36 HARNESSING THE EARTHWORM 



tation, manures, dead animal residues constitute the cheap and 

 ever-renewed source of earthworm food for profitable soil- 

 building. 



The microscopic life of the earth and soil is vastly greater 

 than the animal life which we see on and above the earth as 

 beasts, birds and man. In fertile farm land, where it has been 

 handled by organic methods, we may find as high as 7,000 pounds 

 of bacteria per acre in the superficial layer of topsoil, eternally 

 gorging on the dead and living vegetable material, on each other 

 and on dead animal residues all producing earthworm food, all 

 in turn becoming earthworm food. 



The unseen vegetable life of the soil algae, fungi, moulds 

 form an additional great tonnage of material which eventually 

 becomes earthworm food. The living network of fine roots, so 

 important in holding the soil in place, constitutes about one-tenth 

 by weight of the total organic matter in the upper six inches of 

 soil it is all destined to become earthworm food. In the good 

 black soils, the organic matter earthworm food is represented 

 by jrom 140 to as high as 600 tons of humus per acre. The earth- 

 worm will not go hungry. 



In the accumulation of the great tonnage of humus as found 

 in the good black soils, nature has taken her time. In the slow 

 processes of nature, it is estimated that from 500 to 1000 years 

 are required to lay down one inch of topsoil seldom so short a 

 time as 500 years. The source of humus, as has been pointed out, 

 is mainly vegetation. Into the structure of the plant, in the exact 

 proportions necessary to reproduce vegetation, nature has com- 

 bined the elements of nutrition for all life. These elements are 

 derived both from the earth and from the air. Taking 1000 

 pounds of dry vegetation as a unit of measurment, on the aver- 

 age, we find upon analysis that it contains 50 pounds of chemicals 

 derived from the earth and 950 pounds of chemicals derived from 

 the air. 



