settle. Which settles the more rapidly? 

 Which would settle first if washed by a stream whose current was 

 gradually checked ? 



Wherever the inclination is not too steep, we find the 

 surface of the bed rocks covered for varying depths with 

 soil. It is upon and in this that plants grow. In it lies 

 the wealth of our agricultural communities. On examining 

 this soil, it will be found that in some places it grows coarser 

 and coarser the farther down we dig. The coarser the pieces 

 become, the more they resemble the bed rock, until finally 

 they pass by imperceptible stages into it. This kind of 

 soil is called local or sedentary soil. 



In other localities the coarseness of the soil does not 

 materially change as we dig into it, but suddenly we come 



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