SOILS 23 
and who draw for their food the nitrogen from the air, 
and drawing more than they need, store the surplus 
in the soil where it becomes available for plant food. 
There are thousands of nitrogen-gathering plants, some 
of them being the trees of the forests. 
Go into the virgin forest such as once covered the 
middle west — and there are some such forests existing 
to-day, but they are not large — and you will see between 
the trees, the ground covered with decayed and decaying 
tree trunks and limbs and a heavy coating of leaves. A 
large number of the trees, and much of the undergrowth 
of these forests, are of the legume family, or the nitrogen 
gatherers of the soil. 
This decaying of trees and leaves, and nitrogen gath- 
ering, has been going on for hundreds of years, thus 
storing up a vast storehouse of precious elements of rich 
soil. Is it any wonder then that lands when first cleared 
of the virgin forest were so rich? 
Continued cultivation of cleared lands without the ad- 
dition of anything to reproduce these original elements 
has exhausted them from our soil, and until we can get 
them back into the soil again, our lands, lacking in these 
elements, will become more worthless as the years go by. 
When we consider that it took centuries to put large 
quantities of nitrogen, organic matter and humus into 
our soils, it seems an impossible task to get back into 
these soils again within a short time the quantities of 
nitrogen, organic matter and humus that took so long to 
put there in the first instance. | 
Barnyard manure will put these elements back into the 
soil quicker than any other known agency, but this rem- 
