HINTS ON SOILS AND FERTILIZERS 67 
at work, either on top of the soil, or in the 
soil. This process takes place more rapidly in 
the soil, however, than on top of the soil, due 
to the fact, that these decomposing organisms 
are far more numerous within the soil than 
elsewhere. When we add any kind of material 
to the soil, and then turn this material under, 
so that it is thoroughly incorporated in the soil, 
these bacteria at once begin to break up the 
material into some of its original elements. If 
such a decaying process were not possible, we 
could easily see that the world would be littered 
up with an immense amount of trash from past 
products. 
When the farmer turns under, by means of 
the plow, the various materials that we have 
discussed in these pages, these bacteria im¬ 
mediately commence to decompose this ma¬ 
terial, so that in a reasonable length of time, 
it is broken up into its several original ele¬ 
ments, and these elements are then ready to 
be taken up by some other plant, and begin 
their nourishing function anew. Thus we see 
that there is a continual rotation of these ele¬ 
ments. We can change the forms of these ele¬ 
ments in various ways, but we can never de¬ 
stroy them, they are ever present in some 
form to be used again and again. 
The story of the bacteria, which live in small 
nodules on the roots of leguminous plants, is 
intensely interesting to anyone, and particularly 
so to the farmer who is in the habit of raising 
any great quantity of such crops. Anyone can 
see these nodules, or small bunches, on the 
roots of such leguminous plants by pulling up 
