SOIL COVERING 71 
a soil works hardest when it is growing weeds, grasses 
and trees. 
An observer of Nature sees a great lesson in the 
neglected fence row. It demonstrates Nature’s way of 
soil covering, soil building and soil restoration. 
When the land occupied by the fence row was no 
longer cultivated and was neglected and for the time 
abandoned by the farmer, Nature took it in hand for 
rebuilding and first prepared it for the growing of 
grass by the growing of different kinds of weeds which 
filled and covered the soil with the decayed roots and 
tops. 
The grass came, whose roots and tops furnished addi- 
tional organic matter and provided a soil covering that 
gathered and retained the nitrates. 
Then the little trees came which stirred the soil with 
their rapidly growing roots. Some of the weeds, 
grasses and trees were of the legume family and so 
stored the precious nitrogen into the soil. 
The roots of the weeds and trees went down deep 
into the soil and brought up potash and other minerals 
which were stored into the leaves, branches and trunks, 
to be transferred to the soil when they fell down on the 
soil and decayed. In this illustration we have all the 
lessons of organic matter, soil stirring, soil covering 
and their importance in restoring worn soil. 
The secret of soil covering in promoting soil fertility 
lies in the fact that covered soil prevents ammonia 
wastes from the soil by evaporation, and the loss of 
nitrogen. 
To preserve soil fertility, it must be kept covered as 
