CHAPTER XI 



ORGANIC MATTER AND ITS TRANSFORMATION 



BY BACTERIA 



The great difference between a mass of finely ground rock and 

 soil is that the latter contains intimately mixed with it varying 

 quantities of organic matter. Although the quantity present in the 

 soil is usually small, yet it is vitally important. The temperature, 

 the structure, and the water-holding power are dependent upon the 

 quantity and kind present. It determines the kind and speed of 

 chemical reaction which occur. Last, but not least, it is the life 

 of the soil, for iit is in, and on it that bacteria work. They pull 

 it to pieces, not in a haphazard but in sl systematic manner. All 

 the resulting blocks are sorted and arranged so they may be used 

 ag-ain in the wonderful scheme of creation. 



Quantity of Organic Matter.— A sandy soil may be devoid of 

 organic matter, while a peaty soil may contain 90 per cent or 

 over. Hence, the variation is wide, depending upon the plants 

 and plant residues which come to the soil. Soils of warm, humid 

 regions contain more than do soils of arid regions; pastures and 

 grass lands contain more than cultivated. The methods of har- 

 vesting grains in the arid regions tend to leave large quantities of 

 straw on the soil. And how important it is. But how does the 

 farmer treat it? Is it plowed under to modify the physical, 

 chemical, and biological properties of the soil? Or is it burned? 

 When one sees the latter being done he feels like saying, as did 

 one writer, "Watch a crowd of boys who are out for fun, and see 

 if this fun is shared by the things they find — frogs or turtle, 

 butterfly or bird, moth or beetle, flower or bee. ... A boy 

 and a dog are never so happy as when they start out together to 

 kill something. The boy whistles and sings^ the dog barks and 

 prances. Neither one of them would be so overjoyed if he were 



